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Oracle® Database PL/SQL Packages and Types Reference
11g Release 2 (11.2)

Part Number E16760-04
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140 DBMS_STATS

With the DBMS_STATS package you can view and modify optimizer statistics gathered for database objects.

See Also:

Oracle Database Performance Tuning Guide

This chapter contains the following topics:


Using DBMS_STATS

This section contains topics which relate to using the DBMS_STATS package.


Overview

The Oracle RDBMS allows you to collect statistics of many different kinds as an aid to improving performance. This package is concerned with optimizer statistics only. Given that Oracle sets automatic statistics collection of this kind on by default, this package is intended for only specialized cases.

The statistics of interest to be viewed or modified can reside in the dictionary or in a table created in the user's schema for this purpose. You can also collect and manage user-defined statistics for tables and domain indexes using this package.

For example, if the DELETE_COLUMN_STATS procedure is invoked on a column for which an association is defined, user-defined statistics for that column are deleted in addition to deletion of the standard statistics.

Only statistics stored in the dictionary have an impact on the cost-based optimizer. You can also use DBMS_STATS to gather statistics in parallel

See Also:

Oracle Database Performance Tuning Guide for more information about "Managing Optimizer Statistics".

Types

Types for the minimum and maximum values and histogram endpoints include:

TYPE numarray  IS VARRAY(256) OF NUMBER;
TYPE datearray IS VARRAY(256) OF DATE;
TYPE chararray IS VARRAY(256) OF VARCHAR2(4000);
TYPE rawarray  IS VARRAY(256) OF RAW(2000);
TYPE fltarray IS VARRAY(256) OF BINARY_FLOAT;
TYPE dblarray IS VARRAY(256) OF BINARY_DOUBLE;
 
TYPE StatRec IS RECORD (
  epc    NUMBER,
  minval RAW(2000),
  maxval RAW(2000),
  bkvals NUMARRAY,
  novals NUMARRAY);
 

Types for listing stale tables include:

TYPE ObjectElem IS RECORD (
  ownname     VARCHAR2(30),     -- owner
  objtype     VARCHAR2(6),      -- 'TABLE' or 'INDEX'
  objname     VARCHAR2(30),     -- table/index
  partname    VARCHAR2(30),     -- partition
  subpartname VARCHAR2(30));    -- subpartition
type ObjectTab is TABLE of ObjectElem;

Type for displaying statistics difference report:

TYPE DiffRepElem IS RECORD (
 report     CLOB,              -- stats difference report
 maxdiffpct number);           -- max stats difference (percentage)
type DiffRepTab is table of DiffRepElem; 

Constants

The DBMS_STATS package uses the constants shown in Table 140-1:

Table 140-1 DBMS_STATS Constants

Name Type Value Description

AUTO_CASCADE

BOOLEAN

NULL

Lets Oracle decide whether to collect statistics for indexes or not

AUTO_DEGREE

NUMBER

32768

Lets Oracle select the degree of parallelism based on size of the object, number of CPUs and initialization parameters. For definition of default parallel degree, see "Degree of Parallelism" in Oracle Database VLDB and Partitioning Guide.

AUTO_INVALIDATE

BOOLEAN

NULL

Lets Oracle decide when to invalidate dependent cursors

AUTO_SAMPLE_SIZE

NUMBER

0

Indicates that auto-sample size algorithms should be used



Operational Notes

The DBMS_STATS subprograms perform the following general operations:

Most of the DBMS_STATS procedures include the three parameters statown, stattab, and statid. These parameters allow you to store statistics in your own tables (outside of the dictionary), which does not affect the optimizer. Therefore, you can maintain and experiment with sets of statistics.

The stattab parameter specifies the name of a table in which to hold statistics, and it is assumed that it resides in the same schema as the object for which statistics are collected (unless the statown parameter is specified). You can create multiple tables with different stattab identifiers to hold separate sets of statistics.

Additionally, you can maintain different sets of statistics within a single stattab by using the statid parameter, which avoids cluttering the user's schema.

For the SET and GET procedures, if stattab is not provided (that is, NULL), then the operation works directly on the dictionary statistics; therefore, you do not need to create these statistics tables if they only plan to modify the dictionary directly. However, if stattab is not NULL, then the SET or GET operation works on the specified user statistics table, and not the dictionary.

You can change the default values of some of the parameters of DBMS_STATS procedures using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

Most of the procedures in this package commit the current transaction, perform the operation, and then commit again.

Most of the procedures have a parameter, force which allows you to override any lock on statistics.Whenever statistics in dictionary are modified, old versions of statistics are saved automatically for future restoring.

Gathering Optimizer Statistics

Use the following subprograms to gather certain classes of optimizer statistics, with possible performance improvements over the ANALYZE command:


GATHER_DATABASE_STATS Procedures
GATHER_DICTIONARY_STATS Procedure
GATHER_FIXED_OBJECTS_STATS Procedure
GATHER_INDEX_STATS Procedure
GATHER_SCHEMA_STATS Procedures
GATHER_SYSTEM_STATS Procedure
GATHER_TABLE_STATS Procedure

The GATHER_* procedures also collect user-defined statistics for columns and domain indexes.

The statown, stattab, and statid parameters instruct the package to back up current statistics in the specified table before gathering new statistics.

Oracle also provides the following procedure for generating statistics for derived objects when you have sufficient statistics on related objects:

GENERATE_STATS Procedure

Setting or Getting Statistics

Use the following subprograms to store and retrieve individual column-related, index-related, and table-related statistics:


PREPARE_COLUMN_VALUES Procedures
PREPARE_COLUMN_VALUES_NVARCHAR2 Procedure
PREPARE_COLUMN_VALUES_ROWID Procedure

SEED_COL_USAGE Procedure
SET_INDEX_STATS Procedures
SET_SYSTEM_STATS Procedure
SET_TABLE_STATS Procedure

GET_COLUMN_STATS Procedures
GET_INDEX_STATS Procedures
GET_SYSTEM_STATS Procedure
GET_TABLE_STATS Procedure

In the special versions of the SET_*_STATS procedures for setting user-defined statistics, the following, if provided, are stored in the dictionary or external statistics table:

The user-defined statistics and the corresponding statistics type are inserted into the USTATS$ dictionary table. You can specify user-defined statistics without specifying the statistics type name.

The special versions of the GET_*_STATS procedures return user-defined statistics and the statistics type owner and name as OUT arguments corresponding to the schema object specified. If user-defined statistics are not collected, NULL values are returned.

Deleting Statistics

The DELETE_* procedures delete both user-defined statistics and the standard statistics for the given schema object.


DELETE_COLUMN_STATS Procedure
DELETE_DATABASE_STATS Procedure
DELETE_DICTIONARY_STATS Procedure
DELETE_FIXED_OBJECTS_STATS Procedure
DELETE_INDEX_STATS Procedure
DELETE_SCHEMA_STATS Procedure
DELETE_SYSTEM_STATS Procedure
DELETE_TABLE_STATS Procedure

Transferring Statistics

Use the following procedures for creating and dropping the user statistics table.


CREATE_STAT_TABLE Procedure
DROP_STAT_TABLE Procedure

Use the following procedures to transfer statistics


EXPORT_COLUMN_STATS Procedure
EXPORT_DATABASE_STATS Procedure
EXPORT_DICTIONARY_STATS Procedure
EXPORT_FIXED_OBJECTS_STATS Procedure
EXPORT_INDEX_STATS Procedure
EXPORT_SCHEMA_STATS Procedure
EXPORT_SYSTEM_STATS Procedure
EXPORT_TABLE_STATS Procedure

IMPORT_COLUMN_STATS Procedure
IMPORT_DATABASE_STATS Procedure
IMPORT_DICTIONARY_STATS Procedure
IMPORT_FIXED_OBJECTS_STATS Procedure
IMPORT_INDEX_STATS Procedure
IMPORT_SCHEMA_STATS Procedure
IMPORT_SYSTEM_STATS Procedure
IMPORT_TABLE_STATS Procedure

Note:

Oracle does not support export or import of statistics across databases of different character sets.

Locking or Unlocking Statistics

Use the following procedures to lock and unlock statistics on objects.


LOCK_SCHEMA_STATS Procedure
LOCK_TABLE_STATS Procedure

UNLOCK_SCHEMA_STATS Procedure
UNLOCK_TABLE_STATS Procedure

The LOCK_* procedures either freeze the current set of the statistics or to keep the statistics empty (uncollected).When statistics on a table are locked, all the statistics depending on the table, including table statistics, column statistics, histograms and statistics on all dependent indexes, are considered to be locked.

Restoring and Purging Statistics History

Use the following procedures to restore statistics as of a specified timestamp. This is useful in case newly collected statistics leads to some sub-optimal execution plans and the administrator wants to revert to the previous set of statistics.


RESET_GLOBAL_PREF_DEFAULTS Procedure
RESTORE_DICTIONARY_STATS Procedure
RESTORE_FIXED_OBJECTS_STATS Procedure
RESTORE_SCHEMA_STATS Procedure
RESTORE_SYSTEM_STATS Procedure
RESTORE_TABLE_STATS Procedure

Whenever statistics in dictionary are modified, old versions of statistics are saved automatically for future restoring. The old statistics are purged automatically at regular intervals based on the statistics history retention setting and the time of recent statistics gathering performed in the system. Retention is configurable using the ALTER_STATS_HISTORY_RETENTION Procedure.

The other DBMS_STATS procedures related to restoring statistics are:

RESTORE_* operations are not supported for user defined statistics.

User-Defined Statistics

The DBMS_STATS package supports operations on user-defined statistics. When a domain index or column is associated with a statistics type (using the associate statement), operations on the index or column manipulate user-defined statistics. For example, gathering statistics for a domain index (for which an association with a statistics type exists) using the GET_INDEX_STATS Procedures invokes the user-defined statistics collection method of the associated statistics type. Similarly, delete, transfer, import, and export operations manipulate user-defined statistics.

SET_* and GET_* operations for user-defined statistics are also supported using a special version of the SET and GET interfaces for columns and indexes.

EXPORT_*, IMPORT_* and RESTORE_* operations are not supported for user defined statistics.

Pending Statistics

The package gather statistics and stores it in the dictionary by default. User's can store these statistics in the system's private area instead of the dictionary by turning the PUBLISH option to FALSE using the SET*PREFS procedures. The default value for PUBLISH is TRUE.The statistics stored in private area are not used by Cost Based Optimizer unless parameter optimizer_use_private_statistics is set to TRUE. The default value of this parameter is FALSE and this boolean parameter can be set at the session/system level. Users can verify the impact of the new statistics on query plans by using the pending statistics on a session.

Pending statistics provide a mechanism to verify the impact of the new statistics on query plans before making them available for general use. There are two scenarios to verify the query plans:

Once the performance or query plans have been verified, the pending statistics can be published (run the PUBLISH_PENDING_STATS Procedure) if the performance is acceptable or delete (run the DELETE_PENDING_STATS Procedure) if not.

Pending statistics can be published, exported, or deleted. The following procedures are provided to manage pending statistics:

Comparing Statistics

The DIFF_TABLE_STATS_* statistics can be used to compare statistics for a table from two different sources. The statistics can be from:

The functions also compare the statistics of the dependent objects (indexes, columns, partitions). They displays statistics of the object(s) from both sources if the difference between those statistics exceeds a certain threshold (%). The threshold can be specified as an argument to the function, with a default of 10%. The statistics corresponding to the first source (stattab1 or time1) will be used as basis for computing the differential percentage.

Extended Statistics

This package allows you to collect statistics for column groups and expressions (known as "statistics extensions"). The statistics collected for column groups and expressions are called "extended statistics".

Statistics on Column groups are used by optimizer for accounting correlation between columns. For example, if a query has predicates c1=1 and c2=1 and if there are statistics on (c1, c2), the optimizer will use this statistics for estimating the combined selectivity of the predicates.The expression statistics are used by optimizer for estimating selectivity of predicates on those expressions. The extended statistics are similar to column statistics and the procedures that take columns names will accept extension names in place of column names.

Related subprograms:


Deprecated Subprograms

The following subprograms are obsolete with Release 11g:


Examples

Using Pending Statistics

Assume many modifications have been made to the employees table since the last time statistics were gathered. To ensure that the cost-based optimizer is still picking the best plan, statistics should be gathered once again; however, the user is concerned that new statistics will cause the optimizer to choose bad plans when the current ones are acceptable. The user can do the following:

EXEC DBMS_STATS.SET_TABLE_PREFS('hr', 'employees', 'PUBLISH', 'false');

By setting the employees tables publish preference to FALSE, any statistics gather from now on will not be automatically published. The newly gathered statistics will be marked as pending.

EXEC DBMS_STATS.GATHER_TABLE_STATS ('hr', 'employees');

To test the newly gathered statistics, set optimizer_pending_statistics to TRUE in a session and run sample queries.

ALTER SESSION SET optimizer_use_pending_statistics = TRUE;

If the pending statistics generate sound execution plans, they can be published:

EXEC DBMS_STATS.PUBLISH_PENDING_STATS('hr', 'employees');
EXEC DBMS_STATS.SET_TABLE_PREF('hr', 'employees', 'PUBLISH', 'true'); 

Gathering Daytime System Statistics

Assume that you want to perform database application processing OLTP transactions during the day and run reports at night.

To collect daytime system statistics, gather statistics for 720 minutes. Store the statistics in the MYSTATS table.

BEGIN
   DBMS_STATS.GATHER_SYSTEM_STATS (
      interval => 720,
      stattab  => 'mystats',
      statid   => 'OLTP');
END;

To collect nighttime system statistics, gather statistics for 720 minutes. Store the statistics in the MYSTATS table.

BEGIN
   DBMS_STATS.GATHER_SYSTEM_STATS (
      interval => 720,
      stattab  => 'mystats',
      statid   => 'OLAP');
END;

Update the dictionary with the gathered statistics.

VARIABLE   jobno   number;
BEGIN
   DBMS_JOB.SUBMIT (:jobno, 'DBMS_STATS.IMPORT_SYSTEM_STATS
   (''mystats'',''OLTP'');'
   sysdate, 'sysdate + 1');
   COMMIT;
END;

BEGIN
   DBMS_JOB.SUBMIT (:jobno, 'DBMS_STATS.IMPORT_SYSTEM_STATS
   (''mystats'',''OLAP'');'
   sysdate + 0.5, 'sysdate + 1');
   COMMIT;
END;

Summary of DBMS_STATS Subprograms

Table 140-2 DBMS_STATS Package Subprograms

Subprogram Description

ALTER_STATS_HISTORY_RETENTION Procedure

Changes the statistics history retention value

CONVERT_RAW_VALUE Procedures

Convert the internal representation of a minimum or maximum value into a datatype-specific value

CONVERT_RAW_VALUE_NVARCHAR Procedure

Convert the internal representation of a minimum or maximum value into a datatype-specific value

CONVERT_RAW_VALUE_ROWID Procedure

Convert the internal representation of a minimum or maximum value into a datatype-specific value

COPY_TABLE_STATS Procedure

Copies the statistics of the source [sub] partition to the destination [sub] partition after scaling

CREATE_EXTENDED_STATS Function

Creates a virtual column for a user specified column group or an expression in a table

CREATE_STAT_TABLE Procedure

Creates a table with name stattab in ownname's schema which is capable of holding statistics

DELETE_COLUMN_STATS Procedure

Deletes column-related statistics

DELETE_DATABASE_PREFS Procedure

Deletes the statistics preferences of all the tables, excluding the tables owned by Oracle

DELETE_DATABASE_STATS Procedure

Deletes statistics for the entire database

DELETE_DICTIONARY_STATS Procedure

Deletes statistics for all dictionary schemas ('SYS', 'SYSTEM' and RDBMS component schemas)

DELETE_FIXED_OBJECTS_STATS Procedure

Deletes statistics of all fixed tables

DELETE_INDEX_STATS Procedure

Deletes index-related statistics

DELETE_PENDING_STATS Procedure

Deletes the private statistics that have been collected but have not been published

DELETE_SCHEMA_PREFS Procedure

Deletes the statistics preferences of all the tables owned by the specified owner name

DELETE_SCHEMA_STATS Procedure

Deletes schema-related statistics

DELETE_SYSTEM_STATS Procedure

Deletes system statistics

DELETE_TABLE_PREFS Procedure

Deletes statistics preferences of the specified table in the specified schema

DELETE_TABLE_STATS Procedure

Deletes table-related statistics

DIFF_TABLE_STATS_IN_HISTORY Function

Compares statistics for a table from two timestamps in past and compare the statistics as of that timestamps

DIFF_TABLE_STATS_IN_PENDING Function

Compares pending statistics and statistics as of a timestamp or statistics from dictionary

DIFF_TABLE_STATS_IN_STATTAB Function

Compares statistics for a table from two different sources

DROP_EXTENDED_STATS Procedure

Drops the statistics entry that is created for the user specified extension

DROP_STAT_TABLE Procedure

Drops a user statistics table created by CREATE_STAT_TABLE

EXPORT_COLUMN_STATS Procedure

Retrieves statistics for a particular column and stores them in the user statistics table identified by stattab

EXPORT_DATABASE_PREFS Procedure

Exports the statistics preferences of all the tables, excluding the tables owned by Oracle

EXPORT_DATABASE_STATS Procedure

Retrieves statistics for all objects in the database and stores them in the user statistics table identified by statown.stattab

EXPORT_DICTIONARY_STATS Procedure

Retrieves statistics for all dictionary schemas ('SYS', 'SYSTEM' and RDBMS component schemas) and stores them in the user statistics table identified by stattab

EXPORT_FIXED_OBJECTS_STATS Procedure

Retrieves statistics for fixed tables and stores them in the user statistics table identified by stattab

EXPORT_INDEX_STATS Procedure

Retrieves statistics for a particular index and stores them in the user statistics table identified by stattab

EXPORT_PENDING_STATS Procedure

Exports the statistics gathered and stored as pending

EXPORT_SCHEMA_PREFS Procedure

Exports the statistics preferences of all the tables owned by the specified owner name

EXPORT_SCHEMA_STATS Procedure

Retrieves statistics for all objects in the schema identified by ownname and stores them in the user statistics table identified by stattab

EXPORT_SYSTEM_STATS Procedure

Retrieves system statistics and stores them in the user statistics table

EXPORT_TABLE_PREFS Procedure

Exports statistics preferences of the specified table in the specified schema into the specified statistics table

EXPORT_TABLE_STATS Procedure

Retrieves statistics for a particular table and stores them in the user statistics table

FLUSH_DATABASE_MONITORING_INFO Procedure

Flushes in-memory monitoring information for all the tables to the dictionary

GATHER_DATABASE_STATS Procedures

Gathers statistics for all objects in the database

GATHER_DICTIONARY_STATS Procedure

Gathers statistics for dictionary schemas 'SYS', 'SYSTEM' and schemas of RDBMS components

GATHER_FIXED_OBJECTS_STATS Procedure

Gathers statistics of fixed objects

GATHER_INDEX_STATS Procedure

Gathers index statistics

GATHER_SCHEMA_STATS Procedures

Gathers statistics for all objects in a schema

GATHER_SYSTEM_STATS Procedure

Gathers system statistics

GATHER_TABLE_STATS Procedure

Gathers table and column (and index) statistics

GENERATE_STATS Procedure

Generates object statistics from previously collected statistics of related objects

GET_COLUMN_STATS Procedures

Gets all column-related information

GET_INDEX_STATS Procedures

Gets all index-related information

GET_PARAM Function

Gets the default value of parameters of DBMS_STATS procedures [see Deprecated Subprograms ]

GET_PREFS Function

Gets the default value of the specified preference

GET_STATS_HISTORY_AVAILABILITY Function

Gets the oldest timestamp where statistics history is available

GET_STATS_HISTORY_RETENTION Function

Returns the current retention value

GET_SYSTEM_STATS Procedure

Gets system statistics from stattab, or from the dictionary if stattab is NULL

GET_TABLE_STATS Procedure

Gets all table-related information

IMPORT_COLUMN_STATS Procedure

Retrieves statistics for a particular column from the user statistics table identified by stattab and stores them in the dictionary

IMPORT_DATABASE_PREFS Procedure

Imports the statistics preferences of all the tables, excluding the tables owned by Oracle

IMPORT_DATABASE_STATS Procedure

Retrieves statistics for all objects in the database from the user statistics table and stores them in the dictionary

IMPORT_DICTIONARY_STATS Procedure

Retrieves statistics for all dictionary schemas ('SYS', 'SYSTEM' and RDBMS component schemas) from the user statistics table and stores them in the dictionary

IMPORT_FIXED_OBJECTS_STATS Procedure

Retrieves statistics for fixed tables from the user statistics table identified by stattab and stores them in the dictionary

IMPORT_INDEX_STATS Procedure

Retrieves statistics for a particular index from the user statistics table identified by stattab and stores them in the dictionary

IMPORT_SCHEMA_PREFS Procedure

Imports the statistics preferences of all the tables owned by the specified owner name

IMPORT_SCHEMA_STATS Procedure

Retrieves statistics for all objects in the schema identified by ownname from the user statistics table and stores them in the dictionary

IMPORT_SYSTEM_STATS Procedure

Retrieves system statistics from the user statistics table and stores them in the dictionary

IMPORT_TABLE_PREFS Procedure

Sets the statistics preferences of the specified table in the specified schema

IMPORT_TABLE_STATS Procedure

Retrieves statistics for a particular table from the user statistics table identified by stattab and stores them in the dictionary

LOCK_PARTITION_STATS Procedure

Locks statistics for a partition

LOCK_SCHEMA_STATS Procedure

Locks the statistics of all tables of a schema

LOCK_TABLE_STATS Procedure

Locks the statistics on the table

MERGE_COL_USAGE Procedure

Merges column usage information from a source database, by means of a dblink, into the local database

PREPARE_COLUMN_VALUES Procedures

Converts user-specified minimum, maximum, and histogram endpoint datatype-specific values into Oracle's internal representation for future storage using the SEED_COL_USAGE Procedure

PREPARE_COLUMN_VALUES_NVARCHAR2 Procedure

Converts user-specified minimum, maximum, and histogram endpoint datatype-specific values into Oracle's internal representation for future storage using the SEED_COL_USAGE Procedure

PREPARE_COLUMN_VALUES_ROWID Procedure

Converts user-specified minimum, maximum, and histogram endpoint datatype-specific values into Oracle's internal representation for future storage using the SEED_COL_USAGE Procedure

PUBLISH_PENDING_STATS Procedure

Publishes the statistics gathered and stored as pending

PURGE_STATS Procedure

Purges old versions of statistics saved in the dictionary

RESET_GLOBAL_PREF_DEFAULTS Procedure

Resets the default values of all parameters to Oracle recommended values

RESET_PARAM_DEFAULTS Procedure

Resets global preferences to default values [see Deprecated Subprograms ]

RESTORE_DICTIONARY_STATS Procedure

Restores statistics of all dictionary tables (tables of 'SYS', 'SYSTEM' and RDBMS component schemas) as of a specified timestamp

RESTORE_FIXED_OBJECTS_STATS Procedure

Restores statistics of all fixed tables as of a specified timestamp

RESTORE_SCHEMA_STATS Procedure

Restores statistics of all tables of a schema as of a specified timestamp

RESTORE_SYSTEM_STATS Procedure

Restores statistics of all tables of a schema as of a specified timestamp

RESTORE_TABLE_STATS Procedure

Restores statistics of a table as of a specified timestamp (as_of_timestamp), as well as statistics of associated indexes and columns

SEED_COL_USAGE Procedure

Iterates over the SQL statements in the specified SQL tuning set, compiles them and seeds column usage information for the columns that appear in these statements

SET_COLUMN_STATS Procedures

Sets column-related information

SET_DATABASE_PREFS Procedure

Sets the statistics preferences of all the tables, excluding the tables owned by Oracle

SET_GLOBAL_PREFS Procedure

Sets the global statistics preferences

SET_INDEX_STATS Procedures

Sets index-related information

SET_PARAM Procedure

Sets default values for parameters of DBMS_STATS procedures [see Deprecated Subprograms ]

SET_SCHEMA_PREFS Procedure

Sets the statistics preferences of all the tables owned by the specified owner name

SET_SYSTEM_STATS Procedure

Sets system statistics

SET_TABLE_PREFS Procedure

Sets the statistics preferences of the specified table in the specified schema

SET_TABLE_STATS Procedure

Sets table-related information

SHOW_EXTENDED_STATS_NAME Function

Returns the name of the virtual column that is created for the user-specified extension

UNLOCK_PARTITION_STATS Procedure

Unlocks the statistics for a partition

UNLOCK_SCHEMA_STATS Procedure

Unlocks the statistics on all the table in a schema

UNLOCK_TABLE_STATS Procedure

Unlocks the statistics on the table

UPGRADE_STAT_TABLE Procedure

Upgrades user statistics on an older table



ALTER_STATS_HISTORY_RETENTION Procedure

This procedure changes the statistics history retention value. Statistics history retention is used by both the automatic purge and PURGE_STATS Procedure.

Syntax

DBMS_STATS.ALTER_STATS_HISTORY_RETENTION (
   retention       IN     NUMBER);

Parameters

Table 140-3 ALTER_STATS_HISTORY_RETENTION Procedure Parameters

Parameter Description

retention

The retention time in days. The statistics history will be retained for at least these many number of days.The valid range is [1,365000]. Also you can use the following values for special purposes:

  • -1 :Statistics history is never purged by automatic purge

  • 0 : Old statistics are never saved. The automatic purge will delete all statistics history

  • NULL : Change statistics history retention to default value


Usage Notes

To run this procedure, you must have the SYSDBA or both ANALYZE ANY DICTIONARY and ANALYZE ANY system privilege.

Exceptions

ORA-20000: Insufficient privileges


CONVERT_RAW_VALUE Procedures

This procedure converts the internal representation of a minimum or maximum value into a datatype-specific value. The minval and maxval fields of the StatRec structure as filled in by GET_COLUMN_STATS or PREPARE_COLUMN_VALUES are appropriate values for input.

Syntax

DBMS_STATS.CONVERT_RAW_VALUE (
   rawval     RAW, 
   resval OUT BINARY_FLOAT);

DBMS_STATS.CONVERT_RAW_VALUE (
   rawval     RAW, 
   resval OUT BINARY_DOUBLE);

DBMS_STATS.CONVERT_RAW_VALUE (
   rawval     RAW, 
   resval OUT DATE);

DBMS_STATS.CONVERT_RAW_VALUE (
   rawval     RAW, 
   resval OUT NUMBER);

DBMS_STATS.CONVERT_RAW_VALUE (
   rawval     RAW, 
   resval OUT VARCHAR2);

Pragmas

pragma restrict_references(convert_raw_value, WNDS, RNDS, WNPS, RNPS);

Parameters

Table 140-4 CONVERT_RAW_VALUE Procedure Parameters

Parameter Description

rawval

The raw representation of a column minimum or maximum datatype-specific output parameters

resval

The converted, type-specific value



CONVERT_RAW_VALUE_NVARCHAR Procedure

This procedure converts the internal representation of a minimum or maximum value into a datatype-specific value. The minval and maxval fields of the StatRec structure as filled in by GET_COLUMN_STATS or PREPARE_COLUMN_VALUES are appropriate values for input.

Syntax

DBMS_STATS.CONVERT_RAW_VALUE_NVARCHAR (
   rawval     RAW, 
   resval OUT NVARCHAR2);

Pragmas

pragma restrict_references(convert_raw_value_nvarchar, WNDS, RNDS, WNPS, RNPS);

Parameters

Table 140-5 CONVERT_RAW_VALUE_NVARCHAR Procedure Parameters

Parameter Description

rawval

The raw representation of a column minimum or maximum datatype-specific output parameters

resval

The converted, type-specific value



CONVERT_RAW_VALUE_ROWID Procedure

This procedure converts the internal representation of a minimum or maximum value into a datatype-specific value. The minval and maxval fields of the StatRec structure as filled in by GET_COLUMN_STATS or PREPARE_COLUMN_VALUES are appropriate values for input.

Syntax

DBMS_STATS.CONVERT_RAW_VALUE_ROWID (
   rawval     RAW, 
   resval OUT ROWID);

Pragmas

pragma restrict_references(convert_raw_value_rowid, WNDS, RNDS, WNPS, RNPS);

Parameters

Table 140-6 CONVERT_RAW_VALUE_ROWID Procedure Parameters

Parameter Description

rawval

The raw representation of a column minimum or maximum datatype-specific output parameters

resval

The converted, type-specific value



COPY_TABLE_STATS Procedure

This procedure copies the statistics of the source [sub] partition to the destination [sub] partition after scaling (the number of blks, number of rows). It sets the high bound partitioning value as the maximum value of the first partitioning column and high bound partitioning value of the previous partition as the minimum value of the first partitioning column for a range partitioned table. It finds the maximum and minimum from the list of values for the list partitioned table. It also sets the normalized maximum and minimum values. If the destination partition is the first partition then minimum values are equal to maximum values. If the statistics for source are not available then nothing is copied.

Syntax

DBMS_STATS.COPY_TABLE_STATS (
   ownname          VARCHAR2, 
   tabname          VARCHAR2, 
   srcpartname      VARCHAR2,
   dstpartname      VARCHAR2, 
   scale_factor     VARCHAR2 DEFAULT 1,
   force            BOOLEAN DEFAULT FALSE);

Parameters

Table 140-7 COPY_TABLE_STATS Procedure Parameters

Parameter Description

ownname

Schema of the table of source and destination [sub] partitions

tabname

Table name of source and destination [sub] partitions

srcpartname

Source [sub] partition

dtspartname

Destination [sub] partition

scale_factor

Scale factor to scale nblks, nrows etc. in dstpartname

force

When value of this argument is TRUE, copy statistics even if locked


Exceptions

ORA-20000: Invalid partition name

ORA-20001: Bad input value


CREATE_EXTENDED_STATS Function

This function creates a column statistics entry in the system for a user specified column group or an expression in a table. Statistics for this extension will be gathered when user or auto statistics gathering job gathers statistics for the table. We call statistics for such an extension, "extended statistics". This function returns the name of this newly created entry for the extension.

Syntax

DBMS_STATS.CREATE_EXTENDED_STATS (
   ownname    VARCHAR2, 
   tabname    VARCHAR2,
   extension  VARCHAR2)
 RETURN VARCHAR2;

Parameters

Table 140-8 CREATE_EXTENDED_STATS Function Parameters

Parameter Description

ownname

Owner name of a table

tabname

Name of the table

extension

Can be either a column group or an expression. Suppose the specified table has two column c1, c2. An example column group can be "(c1, c2)" and an example expression can be "(c1 + c2)".


Return Values

This function returns the name of this newly created entry for the extension.

Exceptions

ORA-20000: Insufficient privileges / creating extension is not supported

ORA-20001: Error when processing extension

ORA-20007: Extension already exists

ORA-20008: Reached the upper limit on number of extensions

Usage Notes

There are nine restrictions on the extension:


CREATE_STAT_TABLE Procedure

This procedure creates a table with name stattab in ownname's schema which is capable of holding statistics. The columns and types that compose this table are not relevant as it should be accessed solely through the procedures in this package.

Syntax

DBMS_STATS.CREATE_STAT_TABLE (
   ownname  VARCHAR2, 
   stattab  VARCHAR2,
   tblspace VARCHAR2 DEFAULT NULL);

Parameters

Table 140-9 CREATE_STAT_TABLE Procedure Parameters

Parameter Description

ownname

Name of the schema

stattab

Name of the table to create. This value should be passed as the stattab parameter to other procedures when the user does not want to modify the dictionary statistics directly.

tblspace

Tablespace in which to create the statistics tables. If none is specified, then they are created in the user's default tablespace.


Exceptions

ORA-20000: Table already exists or insufficient privileges

ORA-20001: Tablespace does not exist


DELETE_COLUMN_STATS Procedure

This procedure deletes column-related statistics.

Syntax

DBMS_STATS.DELETE_COLUMN_STATS (
   ownname        VARCHAR2, 
   tabname        VARCHAR2, 
   colname        VARCHAR2, 
   partname       VARCHAR2 DEFAULT NULL,
   stattab        VARCHAR2 DEFAULT NULL, 
   statid         VARCHAR2 DEFAULT NULL,
   cascade_parts  BOOLEAN  DEFAULT TRUE,
   statown        VARCHAR2 DEFAULT NULL,
   no_invalidate  BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   force          BOOLEAN  DEFAULT FALSE,
   col_stat_type  VARCHAR2 DEFAULT 'ALL');

Parameters

Table 140-10 DELETE_COLUMN_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table to which this column belongs

colname

Name of the column or extension

partname

Name of the table partition for which to delete the statistics. If the table is partitioned and if partname is NULL, then global column statistics are deleted.

stattab

User statistics table identifier describing from where to delete the statistics. If stattab is NULL, then the statistics are deleted directly from the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL).

cascade_parts

If the table is partitioned and if partname is NULL, then setting this to true causes the deletion of statistics for this column for all underlying partitions as well.

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

When value of this argument is TRUE, deletes column statistics even if locked

col_stat_type

Type of column statistics to be deleted.This argument takes the following values:

  • HISTOGRAM - delete column histogram only

  • ALL - delete base column statistics and histogram


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20005: Object statistics are locked


DELETE_DATABASE_PREFS Procedure

This procedure is used to delete the statistics preferences of all the tables, excluding the tables owned by Oracle. These tables can by included by passing TRUE for the add_sys parameter.

Syntax

DBMS_STATS.DELETE_DATABASE_PREFS (
    pname            IN   VARCHAR2,
    add_sys          IN   BOOLEAN DEFAULT FALSE);

Parameters

Table 140-11 DELETE_DATABASE_PREFS Procedure Parameters

Parameter Description

pname

Preference name. The default value for following parameters can be deleted:

  • CASCADE

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • PUBLISH

  • INCREMENTAL

  • STALE_PERCENT

.

CASCADE - The value determines whether or not index statistics are collected as part of gathering table statistics

.

DEGREE - The value determines degree of parallelism used for gathering statistics

.

ESTIMATE_PERCENT - The value determines the percentage of rows to estimate. The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.

.

METHOD_OPT - The value controls column statistics collection and histogram creation. It accepts either of the following options, or both in combination:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns
- column_name : name of a column
- extension : can be either a column group in the format of (column_name, colume_name [, ...]) or an expression

The default is FOR ALL COLUMNS SIZE AUTO.

.

NO_INVALIDATE - The value controls the invalidation of dependent cursors of the tables for which statistics are being gathered. Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE to have Oracle decide when to invalidate dependent cursors. This is the default.

.

GRANULARITY - The value determines granularity of statistics to collect (only pertinent if the table is partitioned)

'ALL' - gathers all (subpartition, partition, and global) statistics

'AUTO'- determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - gathers global statistics

'GLOBAL AND PARTITION' - gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- gathers partition-level statistics

'SUBPARTITION' - gathers subpartition-level statistics

.

PUBLISH - This value determines whether or not newly gathered statistics will be published once the gather job has completed. Prior to Oracle Database 11g, Release 1 (11.1), once a statistic gathering job completed the new statistics were automatically published into the dictionary tables. The user now has the ability to gather statistics but not publish them immediately. This allows the DBA to test the new statistics before publishing them.

.

INCREMENTAL - This value determines whether or not the global statistics of a partitioned table will be maintained without doing a full table scan. With partitioned tables it is very common to load new data into a new partition. As new partitions are added and data loaded, the global table statistics need to be kept up to date. Oracle will update the global table statistics by scanning only the partitions that have been changed instead of the entire table if the following conditions hold:

  • the INCREMENTAL value for the partitioned table is set to TRUE;

  • the PUBLISH value for the partitioned table is set to TRUE;

  • the user specifies AUTO_SAMPLE_SIZE for ESTIMATE_PERCENT and AUTO for GRANULARITY when gathering statistics on the table.

If the INCREMENTAL value for the partitioned table was set to FALSE (default value), a full table scan is used to maintain the global statistics which is a much more resource intensive and time-consuming operation for large tables.

.

STALE_PERCENT - This value determines the percentage of rows in a table that have to change before the statistics on that table are deemed stale and should be regathered. The default value is 10%.

add_sys

Value TRUE will include the Oracle-owned tables


Exceptions

ORA-20000: Insufficient privileges

ORA-20001: Invalid or Illegal input values

Usage Notes

Examples

DBMS_STATS.DELETE_DATABASE_PREFS('CASCADE', FALSE);
DBMS_STATS.DELETE_DATABASE_PREFS('ESTIMATE_PERCENT',TRUE);

DELETE_DATABASE_STATS Procedure

This procedure deletes statistics for all the tables in a database.

Syntax

DBMS_STATS.DELETE_DATABASE_STATS (
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   statown          VARCHAR2 DEFAULT NULL,
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   force            BOOLEAN  DEFAULT FALSE);

Parameters

Table 140-12 DELETE_DATABASE_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing from where to delete the statistics. If stattab is NULL, then the statistics are deleted directly in the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

statown

Schema containing stattab (if different from current schema)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

When the value of this argument is TRUE, deletes statistics of tables in a database even if they are locked


Exceptions

ORA-20000: Object does not exist or insufficient privileges


DELETE_DICTIONARY_STATS Procedure

This procedure deletes statistics for all dictionary schemas ('SYS', 'SYSTEM' and RDBMS component schemas).

Syntax

DBMS_STATS.DELETE_DICTIONARY_STATS (
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   statown          VARCHAR2 DEFAULT NULL,
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   force            BOOLEAN  DEFAULT FALSE);

Parameters

Table 140-13 DELETE_DICTIONARY_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing from where to delete the statistics. If stattab is NULL, then the statistics are deleted directly in the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

statown

Schema containing stattab (if different from current schema)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure

force

When the value of this argument is TRUE, deletes statistics of tables in a database even if they are locked


Usage Notes

You must have the SYSDBA or both ANALYZE ANY DICTIONARY and ANALYZE ANY system privilege to execute this procedure.

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20002: Bad user statistics table, may need to upgrade it


DELETE_FIXED_OBJECTS_STATS Procedure

This procedure deletes statistics of all fixed tables.

Syntax

DBMS_STATS.DELETE_FIXED_OBJECTS_STATS (
   stattab        VARCHAR2 DEFAULT NULL,
   statid         VARCHAR2 DEFAULT NULL,
   statown        VARCHAR2 DEFAULT NULL, 
   no_invalidate  BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   force          BOOLEAN  DEFAULT FALSE); 

Parameters

Table 140-14 DELETE_FIXED_OBJECTS_STATS Procedure Parameters

Parameter Description

stattab

The user statistics table identifier describing from where to delete the current statistics. If stattab is NULL, the statistics will be deleted directly in the dictionary.

statid

The (optional) identifier to associate with these statistics within stattab. This only applies if stattab is not NULL.

statown

Schema containing stattab (if different from current schema)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure

force

Ignores the statistics lock on objects and deletes the statistics if set to TRUE


Usage Notes

You must have the SYSDBA or ANALYZE ANY DICTIONARY system privilege to execute this procedure.

Exceptions

ORA-20000: Insufficient privileges

ORA-20002: Bad user statistics table, may need to upgrade it


DELETE_INDEX_STATS Procedure

This procedure deletes index-related statistics.

Syntax

DBMS_STATS.DELETE_INDEX_STATS (
   ownname          VARCHAR2, 
   indname          VARCHAR2,
   partname         VARCHAR2 DEFAULT NULL,
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   cascade_parts    BOOLEAN  DEFAULT TRUE,
   statown          VARCHAR2 DEFAULT NULL,
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   force            BOOLEAN DEFAULT FALSE);

Parameters

Table 140-15 DELETE_INDEX_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

indname

Name of the index

partname

Name of the index partition for which to delete the statistics. If the index is partitioned and if partname is NULL, then index statistics are deleted at the global level.

stattab

User statistics table identifier describing from where to delete the statistics. If stattab is NULL, then the statistics are deleted directly from the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

cascade_parts

If the index is partitioned and if partname is NULL, then setting this to TRUE causes the deletion of statistics for this index for all underlying partitions as well

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

When value of this argument is TRUE, deletes index statistics even if locked


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20005: Object statistics are locked


DELETE_PENDING_STATS Procedure

This procedure is used to delete the pending statistics that have been collected but have not been published.

Syntax

DBMS_STATS.DELETE_PENDING_STATS (
    ownname    IN  VARCHAR2  DEFAULT USER,
    tabname    IN  VARCHAR2);

Parameters

Table 140-16 DELETE_PENDING_STATS Procedure Parameters

Parameter Description

ownname

Owner name

tabname

Table name


Exceptions

ORA-20000: Insufficient privileges

Usage Notes

Examples

DBMS_STATS.DELETE_PENDING_STATS('SH', 'SALES');

DELETE_SCHEMA_PREFS Procedure

This procedure is used to delete the statistics preferences of all the tables owned by the specified owner name.

Syntax

DBMS_STATS.DELETE_SCHEMA_PREFS (
    ownname   IN   VARCHAR2,
    pname     IN   VARCHAR2);

Parameters

Table 140-17 DELETE_SCHEMA_PREFS Procedure Parameters

Parameter Description

ownname

Owner name

pname

Preference name. The default value for following parameters can be deleted:

  • CASCADE

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • PUBLISH

  • INCREMENTAL

  • STALE_PERCENT

.

CASCADE - Determines whether or not index statistics are collected as part of gathering table statistics

.

DEGREE - Determines degree of parallelism used for gathering statistics

.

ESTIMATE_PERCENT - Determines the percentage of rows to estimate. The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.

.

METHOD_OPT - Controls column statistics collection and histogram creation. It accepts either of the following options, or both in combination:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns
- column_name : name of a column
- extension: can be either a column group in the format of (column_name, colume_name [, ...])or an expression

The default is FOR ALL COLUMNS SIZE AUTO.

.

NO_INVALIDATE - Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

.

GRANULARITY - The value determines granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - gathers all (subpartition, partition, and global) statistics

'AUTO'- determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - gathers global statistics

'GLOBAL AND PARTITION' - gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- gathers partition-level statistics

'SUBPARTITION' - gathers subpartition-level statistics.

.

PUBLISH - This value determines whether or not newly gathered statistics will be published once the gather job has completed. Prior to Oracle Database 11g, Release 1 (11.1), once a statistic gathering job completed the new statistics were automatically published into the dictionary tables. The user now has the ability to gather statistics but not publish them immediately. This allows the DBA to test the new statistics before publishing them.

.

INCREMENTAL - This value determines whether or not the global statistics of a partitioned table will be maintained without doing a full table scan. With partitioned tables it is very common to load new data into a new partition. As new partitions are added and data loaded, the global table statistics need to be kept up to date. Oracle will update the global table statistics by scanning only the partitions that have been changed instead of the entire table if the following conditions hold:

  • the INCREMENTAL value for the partitioned table is set to TRUE

  • the PUBLISH value for the partitioned table is set to TRUE

  • the user specifies AUTO_SAMPLE_SIZE for ESTIMATE_PERCENT and AUTO for GRANULARITY when gathering statistics on the table

If the INCREMENTAL value for the partitioned table was set to FALSE (default value), a full table scan is used to maintain the global statistics which is a much more resource intensive and time-consuming operation for large tables.

.

STALE_PERCENT - This value determines the percentage of rows in a table that have to change before the statistics on that table are deemed stale and should be regathered. The default value is 10%.


Exceptions

ORA-20000: Insufficient privileges / Schema "<schema>" does not exist

ORA-20001: Invalid or Illegal input values

Usage Notes

Examples

DBMS_STATS.DELETE_SCHEMA_PREFS('SH', 'CASCADE');
DBMS_STATS.DELETE_SCHEMA_PREFS('SH', 'ESTIMATE_PERCENT');
DBMS_STATS.DELETE_SCHEMA_PREFS('SH', 'DEGREE');

DELETE_SCHEMA_STATS Procedure

This procedure deletes statistics for an entire schema.

Syntax

DBMS_STATS.DELETE_SCHEMA_STATS (
   ownname          VARCHAR2, 
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   statown          VARCHAR2 DEFAULT NULL,
   no_invalidate    BOOLEAN DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   force            BOOLEAN DEFAULT FALSE);

Parameters

Table 140-18 DELETE_SCHEMA_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

stattab

User statistics table identifier describing from where to delete the statistics. If stattab is NULL, then the statistics are deleted directly in the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

When value of this argument is TRUE, deletes statistics of tables in a schema even if locked


Exceptions

ORA-20000: Object does not exist or insufficient privileges


DELETE_SYSTEM_STATS Procedure

This procedure deletes workload statistics (collected using the 'INTERVAL' or 'START' and 'STOP' options) and resets the default to noworkload statistics (collected using 'NOWORKLOAD' option) if stattab is not specified. If stattab is specified, the subprogram deletes all system statistics with the associated statid from the stattab.

Syntax

DBMS_STATS.DELETE_SYSTEM_STATS (
   stattab       VARCHAR2 DEFAULT NULL, 
   statid        VARCHAR2 DEFAULT NULL,
   statown       VARCHAR2 DEFAULT NULL);

Parameters

Table 140-19 DELETE_SYSTEM_STATS Procedure Parameters

Parameter Description

stattab

Identifier of the user statistics table where the statistics will be saved

statid

Optional identifier associated with the statistics saved in the stattab

statown

Schema containing stattab (if different from current schema)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20002: Bad user statistics table; may need to be upgraded


DELETE_TABLE_PREFS Procedure

This procedure is used to delete the statistics preferences of the specified table in the specified schema.

Syntax

DBMS_STATS.DELETE_TABLE_PREFS (
    ownname    IN  VARCHAR2,    tabname    IN  VARCHAR2,    pname      IN  VARCHAR2);

Parameters

Table 140-20 DELETE_TABLE_PREFS Procedure Parameters

Parameter Description

ownname

Owner name

tabname

Table name

pname

Preference name. The default value for following preferences can be deleted:

  • CASCADE

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • PUBLISH

  • INCREMENTAL

  • STALE_PERCENT

.

CASCADE - Determines whether or not index statistics are collected as part of gathering table statistics

.

DEGREE - Determines degree of parallelism used for gathering statistics

.

ESTIMATE_PERCENT - Determines the percentage of rows to estimate. The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.

.

METHOD_OPT - The value controls column statistics collection and histogram creation. It accepts either of the following options, or both in combination:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms.
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.
- column_name : name of a column
- extension : can be either a column group in the format of (column_name, colume_name [, ...]) or an expression

The default is FOR ALL COLUMNS SIZE AUTO.

.

NO_INVALIDATE - Controls the invalidation of dependent cursors of the tables for which statistics are being gathered. Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE to have Oracle decide when to invalidate dependent cursors. This is the default.

.

GRANULARITY - Determines granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - Gathers subpartition-level statistics.

.

PUBLISH - Determines whether or not newly gathered statistics will be published once the gather job has completed. Prior to Oracle Database 11g, Release 1 (11.1), once a statistic gathering job completed the new statistics were automatically published into the dictionary tables. The user now has the ability to gather statistics but not publish them immediately. This allows the DBA to test the new statistics before publishing them.

.

INCREMENTAL - Determines whether or not the global statistics of a partitioned table will be maintained without doing a full table scan. With partitioned tables it is very common to load new data into a new partition. As new partitions are added and data loaded, the global table statistics need to be kept up to date. Oracle will update the global table statistics by scanning only the partitions that have been changed instead of the entire table if the following conditions hold:

  • INCREMENTAL value for the partitioned table is set to TRUE

  • PUBLISH value for the partitioned table is set to TRUE;

  • User specifies AUTO_SAMPLE_SIZE for ESTIMATE_PERCENT and AUTO for GRANULARITY when gathering statistics on the table.

If the INCREMENTAL value for the partitioned table was set to FALSE (default value), a full table scan is used to maintain the global statistics which is a much more resource intensive and time-consuming operation for large tables.

.

STALE_PERCENT - Determines the percentage of rows in a table that have to change before the statistics on that table are deemed stale and should be regathered. The default value is 10%.

pvalue

Preference value. If NULL is specified, it will set the Oracle default value.


Exceptions

ORA-20000: Insufficient privileges

ORA-20001: Invalid or Illegal input values

Usage Notes

Examples

DBMS_STATS.DELETE_TABLE_PREFS('SH', 'SALES', 'CASCADE');
DBMS_STATS.DELETE_TABLE_PREFS('SH', 'SALES', 'DEGREE');

DELETE_TABLE_STATS Procedure

This procedure deletes table-related statistics.

Syntax

DBMS_STATS.DELETE_TABLE_STATS (
   ownname          VARCHAR2, 
   tabname          VARCHAR2, 
   partname         VARCHAR2 DEFAULT NULL,
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   cascade_parts    BOOLEAN  DEFAULT TRUE, 
   cascade_columns  BOOLEAN  DEFAULT TRUE,
   cascade_indexes  BOOLEAN  DEFAULT TRUE,
   statown          VARCHAR2 DEFAULT NULL,
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   force            BOOLEAN DEFAULT FALSE);

Parameters

Table 140-21 DELETE_TABLE_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table to which this column belongs

partname

Name of the table partition from which to get the statistics. If the table is partitioned and if partname is NULL, then the statistics are retrieved from the global table level.

stattab

User statistics table identifier describing from where to retrieve the statistics. If stattab is NULL, then the statistics are retrieved directly from the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

cascade_parts

If the table is partitioned and if partname is NULL, then setting this to TRUE causes the deletion of statistics for this table for all underlying partitions as well

cascade_columns

Indicates that DELETE_COLUMN_STATS should be called for all underlying columns (passing the cascade_parts parameter)

cascade_indexes

Indicates that DELETE_INDEX_STATS should be called for all underlying indexes (passing the cascade_parts parameter)

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

When value of this argument is TRUE, deletes table statistics even if locked


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20002: Bad user statistics table, may need to upgrade it

ORA-20005: Object statistics are locked


DIFF_TABLE_STATS_IN_HISTORY Function

This function can be used to compare statistics for a table from two timestamps in past and compare the statistics as of that timestamps.

Syntax

DBMS_STATS.DIFF_TABLE_STATS_IN_HISTORY( 
      ownname        IN  VARCHAR2,      tabname        IN  VARCHAR2,      time1          IN  TIMESTAMP WITH TIME ZONE,      time2          IN  TIMESTAMP WITH TIME ZONE DEFAULT NULL,      pctthreshold   IN  NUMBER  DEFAULT 10)   RETURN DiffRepTab pipelined;

Parameters

Table 140-22 DIFF_TABLE_STATS_IN_HISTORY Function Parameters

Parameter Description

ownname

Owner of the table. Specify NULL for current schema.

tabname

Table for which statistics are to be compared

time1

First timestamp 1

time2

Second timestamp 2

pctthreshold

The function reports difference in statistics only if it exceeds this limit. The default value is 10.


Usage Notes

If the second timestamp is NULL, the function compares the current statistics in dictionary with the statistics as of the other timestamp.


DIFF_TABLE_STATS_IN_PENDING Function

This function compares pending statistics and statistics as of a timestamp or statistics from dictionary.

Syntax

DBMS_STATS.DIFF_TABLE_STATS_IN_PENDING( 
      ownname        IN  VARCHAR2,      tabname        IN  VARCHAR2,      timestamp      IN  TIMESTAMP WITH TIME ZONE,      pctthreshold   IN  NUMBER  DEFAULT 10)   RETURN DiffRepTab pipelined;

Parameters

Table 140-23 DIFF_TABLE_STATS_IN_PENDING Function Parameters

Parameter Description

ownname

Owner of the table. Specify NULL for current schema.

tabname

Table for which statistics are to be compared

timestamp

Time stamp to get statistics from the history

pctthreshold

The function reports difference in statistics only if it exceeds this limit. The default value is 10.


Usage Notes

If the second timestamp is NULL, the function compares the current statistics in dictionary with the statistics as of the other timestamp.


DIFF_TABLE_STATS_IN_STATTAB Function

This function can be used to compare statistics for a table from two different sources. The statistics can be drawn from

The function also compares the statistics of the dependent objects (indexes, columns, partitions) as well. It displays statistics of the object(s) from both sources if the difference between those statistics exceeds a certain threshold (%). The threshold can be specified as an argument to the function. The statistics corresponding to the first source (stattab1 or time1) will be used as basis for computing the difference percentage.

Syntax

DBMS_STATS.DIFF_TABLE_STATS_IN_STATTAB( 
      ownname        IN  VARCHAR2,      tabname        IN  VARCHAR2,      stattab1       IN  VARCHAR2,      stattab2       IN  VARCHAR2 DEFAULT NULL,      pctthreshold   IN  NUMBER  DEFAULT 10,      statid1        IN  VARCHAR2 DEFAULT NULL,      statid2        IN  VARCHAR2 DEFAULT NULL,      stattab1own    IN  VARCHAR2 DEFAULT NULL,      stattab2own    IN  VARCHAR2 DEFAULT NULL)   RETURN DiffRepTab pipelined;

Parameters

Table 140-24 DIFF_TABLE_STATS_IN_STATTAB Function Parameters

Parameter Description

ownname

Owner of the table. Specify NULL for current schema.

tabname

Table for which statistics are to be compared

stattab1

User statistics table 1

stattab2

User statistics table 2. If NULL, statistics in stattab1 is compared with current statistics in dictionary. This is the default. Specify same table as stattab1 to compare two sets within the statistics table (see statid below).

pctthreshold

The function reports difference in statistics only if it exceeds this limit. The default value is 10.

stadid1

(optional) Identifies statistics set within stattab1.

stadid2

(optional) Identifies statistics set within stattab2

stattab1own

Schema containing stattab1 (if other than ownname)

stattab2own

Schema containing stattab2 (if other than ownname)



DROP_EXTENDED_STATS Procedure

This function drops the statistics entry that is created for the user specified extension. This cancels the effects of the CREATE_EXTENDED_STATS Function.

Syntax

DBMS_STATS.DROP_EXTENDED_STATS (
   ownname    VARCHAR2, 
   tabname    VARCHAR2,
   extension  VARCHAR2);

Parameters

Table 140-25 DROP_EXTENDED_STATS Procedure Parameters

Parameter Description

ownname

Owner name of a table

tabname

Name of the table

extension

Can be either a column group or an expression. Suppose the specified table has two column c1, c2. An example column group can be "(c1, c2)" and an example expression can be "(c1 + c2)".


Usage Notes

If no extended statistics set is created for the extension, this function throws an error.

Exceptions


DROP_STAT_TABLE Procedure

This procedure drops a user statistics table.

Syntax

DBMS_STATS.DROP_STAT_TABLE (
   ownname VARCHAR2, 
   stattab VARCHAR2);

Parameters

Table 140-26 DROP_STAT_TABLE Procedure Parameters

Parameter Description

ownname

Name of the schema

stattab

User statistics table identifier


Exceptions

ORA-20000: Table does not exists or insufficient privileges.


EXPORT_COLUMN_STATS Procedure

This procedure retrieves statistics for a particular column and stores them in the user statistics table identified by stattab.

Syntax

DBMS_STATS.EXPORT_COLUMN_STATS (
   ownname  VARCHAR2, 
   tabname  VARCHAR2, 
   colname  VARCHAR2, 
   partname VARCHAR2 DEFAULT NULL,
   stattab  VARCHAR2, 
   statid   VARCHAR2 DEFAULT NULL,
   statown  VARCHAR2 DEFAULT NULL);

Parameters

Table 140-27 EXPORT_COLUMN_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table to which this column belongs

colname

Name of the column or extension

partname

Name of the table partition. If the table is partitioned and if partname is NULL, then global and partition column statistics are exported.

stattab

User statistics table identifier describing where to store the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


EXPORT_DATABASE_PREFS Procedure

This procedure is used to export the statistics preferences of all the tables, excluding the tables owned by Oracle. These tables can by included by passing TRUE for the add_sys parameter.

Syntax

DBMS_STATS.EXPORT_DATABASE_PREFS (
    stattab    IN  VARCHAR2,
    statid     IN  VARCHAR2 DEFAULT NULL,
    statown    IN  VARCHAR2 DEFAULT NULL
    add_sys    IN  BOOLEAN DEFAULT FALSE);

Parameters

Table 140-28 EXPORT_DATABASE_PREFS Procedure Parameters

Parameter Description

stattab

Statistics table name to where statistics should be exported

statid

(Optional) Identifier to associate with these statistics within stattab

statown

Schema containing stattab (if other than ownname)

add_sys

Value TRUE will include the Oracle-owned tables


Exceptions

ORA-20000: Insufficient privileges

Usage Notes

Examples

DBMS_STATS.EXPORT_DATABASE_PREFS('STATTAB', statown=>'SH');

EXPORT_DATABASE_STATS Procedure

This procedure retrieves statistics for all objects in the database and stores them in the user statistics tables identified by statown.stattab.

Syntax

DBMS_STATS.EXPORT_DATABASE_STATS (
   stattab         VARCHAR2, 
   statid          VARCHAR2 DEFAULT NULL,
   statown         VARCHAR2 DEFAULT NULL,
   stat_category   VARCHAR2 DEFAULT DEFAULT_STAT_CATEGORY);

Parameters

Table 140-29 EXPORT_DATABASE_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing where to store the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different from current schema)

stat_category

Specifies what statistics to import, accepting multiple values separated by a comma. Values supported:

  • 'OBJECT_STATS' - table statistics, column statistics and index statistics (Default)

  • 'SYNOPSES' - auxiliary statistics information gathered on a partitioned table when incremental is TRUE


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


EXPORT_DICTIONARY_STATS Procedure

This procedure retrieves statistics for all dictionary schemas ('SYS', 'SYSTEM' and RDBMS component schemas) and stores them in the user statistics table identified by stattab.

Syntax

DBMS_STATS.EXPORT_DICTIONARY_STATS (
   stattab         VARCHAR2, 
   statid          VARCHAR2 DEFAULT NULL,
   statown         VARCHAR2 DEFAULT NULL,
   stat_category   VARCHAR2 DEFAULT DEFAULT_STAT_CATEGORY);

Parameters

Table 140-30 EXPORT_DICTIONARY_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing where to store the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different from current schema)

stat_category

Specifies what statistics to import, accepting multiple values separated by a comma. Values supported:

  • 'OBJECT_STATS' - table statistics, column statistics and index statistics (Default)

  • 'SYNOPSES' - auxiliary statistics information gathered on a partitioned table when incremental is TRUE


Usage Notes

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20002: Bad user statistics table, may need to upgrade it


EXPORT_FIXED_OBJECTS_STATS Procedure

This procedure retrieves statistics for fixed tables and stores them in the user statistics table identified by stattab.

Syntax

DBMS_STATS.EXPORT_FIXED_OBJECTS_STATS (
   stattab  VARCHAR2, 
   statid   VARCHAR2 DEFAULT NULL,
   statown  VARCHAR2 DEFAULT NULL);

Parameters

Table 140-31 EXPORT_FIXED_OBJECTS_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing where to store the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different from current schema)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20002: Bad user statistics table, may need to upgrade it

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


EXPORT_INDEX_STATS Procedure

This procedure retrieves statistics for a particular index and stores them in the user statistics table identified by stattab.

Syntax

DBMS_STATS.EXPORT_INDEX_STATS (
   ownname  VARCHAR2, 
   indname  VARCHAR2, 
   partname VARCHAR2 DEFAULT NULL,
   stattab  VARCHAR2, 
   statid   VARCHAR2 DEFAULT NULL,
   statown  VARCHAR2 DEFAULT NULL);

Parameters

Table 140-32 EXPORT_INDEX_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

indname

Name of the index

partname

Name of the index partition. If the index is partitioned and if partname is NULL, then global and partition index statistics are exported.

stattab

User statistics table identifier describing where to store the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


EXPORT_PENDING_STATS Procedure

This procedure is used to export the statistics gathered and stored as pending.

Syntax

DBMS_STATS.EXPORT_PENDING_STATS (
    ownname    IN  VARCHAR2  DEFAULT USER,
    tabname    IN  VARCHAR2,
    stattab    IN  VARCHAR2,
    statid     IN  VARCHAR2 DEFAULT NULL,
    statown    IN  VARCHAR2 DEFAULT USER);

Parameters

Table 140-33 EXPORT_PENDING_STATS Procedure Parameters

Parameter Description

ownname

Owner name

tabname

Table name

stattab

Statistics table name to where to export the statistics

statid

(Optional) Identifier to associate with these statistics within stattab

statown

Schema containing stattab (if other than ownname)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Examples

DBMS_STATS.EXPORT_PENDING_STATS(NULL, NULL, 'MY_STAT_TABLE');

EXPORT_SCHEMA_PREFS Procedure

This procedure is used to export the statistics preferences of all the tables owned by the specified owner name.

Syntax

DBMS_STATS.EXPORT_SCHEMA_PREFS (
    ownname    IN  VARCHAR2,
    stattab    IN  VARCHAR2,    statid     IN  VARCHAR2 DEFAULT NULL,
    statown    IN  VARCHAR2 DEFAULT NULL);

Parameters

Table 140-34 EXPORT_SCHEMA_PREFS Procedure Parameters

Parameter Description

ownname

Owner name

stattab

Statistics table name to where to export the statistics

statid

(Optional) Identifier to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Examples

DBMS_STATS.EXPORT_SCHEMA_PREFS('SH', 'STAT');

EXPORT_SCHEMA_STATS Procedure

This procedure retrieves statistics for all objects in the schema identified by ownname and stores them in the user statistics tables identified by stattab.

Syntax

DBMS_STATS.EXPORT_SCHEMA_STATS (
   ownname         VARCHAR2,
   stattab         VARCHAR2, 
   statid          VARCHAR2 DEFAULT NULL,
   statown         VARCHAR2 DEFAULT NULL,
   stat_category   VARCHAR2 DEFAULT DEFAULT_STAT_CATEGORY);

Parameters

Table 140-35 EXPORT_SCHEMA_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

stattab

User statistics table identifier describing where to store the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)

stat_category

Specifies what statistics to import, accepting multiple values separated by a comma. Values supported:

  • 'OBJECT_STATS' - table statistics, column statistics and index statistics (Default)

  • 'SYNOPSES' - auxiliary statistics information gathered on a partitioned table when incremental is TRUE


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


EXPORT_SYSTEM_STATS Procedure

This procedure retrieves system statistics and stores them in the user statistics table, identified by stattab.

Syntax

DBMS_STATS.EXPORT_SYSTEM_STATS (
   stattab       VARCHAR2, 
   statid        VARCHAR2 DEFAULT NULL,
   statown       VARCHAR2 DEFAULT NULL);

Parameters

Table 140-36 EXPORT_SYSTEM_STATS Procedure Parameters

Parameter Description

stattab

Identifier of the user statistics table that describes where the statistics will be stored

statid

Optional identifier associated with the statistics stored from the stattab

statown

Schema containing stattab (if different from current schema)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20002: Bad user statistics table; may need to be upgraded

ORA-20003: Unable to export system statistics

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


EXPORT_TABLE_PREFS Procedure

This procedure is used to export the statistics preferences of the specified table in the specified schema into the specified statistics table.

Syntax

DBMS_STATS.EXPORT_TABLE_PREFS (
    ownname    IN  VARCHAR2,
    tabname    IN  VARCHAR2,
    stattab    IN  VARCHAR2,
    statid     IN  VARCHAR2 DEFAULT NULL,
    statown    IN  VARCHAR2 DEFAULT NULL);

Parameters

Table 140-37 EXPORT_TABLE_PREFS Procedure Parameters

Parameter Description

ownname

Owner name

tabname

Table name

stattab

Statistics table name where to export the statistics

statid

Optional identifier to associate with these statistics within stattab

statown

Schema containing stattab (if other than ownname)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Examples

DBMS_STATS.EXPORT_TABLE_PREFS('SH', 'SALES', 'STAT');

EXPORT_TABLE_STATS Procedure

This procedure retrieves statistics for a particular table and stores them in the user statistics table. Cascade results in all index statistics associated with the specified table being exported as well.

Syntax

DBMS_STATS.EXPORT_TABLE_STATS (
   ownname         VARCHAR2, 
   tabname         VARCHAR2, 
   partname        VARCHAR2 DEFAULT NULL,
   stattab         VARCHAR2, 
   statid          VARCHAR2 DEFAULT NULL,
   cascade         BOOLEAN  DEFAULT TRUE,
   statown         VARCHAR2 DEFAULT NULL,
   stat_category   VARCHAR2 DEFAULT DEFAULT_STAT_CATEGORY);

Parameters

Table 140-38 EXPORT_TABLE_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table

partname

Name of the table partition. If the table is partitioned and if partname is NULL, then global and partition table statistics are exported.

stattab

User statistics table identifier describing where to store the statistics

statid

Identifier (optional) to associate with these statistics within stattab

cascade

If true, then column and index statistics for this table are also exported

statown

Schema containing stattab (if different than ownname)

stat_category

Specifies what statistics to import, accepting multiple values separated by a comma. Values supported:

  • 'OBJECT_STATS' - table statistics, column statistics and index statistics (Default)

  • 'SYNOPSES' - auxiliary statistics information gathered on a partitioned table when incremental is TRUE


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


FLUSH_DATABASE_MONITORING_INFO Procedure

This procedure flushes in-memory monitoring information for all tables in the dictionary. Corresponding entries in the *_TAB_MODIFICATIONS, *_TAB_STATISTICS and *_IND_STATISTICS views are updated immediately, without waiting for the Oracle database to flush them periodically. This procedure is useful when you need up-to-date information in those views. Because the GATHER_*_STATS procedures internally flush monitoring information, it is not necessary to run this procedure before gathering the statistics.

Syntax

DBMS_STATS.FLUSH_DATABASE_MONITORING_INFO; 

Exceptions

ORA-20000: Insufficient privileges

Usage Notes

The ANALYZE_ANY system privilege is required to run this procedure.


GATHER_DATABASE_STATS Procedures

This procedure gathers statistics for all objects in the database.

Syntax

DBMS_STATS.GATHER_DATABASE_STATS (
   estimate_percent NUMBER   DEFAULT to_estimate_percent_type 
                                                (get_param('ESTIMATE_PERCENT')),
   block_sample     BOOLEAN  DEFAULT FALSE,
   method_opt       VARCHAR2 DEFAULT get_param('METHOD_OPT'),
   degree           NUMBER   DEFAULT to_degree_type(get_param('DEGREE')),
   granularity      VARCHAR2 DEFAULT GET_PARAM('GRANULARITY'), 
   cascade          BOOLEAN  DEFAULT to_cascade_type(get_param('CASCADE')),
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   options          VARCHAR2 DEFAULT 'GATHER',
   objlist          OUT      ObjectTab,
   statown          VARCHAR2 DEFAULT NULL,
   gather_sys       BOOLEAN  DEFAULT TRUE,
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   obj_filter_list ObjectTab DEFAULT NULL);

DBMS_STATS.GATHER_DATABASE_STATS (
   estimate_percent NUMBER   DEFAULT to_estimate_percent_type 
                                                (get_param('ESTIMATE_PERCENT')), 
   block_sample     BOOLEAN  DEFAULT FALSE,
   method_opt       VARCHAR2 DEFAULT get_param('METHOD_OPT'),
   degree           NUMBER   DEFAULT to_degree_type(get_param('DEGREE')),
   granularity      VARCHAR2 DEFAULT GET_PARAM('GRANULARITY'), 
   cascade          BOOLEAN  DEFAULT to_cascade_type(get_param('CASCADE')),
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   options          VARCHAR2 DEFAULT 'GATHER',
   statown          VARCHAR2 DEFAULT NULL,
   gather_sys       BOOLEAN  DEFAULT TRUE,
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   obj_filter_list ObjectTab DEFAULT NULL);

Parameters

Table 140-39 GATHER_DATABASE_STATS Procedure Parameters

Parameter Description

estimate_percent

Percentage of rows to estimate (NULL means compute): The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

block_sample

Whether or not to use random block sampling instead of random row sampling. Random block sampling is more efficient, but if the data is not randomly distributed on disk, then the sample values may be somewhat correlated. Only pertinent when doing an estimate statistics.

method_opt

Accepts:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms.
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.

The default is FOR ALL COLUMNS SIZE AUTO.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

degree

Degree of parallelism. The default for degree is NULL. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure. NULL means use the table default value specified by the DEGREE clause in the CREATE TABLE or ALTER TABLE statement. Use the constant DBMS_STATS.DEFAULT_DEGREE to specify the default value based on the initialization parameters. The AUTO_DEGREE value determines the degree of parallelism automatically. This is either 1 (serial execution) or DEFAULT_DEGREE (the system default value based on number of CPUs and initialization parameters) according to size of the object.

granularity

Granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - Gathers subpartition-level statistics

cascade

Gather statistics on the indexes as well. Using this option is equivalent to running the GATHER_INDEX_STATS Procedure on each of the indexes in the database in addition to gathering table and column statistics. Use the constant DBMS_STATS.AUTO_CASCADE to have Oracle determine whether index statistics to be collected or not. This is the default. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

stattab

User statistics table identifier describing where to save the current statistics.

The statistics table is assumed to reside in the same schema as the object being analyzed, so there must be one such table in each schema to use this option.

statid

Identifier (optional) to associate with these statistics within stattab.

options

Further specification of which objects to gather statistics for:

GATHER: Gathers statistics on all objects in the schema.

GATHER AUTO: Gathers all necessary statistics automatically. Oracle implicitly determines which objects need new statistics, and determines how to gather those statistics. When GATHER AUTO is specified, the only additional valid parameters are stattab, statid, objlist and statown; all other parameter settings are ignored. Returns a list of processed objects.

GATHER STALE: Gathers statistics on stale objects as determined by looking at the *_tab_modifications views. Also, return a list of objects found to be stale.

GATHER EMPTY: Gathers statistics on objects which currently have no statistics. Return a list of objects found to have no statistics.

LIST AUTO: Returns a list of objects to be processed with GATHER AUTO

LIST STALE: Returns a list of stale objects as determined by looking at the *_tab_modifications views

LIST EMPTY: Returns a list of objects which currently have no statistics

objlist

List of objects found to be stale or empty

statown

Schema containing stattab (if different from current schema)

gather_sys

Gathers statistics on the objects owned by the 'SYS' user

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

obj_filter_list

A list of object filters. When provided, GATHER_DATABASE_STATS will gather statistics only on objects which satisfy at least one object filter in the list as needed. In a single object filter, we can specify the constraints on the object attributes. The attribute values specified in the object filter are case- insensitive unless double-quoted. Wildcard is allowed in the attribute values. Suppose non-NULL values s1, s2, ... are specified for attributes a1, a2, ... in one object filter. An object o is said to satisfy this object filter if (o.a1 like s1) and (o.a2 like s2) and ... is true. See Applying an Object Filter List.


Usage Notes

Statistics for external tables are not collected by this procedure.

Exceptions

ORA-20000: Insufficient privileges

ORA-20001: Bad input value


GATHER_DICTIONARY_STATS Procedure

This procedure gathers statistics for dictionary schemas 'SYS', 'SYSTEM' and schemas of RDBMS components.

Syntax

DBMS_STATS.GATHER_DICTIONARY_STATS (
   comp_id          VARCHAR2 DEFAULT NULL, 
   estimate_percent NUMBER   DEFAULT to_estimate_percent_type 
                                                (get_param('ESTIMATE_PERCENT')),
   block_sample     BOOLEAN  DEFAULT FALSE,
   method_opt       VARCHAR2 DEFAULT get_param('METHOD_OPT'),
   degree           NUMBER   DEFAULT to_degree_type(get_param('DEGREE')),
   granularity      VARCHAR2 DEFAULT GET_PARAM('GRANULARITY'),
   cascade          BOOLEAN  DEFAULT to_cascade_type(get_param('CASCADE')),
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   options          VARCHAR2 DEFAULT 'GATHER AUTO', 
   objlist    OUT   ObjectTab,
   statown          VARCHAR2 DEFAULT NULL,
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   obj_filter_list ObjectTab DEFAULT NULL);

DBMS_STATS.GATHER_DICTIONARY_STATS (
   comp_id           VARCHAR2 DEFAULT NULL,
   estimate_percent  NUMBER DEFAULT 
                          to_estimate_percent_type(GET_PARAM('ESTIMATE_PERCENT')),
   block_sample      BOOLEAN DEFAULT FALSE,
   method_opt        VARCHAR2 DEFAULT GET_PARAM('METHOD_OPT'),
   degree            NUMBER DEFAULT to_degree_type(GET_PARAM('DEGREE')),
   granularity       VARCHAR2 DEFAULT GET_PARAM('GRANULARITY'),
   cascade           BOOLEAN DEFAULT to_cascade_type(GET_PARAM('CASCADE')),
   stattab           VARCHAR2 DEFAULT NULL, 
   statid            VARCHAR2 DEFAULT NULL,
   options           VARCHAR2 DEFAULT 'GATHER AUTO', 
   statown           VARCHAR2 DEFAULT NULL,
   no_invalidate     BOOLEAN DEFAULT
                               to_no_invalidate_type(get_param('NO_INVALIDATE')),
   obj_filter_list   ObjectTab DEFAULT NULL);

Parameters

Table 140-40 GATHER_DICTIONARY_STATS Procedure Parameters

Parameter Description

comp_id

Component id of the schema to analyze (NULL will result in analyzing schemas of all RDBMS components).Please refer to comp_id column of DBA_REGISTRY view. The procedure always gather statistics on 'SYS' and 'SYSTEM' schemas regardless of this argument.

estimate_percent

Percentage of rows to estimate (NULL means compute). The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

block_sample

Determines whether or not to use random block sampling instead of random row sampling. Random block sampling is more efficient, but if the data is not randomly distributed on disk then the sample values may be somewhat correlated. Only pertinent when performing estimate statistics.

method_opt

Accepts:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms.
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.

The default is FOR ALL COLUMNS SIZE AUTO.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

degree

Degree of parallelism. The default for degree is NULL. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure. NULL means use of table default value that was specified by the DEGREE clause in the CREATE or ALTER INDEX statement. Use the constant DBMS_STATS.DEFAULT_DEGREE for the default value based on the initialization parameters. The AUTO_DEGREE value determines the degree of parallelism automatically. This is either 1 (serial execution) or DEFAULT_DEGREE (the system default value based on number of CPUs and initialization parameters) according to size of the object.

granularity

Granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - gathers subpartition-level statistics

cascade

Gathers statistics on indexes also.Index statistics gathering will not be parallelized. Using this option is equivalent to running the GATHER_INDEX_STATS Procedure on each of the indexes in the schema in addition to gathering table and column statistics. Use the constant DBMS_STATS.AUTO_CASCADE to have Oracle determine whether index statistics to be collected or not. This is the default.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

stattab

User statistics table identifier describing where to save the current statistics

statid

The (optional) identifier to associate with these statistics within stattab

options

Further specification of objects for which to gather statistics:

  • 'GATHER' - Gathers statistics on all objects in the schema

  • 'GATHER AUTO' - Gathers all necessary statistics automatically. Oracle implicitly determines which objects need new statistics and determines how to gather those statistics. When 'GATHER AUTO' is specified, the only additional valid parameters are comp_id, stattab, statid and statown; all other parameter settings will be ignored. Also, returns a list of objects processed.

  • 'GATHER STALE' - Gathers statistics on stale objects as determined by looking at the *_tab_modifications views. Also, returns a list of objects found to be stale.

  • 'GATHER EMPTY' - Gathers statistics on objects which currently have no statistics. Also, returns a list of objects found to have no statistics.

  • 'LIST AUTO' - Returns list of objects to be processed with 'GATHER AUTO'

  • 'LIST STALE' - Returns list of stale objects as determined by looking at the *_tab_modifications views

  • 'LIST EMPTY' - Returns list of objects which currently have no statistics

objlist

The list of objects found to be stale or empty

statown

Schema containing stattab (if different from current schema)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

obj_filter_list

A list of object filters. When provided, this will gather statistics only on objects which satisfy at least one object filter in the list as needed. In a single object filter, we can specify the constraints on the object attributes. The attribute values specified in the object filter are case- insensitive unless double-quoted. Wildcard is allowed in the attribute values. Suppose non-NULL values s1, s2, ... are specified for attributes a1, a2, ... in one object filter. An object o is said to satisfy this object filter if (o.a1 like s1) and (o.a2 like s2) and ... is true. See Applying an Object Filter List.


Usage Notes

You must have the SYSDBA or both ANALYZE ANY DICTIONARY and ANALYZE ANY system privilege to execute this procedure.

Exceptions

ORA-20000: Index does not exist or insufficient privileges

ORA-20001: Bad input value

ORA-20002: Bad user statistics table, may need to upgrade it


GATHER_FIXED_OBJECTS_STATS Procedure

This procedure gathers statistics for all fixed objects (dynamic performance tables).

Syntax

DBMS_STATS.GATHER_FIXED_OBJECTS_STATS (
   stattab        VARCHAR2 DEFAULT NULL,
   statid         VARCHAR2 DEFAULT NULL,
   statown        VARCHAR2 DEFAULT NULL, 
   no_invalidate  BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE'))); 

Parameters

Table 140-41 GATHER_FIXED_OBJECTS_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing where to save the current statistics

statid

Identifier to associate with these statistics within stattab (optional)

statown

Schema containing stattab (if different from current schema)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.


Usage Notes

You must have the SYSDBA or ANALYZE ANY DICTIONARY system privilege to execute this procedure.

Exceptions

ORA-20000: Insufficient privileges

ORA-20001: Bad input value

ORA-20002: Bad user statistics table, may need to upgrade it


GATHER_INDEX_STATS Procedure

This procedure gathers index statistics. It attempts to parallelize as much of the work as possible. Restrictions are described in the individual parameters. This operation will not parallelize with certain types of indexes, including cluster indexes, domain indexes, and bitmap join indexes. The granularity and no_invalidate arguments are not relevant to these types of indexes.

Syntax

DBMS_STATS.GATHER_INDEX_STATS (
   ownname          VARCHAR2, 
   indname          VARCHAR2, 
   partname         VARCHAR2 DEFAULT NULL,
   estimate_percent NUMBER   DEFAULT to_estimate_percent_type 
                                                (GET_PARAM('ESTIMATE_PERCENT')),
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   statown          VARCHAR2 DEFAULT NULL,
   degree           NUMBER   DEFAULT to_degree_type(get_param('DEGREE')),
   granularity      VARCHAR2 DEFAULT GET_PARAM('GRANULARITY'),
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type 
                                               (GET_PARAM('NO_INVALIDATE')),
   force            BOOLEAN DEFAULT FALSE);

Parameters

Table 140-42 GATHER_INDEX_STATS Procedure Parameters

Parameter Description

ownname

Schema of index to analyze

indname

Name of index

partname

Name of partition

estimate_percent

Percentage of rows to estimate (NULL means compute). The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

stattab

User statistics table identifier describing where to save the current statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)

degree

Degree of parallelism. The default for degree is NULL. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure. NULL means use of table default value that was specified by the DEGREE clause in the CREATE/ALTER INDEX statement. Use the constant DBMS_STATS.DEFAULT_DEGREE for the default value based on the initialization parameters. The AUTO_DEGREE value determines the degree of parallelism automatically. This is either 1 (serial execution) or DEFAULT_DEGREE (the system default value based on number of CPUs and initialization parameters) according to size of the object.

granularity

Granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - Gathers subpartition-level statistics.

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

Gather statistics on object even if it is locked


Exceptions

ORA-20000: Index does not exist or insufficient privileges

ORA-20001: Bad input value


GATHER_SCHEMA_STATS Procedures

This procedure gathers statistics for all objects in a schema.

Syntax

DBMS_STATS.GATHER_SCHEMA_STATS ( 
   ownname          VARCHAR2, 
   estimate_percent NUMBER   DEFAULT to_estimate_percent_type 
                                                (get_param('ESTIMATE_PERCENT')), 
   block_sample     BOOLEAN  DEFAULT FALSE, 
   method_opt       VARCHAR2 DEFAULT get_param('METHOD_OPT'),
   degree           NUMBER   DEFAULT to_degree_type(get_param('DEGREE')), 
   granularity      VARCHAR2 DEFAULT GET_PARAM('GRANULARITY'), 
   cascade          BOOLEAN  DEFAULT to_cascade_type(get_param('CASCADE')), 
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL, 
   options          VARCHAR2 DEFAULT 'GATHER', 
   objlist          OUT      ObjectTab,
   statown          VARCHAR2 DEFAULT NULL, 
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
  force             BOOLEAN DEFAULT FALSE,
  obj_filter_list  ObjectTab DEFAULT NULL);
   
DBMS_STATS.GATHER_SCHEMA_STATS ( 
   ownname          VARCHAR2, 
   estimate_percent NUMBER   DEFAULT to_estimate_percent_type 
                                                (get_param('ESTIMATE_PERCENT')), 
   block_sample     BOOLEAN  DEFAULT FALSE, 
   method_opt       VARCHAR2 DEFAULT get_param('METHOD_OPT'), 
   degree           NUMBER   DEFAULT to_degree_type(get_param('DEGREE')), 
   granularity      VARCHAR2 DEFAULT GET_PARAM('GRANULARITY'), 
   cascade          BOOLEAN  DEFAULT to_cascade_type(get_param('CASCADE')), 
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL, 
   options          VARCHAR2 DEFAULT 'GATHER', 
   statown          VARCHAR2 DEFAULT NULL, 
   no_invalidate    BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE'), 
   force            BOOLEAN DEFAULT FALSE,
   obj_filter_list  ObjectTab DEFAULT NULL);

Parameters

Table 140-43 GATHER_SCHEMA_STATS Procedure Parameters

Parameter Description

ownname

Schema to analyze (NULL means current schema)

estimate_percent

Percentage of rows to estimate (NULL means compute): The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

block_sample

Whether or not to use random block sampling instead of random row sampling. Random block sampling is more efficient, but if the data is not randomly distributed on disk, then the sample values may be somewhat correlated. Only pertinent when doing an estimate statistics.

method_opt

Accepts:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.

The default is FOR ALL COLUMNS SIZE AUTO.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

degree

Degree of parallelism. The default for degree is NULL. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure. NULL means use the table default value specified by the DEGREE clause in the CREATE TABLE or ALTER TABLE statement. Use the constant DBMS_STATS.DEFAULT_DEGREE to specify the default value based on the initialization parameters.The AUTO_DEGREE value determines the degree of parallelism automatically. This is either 1 (serial execution) or DEFAULT_DEGREE (the system default value based on number of CPUs and initialization parameters) according to size of the object.

granularity

Granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - Gathers subpartition-level statistics.

cascade

Gather statistics on the indexes as well. Using this option is equivalent to running the GATHER_INDEX_STATS Procedure on each of the indexes in the schema in addition to gathering table and column statistics. Use the constant DBMS_STATS.AUTO_CASCADE to have Oracle determine whether index statistics to be collected or not. This is the default. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

stattab

User statistics table identifier describing where to save the current statistics

statid

Identifier (optional) to associate with these statistics within stattab

options

Further specification of which objects to gather statistics for:

GATHER: Gathers statistics on all objects in the schema.

GATHER AUTO: Gathers all necessary statistics automatically. Oracle implicitly determines which objects need new statistics, and determines how to gather those statistics. When GATHER AUTO is specified, the only additional valid parameters are ownname, stattab, statid, objlist and statown; all other parameter settings are ignored. Returns a list of processed objects.

GATHER STALE: Gathers statistics on stale objects as determined by looking at the *_tab_modifications views. Also, return a list of objects found to be stale.

GATHER EMPTY: Gathers statistics on objects which currently have no statistics. also, return a list of objects found to have no statistics.

LIST AUTO: Returns a list of objects to be processed with GATHER AUTO.

LIST STALE: Returns list of stale objects as determined by looking at the *_tab_modifications views.

LIST EMPTY: Returns list of objects which currently have no statistics.

objlist

List of objects found to be stale or empty

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

Gather statistics on objects even if they are locked

obj_filter_list

A list of object filters. When provided, GATHER_SCHEMA_STATS will gather statistics only on objects which satisfy at least one object filter in the list as needed. In a single object filter, we can specify the constraints on the object attributes. The attribute values specified in the object filter are case- insensitive unless double-quoted. Wildcard is allowed in the attribute values. Suppose non-NULL values s1, s2, ... are specified for attributes a1, a2, ... in one object filter. An object o is said to satisfy this object filter if (o.a1 like s1) and (o.a2 like s2) and ... is true. See Applying an Object Filter List.


Usage Notes

When you use a specific value for the sampling percentage, DBMS_STATS honors it except for when:

Statistics for external tables are not collected by this procedure.

Exceptions

ORA-20000: Schema does not exist or insufficient privileges

ORA-20001: Bad input value

Examples

Applying an Object Filter List

The following example specifies that any table with a "T" prefix in the SAMPLE schema and any table in the SYS schema, if stale, will have statistics gathered upon it.

DECLARE
      filter_lst  DBMS_STATS.OBJECTTAB := DBMS_STATS.OBJECTTAB();
    BEGIN
      filter_lst.extend(2);
      filter_lst(1).ownname := 'SAMPLE';
      filter_lst(1).objname := 'T%';
      filter_lst(2).ownname := 'SYS';
      DBMS_STATS.GATHER_SCHEMA_STATS(NULL, obj_filter_list => filter_lst,
                                     options => 'gather_stale');
    END; 

GATHER_SYSTEM_STATS Procedure

This procedure gathers system statistics.

Syntax

DBMS_STATS.GATHER_SYSTEM_STATS (
   gathering_mode   VARCHAR2 DEFAULT 'NOWORKLOAD',
   interval         INTEGER  DEFAULT NULL,
   stattab          VARCHAR2 DEFAULT NULL,
   statid           VARCHAR2 DEFAULT NULL,
   statown          VARCHAR2 DEFAULT NULL);

Parameters

Table 140-44 GATHER_SYSTEM_STATS Procedure Parameters

Parameter Description

gathering_mode

Mode values are:

NOWORKLOAD: Will capture characteristics of the I/O system. Gathering may take a few minutes and depends on the size of the database. During this period Oracle will estimate the average read seek time and transfer speed for the I/O system. This mode is suitable for the all workloads. Oracle recommends to run GATHER_SYSTEM_STATS ('noworkload') after creation of the database and tablespaces. To fine tune system statistics for the workload use 'START' and 'STOP' or 'INTERVAL' options. If you gather both 'NOWORKLOAD' and workload specific (statistics collected using 'INTERVAL' or 'START' and 'STOP' ), the workload statistics will be used by optimizer. Collected components: cpuspeednw, ioseektim, iotfrspeed.

INTERVAL: Captures system activity during a specified interval. This works in combination with the interval parameter. You should provide an interval value in minutes, after which system statistics are created or updated in the dictionary or stattab. You can use GATHER_SYSTEM_STATS (gathering_mode=>'STOP') to stop gathering earlier than scheduled. Collected components: maxthr, slavethr, cpuspeed, sreadtim, mreadtim, mbrc.

START | STOP: Captures system activity during specified start and stop times and refreshes the dictionary or stattab with statistics for the elapsed period. Interval value is ignored. Collected components: maxthr, slavethr, cpuspeed, sreadtim, mreadtim, mbrc.

interval

Time, in minutes, to gather statistics. This parameter applies only when gathering_mode='INTERVAL'

stattab

Identifier of the user statistics table where the statistics will be saved

statid

Optional identifier associated with the statistics saved in the stattab

statown

Schema containing stattab (if different from current schema)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid input value

ORA-20002: Bad user statistics table; may need to be upgraded

ORA-20003: Unable to gather system statistics

ORA-20004: Error in the INTERVAL mode: system parameter job_queue_processes must be >0


GATHER_TABLE_STATS Procedure

This procedure gathers table and column (and index) statistics. It attempts to parallelize as much of the work as possible, but there are some restrictions as described in the individual parameters.

Syntax

DBMS_STATS.GATHER_TABLE_STATS (
   ownname          VARCHAR2, 
   tabname          VARCHAR2, 
   partname         VARCHAR2 DEFAULT NULL,
   estimate_percent NUMBER   DEFAULT to_estimate_percent_type 
                                                (get_param('ESTIMATE_PERCENT')), 
   block_sample     BOOLEAN  DEFAULT FALSE,
   method_opt       VARCHAR2 DEFAULT get_param('METHOD_OPT'),
   degree           NUMBER   DEFAULT to_degree_type(get_param('DEGREE')),
   granularity      VARCHAR2 DEFAULT GET_PARAM('GRANULARITY'), 
   cascade          BOOLEAN  DEFAULT to_cascade_type(get_param('CASCADE')),
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   statown          VARCHAR2 DEFAULT NULL,
   no_invalidate    BOOLEAN  DEFAULT  to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   stattype         VARCHAR2 DEFAULT 'DATA',
   force            BOOLEAN  DEFAULT FALSE);

Parameters

Table 140-45 GATHER_TABLE_STATS Procedure Parameters

Parameter Description

ownname

Schema of table to analyze

tabname

Name of table

partname

Name of partition

estimate_percent

Percentage of rows to estimate (NULL means compute) The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

block_sample

Whether or not to use random block sampling instead of random row sampling. Random block sampling is more efficient, but if the data is not randomly distributed on disk, then the sample values may be somewhat correlated. Only pertinent when doing an estimate statistics.

method_opt

Accepts either of the following options, or both in combination:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.
- column_name : Name of a column
- extension : can be either a column group in the format of (column_name, Colume_name [, ...]) or an expression

The default is FOR ALL COLUMNS SIZE AUTO. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

degree

Degree of parallelism. The default for degree is NULL. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure. NULL means use the table default value specified by the DEGREE clause in the CREATE TABLE or ALTER TABLE statement. Use the constant DBMS_STATS.DEFAULT_DEGREE to specify the default value based on the initialization parameters. The AUTO_DEGREE value determines the degree of parallelism automatically. This is either 1 (serial execution) or DEFAULT_DEGREE (the system default value based on number of CPUs and initialization parameters) according to size of the object.

granularity

Granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'APPROX_GLOBAL AND PARTITION' - similar to 'GLOBAL AND PARTITION' but in this case the global statistics are aggregated from partition level statistics. This option will aggregate all statistics except the number of distinct values for columns and number of distinct keys of indexes. The existing histograms of the columns at the table level are also aggregated.The aggregation will use only partitions with statistics, so to get accurate global statistics, users should make sure to have statistics for all partitions. Global statistics are gathered if partname is NULL or if the aggregation cannot be performed (for example, if statistics for one of the partitions is missing).

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - Gathers subpartition-level statistics.

cascade

Gathers statistics on the indexes for this table. Using this option is equivalent to running the GATHER_INDEX_STATS Procedure on each of the table's indexes. Use the constant DBMS_STATS.AUTO_CASCADE to have Oracle determine whether index statistics are to be collected or not. This is the default. The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

stattab

User statistics table identifier describing where to save the current statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

stattype

Statistics type. The only value allowed is DATA.

force

Gather statistics of table even if it is locked


Usage Notes

Index statistics collection can be parellelized except for cluster, domain and join indexes.

Exceptions

ORA-20000: Table does not exist or insufficient privileges

ORA-20001: Bad input value

Examples

An extension can be either a column group (see Example 1) or an expression (see Example 2).

Example 1

DBMS_STATS.GATHER_TABLE_STATS(
    'SH', 'SALES', method_opt => 'FOR COLUMNS (empno, deptno)'); 

Example 2

DBMS_STATS.GATHER_TABLE_STATS(
    'SH', 'SALES', method_opt => 'FOR COLUMNS (sal+comm)');

GENERATE_STATS Procedure

This procedure generates object statistics from previously collected statistics of related objects. The currently supported objects are b-tree and bitmap indexes.

Syntax

DBMS_STATS.GENERATE_STATS (
   ownname    VARCHAR2, 
   objname    VARCHAR2,
   organized  NUMBER DEFAULT 7,
   force      BOOLEAN default FALSE);

Parameters

Table 140-46 GENERATE_STATS Procedure Parameters

Parameter Description

ownname

Schema of object

objname

Name of object

organized

Amount of ordering associated between the index and its underlying table. A heavily organized index would have consecutive index keys referring to consecutive rows on disk for the table (the same block). A heavily disorganized index would have consecutive keys referencing different table blocks on disk.

This parameter is only used for b-tree indexes. The number can be in the range of 0-10, with 0 representing a completely organized index and 10 a completely disorganized one.

force

If TRUE, generates statistics for the target object even if it is locked


Usage Notes

For fully populated schemas, the gather procedures should be used instead when more accurate statistics are desired.

Exceptions

ORA-20000: Unsupported object type of object does not exist

ORA-20001: Invalid option or invalid statistics


GET_COLUMN_STATS Procedures

These procedures gets all column-related information. In the form of this procedure that deals with user-defined statistics, the statistics type returned is the type stored, in addition to the user-defined statistics.

Syntax

DBMS_STATS.GET_COLUMN_STATS (
   ownname     VARCHAR2, 
   tabname     VARCHAR2, 
   colname     VARCHAR2, 
   partname    VARCHAR2 DEFAULT NULL,
   stattab     VARCHAR2 DEFAULT NULL, 
   statid      VARCHAR2 DEFAULT NULL,
   distcnt OUT NUMBER, 
   density OUT NUMBER,
   nullcnt OUT NUMBER, 
   srec    OUT StatRec,
   avgclen OUT NUMBER,
   statown     VARCHAR2 DEFAULT NULL);

Use the following for user-defined statistics:

DBMS_STATS.GET_COLUMN_STATS (
   ownname          VARCHAR2, 
   tabname          VARCHAR2, 
   colname          VARCHAR2, 
   partname         VARCHAR2 DEFAULT NULL,
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   ext_stats   OUT  RAW,
   stattypown  OUT  VARCHAR2 DEFAULT NULL, 
   stattypname OUT  VARCHAR2 DEFAULT NULL, 
   statown          VARCHAR2 DEFAULT NULL);

Parameters

Table 140-47 GET_COLUMN_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table to which this column belongs

colname

Name of the column or extension

partname

Name of the table partition from which to get the statistics. If the table is partitioned and if partname is NULL, statistics are retrieved from the global table level.

stattab

User statistics table identifier describing from where to retrieve the statistics. If stattab is NULL, statistics are retrieved directly from the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

ext_stats

The user-defined statistics

stattypown

Schema of the statistics type

stattypname

Name of the statistics type

distcnt

Number of distinct values

density

Column density

nullcnt

Number of NULLs

srec

Structure holding internal representation of column minimum, maximum, and histogram values

avgclen

Average length of the column (in bytes)

statown

Schema containing stattab (if different than ownname)


Exceptions

ORA-20000: Object does not exist or insufficient privileges or no statistics have been stored for requested object


GET_INDEX_STATS Procedures

These procedures get all index-related information. In the form of this procedure that deals with user-defined statistics, the statistics type returned is the type stored, in addition to the user-defined statistics.

Syntax

DBMS_STATS.GET_INDEX_STATS (
   ownname        VARCHAR2, 
   indname        VARCHAR2,
   partname       VARCHAR2 DEFAULT NULL,
   stattab        VARCHAR2 DEFAULT NULL, 
   statid         VARCHAR2 DEFAULT NULL,
   numrows    OUT NUMBER, 
   numlblks   OUT NUMBER,
   numdist    OUT NUMBER, 
   avglblk    OUT NUMBER,
   avgdblk    OUT NUMBER, 
   clstfct    OUT NUMBER,
   indlevel   OUT NUMBER,
   statown        VARCHAR2 DEFAULT NULL,
   cachedblk  OUT NUMBER,
   cachehit   OUT NUMBER);

DBMS_STATS.GET_INDEX_STATS (
   ownname        VARCHAR2, 
   indname        VARCHAR2,
   partname       VARCHAR2 DEFAULT NULL,
   stattab        VARCHAR2 DEFAULT NULL, 
   statid         VARCHAR2 DEFAULT NULL,
   numrows    OUT NUMBER, 
   numlblks   OUT NUMBER,
   numdist    OUT NUMBER, 
   avglblk    OUT NUMBER,
   avgdblk    OUT NUMBER, 
   clstfct    OUT NUMBER,
   indlevel   OUT NUMBER,
   statown        VARCHAR2 DEFAULT NULL,
   guessq     OUT NUMBER,
   cachedblk  OUT NUMBER,
   cachehit   OUT NUMBER);

Use the following for user-defined statistics:

DBMS_STATS.GET_INDEX_STATS (
   ownname          VARCHAR2, 
   indname          VARCHAR2,
   partname         VARCHAR2 DEFAULT NULL,
   stattab          VARCHAR2 DEFAULT NULL, 
   statid           VARCHAR2 DEFAULT NULL,
   ext_stats   OUT  RAW,
   stattypown  OUT  VARCHAR2 DEFAULT NULL, 
   stattypname OUT  VARCHAR2 DEFAULT NULL, 
   statown          VARCHAR2 DEFAULT NULL,
   cachedblk        OUT NUMBER,
   cachehit         OUT NUMBER);

Parameters

Table 140-48 GET_INDEX_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

indname

Name of the index

partname

Name of the index partition for which to get the statistics. If the index is partitioned and if partname is NULL, then the statistics are retrieved for the global index level.

stattab

User statistics table identifier describing from where to retrieve the statistics. If stattab is NULL, then the statistics are retrieved directly from the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

ext_stats

User-defined statistics

stattypown

Schema of the statistics type

stattypname

Name of the statistics type

numrows

Number of rows in the index (partition)

numlblks

Number of leaf blocks in the index (partition)

numdist

Number of distinct keys in the index (partition)

avglblk

Average integral number of leaf blocks in which each distinct key appears for this index (partition)

avgdblk

Average integral number of data blocks in the table pointed to by a distinct key for this index (partition)

clstfct

Clustering factor for the index (partition)

indlevel

Height of the index (partition)

statown

Schema containing stattab (if different than ownname)

guessq

Guess quality for the index (partition)

cachedblk

The average number of blocks in the buffer cache for the segment (index/table/index partition/table partition)

cachehit

The average cache hit ratio for the segment (index/table/index partition/table partition)


Usage Notes

Exceptions

ORA-20000: Object does not exist or insufficient privileges or no statistics have been stored for requested object


GET_PARAM Function

Note:

This subprogram has been replaced by improved technology and is maintained only for purposes of backward compatibility. In this case, use the GET_PREFS Function.

See also Deprecated Subprograms.

This function returns the default value of parameters of DBMS_STATS procedures.

Syntax

DBMS_STATS.GET_PARAM (
   pname     IN   VARCHAR2)
 RETURN VARCHAR2;

Parameters

Table 140-49 GET_PARAM Function Parameters

Parameter Description

pname

Parameter name


Exceptions

ORA-20001: Invalid input values


GET_PREFS Function

This function returns the default value of the specified preference.

Syntax

DBMS_STATS.GET_PREFS (
   pname     IN   VARCHAR2,
   ownname   IN   VARCHAR2 DEFAULT NULL,   tabname   IN   VARCHAR2 DEFAULT NULL)
 RETURN VARCHAR2;

Parameters

Table 140-50 GET_PREFS Function Parameters

Parameter Description

pname

Preference name. The default value for following preferences can be retrieved:

  • AUTOSTATS_TARGET

  • CASCADE

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • PUBLISH

  • INCREMENTAL

  • STALE_PERCENT

 

AUTOSTATS_TARGET - This preference is applicable only for auto statistics collection. The value of this parameter controls the objects considered for statistics collection. It takes the following values:

  • 'ALL' - Statistics collected for all objects in system

  • 'ORACLE' - Statistics collected for all Oracle owned objects

  • 'AUTO' - Oracle decides on which objects to collect statistics

.

CASCADE - Determines whether or not index statistics are collected as part of gathering table statistics.

.

DEGREE - Determines degree of parallelism used for gathering statistics.

.

ESTIMATE_PERCENT - Determines the percentage of rows to estimate. The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.

.

METHOD_OPT - Controls column statistics collection and histogram creation. It accepts either of the following options, or both in combination:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms.
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.
- column_name : name of a column
- extension : can be either a column group in the format of (column_name, colume_name [, ...]) or an expression

The default is FOR ALL COLUMNS SIZE AUTO.The default value can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

.

NO_INVALIDATE - The value controls the invalidation of dependent cursors of the tables for which statistics are being gathered. Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE to have Oracle decide when to invalidate dependent cursors. This is the default.

.

GRANULARITY - Determines granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - Gathers subpartition-level statistics.

.

PUBLISH - Determines whether or not newly gathered statistics will be published once the gather job has completed. Prior to Oracle Database 11g, Release 1 (11.1), once a statistic gathering job completed the new statistics were automatically published into the dictionary tables. The user now has the ability to gather statistics but not publish them immediately. This allows the DBA to test the new statistics before publishing them.

.

INCREMENTAL - Determines whether or not the global statistics of a partitioned table will be maintained without doing a full table scan. With partitioned tables it is very common to load new data into a new partition. As new partitions are added and data loaded, the global table statistics need to be kept up to date. Oracle will update the global table statistics by scanning only the partitions that have been changed instead of the entire table if the following conditions hold:

  • INCREMENTAL value for the partitioned table is set to TRUE

  • PUBLISH value for the partitioned table is set to TRUE;

  • User specifies AUTO_SAMPLE_SIZE for ESTIMATE_PERCENT and AUTO for GRANULARITY when gathering statistics on the table

If the INCREMENTAL value for the partitioned table was set to FALSE (default value), a full table scan is used to maintain the global statistics which is a much more resource intensive and time-consuming operation for large tables.

.

STALE_PERCENT - This value determines the percentage of rows in a table that have to change before the statistics on that table are deemed stale and should be regathered. The default value is 10%.

ownname

Owner name

tabname

Table name


Exceptions

ORA-20001: Invalid input values

Usage Notes

If the ownname and tabname are provided and a preference has been entered for the table, the function returns the preference as specified for the table. In all other cases it returns the global preference if it has been specified, otherwise the default value is returned.


GET_STATS_HISTORY_AVAILABILITY Function

This function returns oldest timestamp where statistics history is available.Users cannot restore statistics to a timestamp older than this one.

Syntax

DBMS_STATS.GET_STATS_HISTORY_AVAILABILITY
 RETURN TIMESTAMP WITH TIMEZONE;

GET_STATS_HISTORY_RETENTION Function

This function returns the current retention value.

Syntax

DBMS_STATS.GET_STATS_HISTORY_RETENTION
 RETURN NUMBER;

GET_SYSTEM_STATS Procedure

This procedure gets system statistics from stattab, or from the dictionary if stattab is NULL.

Syntax

DBMS_STATS.GET_SYSTEM_STATS (
   status    OUT  VARCHAR2,
   dstart    OUT  DATE,
   dstop     OUT  DATE,
   pname          VARCHAR2,
   pvalue    OUT  NUMBER,
   stattab   IN   VARCHAR2 DEFAULT NULL, 
   statid    IN   VARCHAR2 DEFAULT NULL,
   statown   IN   VARCHAR2 DEFAULT NULL);

Parameters

Table 140-51 GET_SYSTEM_STATS Procedure Parameters

Parameter Description

status

Output is one of the following:

  • COMPLETED:

  • AUTOGATHERING:

  • MANUALGATHERING:

  • BADSTATS:

dstart

Date when statistics gathering started.

If status = MANUALGATHERING, the start date is returned.

dstop

Date when statistics gathering stopped.

  • If status = COMPLETE, the finish date is returned.

  • If status = AUTOGATHERING, the future finish date is returned.

  • If status = BADSTATS, the must-finished-by date is returned.

pname

The parameter name to get, which can have one of the following values:

  • iotfrspeed - I/O transfer speed in bytes for each millisecond

  • ioseektim - seek time + latency time + operating system overhead time, in milliseconds

  • sreadtim - average time to read single block (random read), in milliseconds

  • mreadtim - average time to read an mbrc block at once (sequential read), in milliseconds

  • cpuspeed - average number of CPU cycles for each second, in millions, captured for the workload (statistics collected using 'INTERVAL' or 'START' and 'STOP' options)

  • cpuspeednw - average number of CPU cycles for each second, in millions, captured for the noworkload (statistics collected using 'NOWORKLOAD' option.

  • mbrc - average multiblock read count for sequential read, in blocks

  • maxthr - maximum I/O system throughput, in bytes/second

  • slavethr - average slave I/O throughput, in bytes/second

pvalue

Parameter value to get

stattab

Identifier of the user statistics table where the statistics will be obtained. If stattab is null, the statistics will be obtained from the dictionary.

statid

Optional identifier associated with the statistics saved in the stattab

statown

Schema containing stattab (if different from current schema)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20002: Bad user statistics table; may need to be upgraded

ORA-20003: Unable to gather system statistics

ORA-20004: Parameter does not exist


GET_TABLE_STATS Procedure

This procedure gets all table-related information.

Syntax

DBMS_STATS.GET_TABLE_STATS (
   ownname         VARCHAR2, 
   tabname         VARCHAR2, 
   partname        VARCHAR2 DEFAULT NULL,
   stattab         VARCHAR2 DEFAULT NULL,
   statid          VARCHAR2 DEFAULT NULL,
   numrows     OUT NUMBER, 
   numblks     OUT NUMBER,
   avgrlen     OUT NUMBER,
   statown         VARCHAR2 DEFAULT NULL,
   cachedblk   OUT NUMBER,
   cachehit    OUT NUMBER);

Parameters

Table 140-52 GET_TABLE_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table to which this column belongs

partname

Name of the table partition from which to get the statistics. If the table is partitioned and if partname is NULL, then the statistics are retrieved from the global table level.

stattab

User statistics table identifier describing from where to retrieve the statistics. If stattab is NULL, then the statistics are retrieved directly from the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

numrows

Number of rows in the table (partition)

numblks

Number of blocks the table (partition) occupies

avgrlen

Average row length for the table (partition)

statown

Schema containing stattab (if different than ownname)

cachedblk

The average number of blocks in the buffer cache for the segment (index/table/index partition/table partition)

cachehit

The average cache hit ratio for the segment (index/table/index partition/table partition)


Usage Notes

Exceptions

ORA-20000: Object does not exist or insufficient privileges or no statistics have been stored for requested object

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


IMPORT_COLUMN_STATS Procedure

This procedure retrieves statistics for a particular column from the user statistics table identified by stattab and stores them in the dictionary.

Syntax

DBMS_STATS.IMPORT_COLUMN_STATS (
   ownname       VARCHAR2, 
   tabname       VARCHAR2, 
   colname       VARCHAR2,
   partname      VARCHAR2 DEFAULT NULL,
   stattab       VARCHAR2, 
   statid        VARCHAR2 DEFAULT NULL,
   statown       VARCHAR2 DEFAULT NULL,
   no_invalidate BOOLEAN DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   force         BOOLEAN DEFAULT FALSE);

Parameters

Table 140-53 IMPORT_COLUMN_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table to which this column belongs

colname

Name of the column or extension

partname

Name of the table partition. If the table is partitioned and if partname is NULL, then global and partition column statistics are imported.

stattab

User statistics table identifier describing from where to retrieve the statistics

statid

Identifier to associate with these statistics within stattab (optional)

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

If set to TRUE, imports statistics even if statistics are locked


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values in the user statistics table

ORA-20005: Object statistics are locked

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


IMPORT_DATABASE_PREFS Procedure

This procedure is used to import the statistics preferences of all the tables, excluding the tables owned by Oracle. These tables can by included by passing TRUE for the add_sys parameter.

Syntax

DBMS_STATS.IMPORT_DATABASE_PREFS (
    stattab    IN  VARCHAR2,
    statid     IN  VARCHAR2 DEFAULT NULL,
    statown    IN  VARCHAR2 DEFAULT NULL
    add_sys    IN  BOOLEAN DEFAULT FALSE);

Parameters

Table 140-54 IMPORT_DATABASE_PREFS Procedure Parameters

Parameter Description

stattab

Statistics table name where to import the statistics

statid

Optional identifier to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)

add_sys

Value TRUE will include the Oracle-owned tables


Exceptions

ORA-20000: Insufficient privileges.

Usage Notes

Examples

DBMS_STATS.IMPORT_DATABASE_PREFS('STATTAB', statown=>'SH');

IMPORT_DATABASE_STATS Procedure

This procedure retrieves statistics for all objects in the database from the user statistics table(s) and stores them in the dictionary.

Syntax

DBMS_STATS.IMPORT_DATABASE_STATS (
   stattab         VARCHAR2, 
   statid          VARCHAR2 DEFAULT NULL,
   statown         VARCHAR2 DEFAULT NULL,
   no_invalidate   BOOLEAN DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   force           BOOLEAN DEFAULT FALSE,
   stat_category   VARCHAR2 DEFAULT DEFAULT_STAT_CATEGORY);

Parameters

Table 140-55 IMPORT_DATABASE_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing from where to retrieve the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different from current schema)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

Overrides statistics locked at the object (table) level:

  • TRUE - Ignores the statistics lock and imports the statistics

  • FALSE - The statistics will be imported only if they are not locked

stat_category

Specifies what statistics to import, accepting multiple values separated by a comma. Values supported:

  • 'OBJECT_STATS' - table statistics, column statistics and index statistics (Default)

  • 'SYNOPSES' - auxiliary statistics information gathered on a partitioned table when incremental is TRUE


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values in the user statistics table

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


IMPORT_DICTIONARY_STATS Procedure

This procedure retrieves statistics for all dictionary schemas ('SYS', 'SYSTEM' and RDBMS component schemas) from the user statistics table and stores them in the dictionary.

Syntax

DBMS_STATS.IMPORT_DICTIONARY_STATS (
   stattab         VARCHAR2, 
   statid          VARCHAR2 DEFAULT NULL,
   statown         VARCHAR2 DEFAULT NULL,
   no_invalidate   BOOLEAN DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   force           BOOLEAN DEFAULT FALSE,
   stat_category   VARCHAR2 DEFAULT DEFAULT_STAT_CATEGORY);

Parameters

Table 140-56 IMPORT_DICTIONARY_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing from where to retrieve the statistics

statid

The (optional) identifier to associate with these statistics within stattab

statown

Schema containing stattab (if different from current schema)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

Overrides statistics lock at the object (table) level:

  • TRUE - Ignores the statistics lock and imports the statistics.

  • FALSE - The statistics will be imported only if there is no lock.

stat_category

Specifies what statistics to import, accepting multiple values separated by a comma. Values supported:

  • 'OBJECT_STATS' - table statistics, column statistics and index statistics (Default)

  • 'SYNOPSES' - auxiliary statistics information gathered on a partitioned table when incremental is TRUE


Usage Notes

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values in the user statistics table

ORA-20002: Bad user statistics table, may need to upgrade it


IMPORT_FIXED_OBJECTS_STATS Procedure

This procedure retrieves statistics for fixed tables from the user statistics table(s) and stores them in the dictionary.

Syntax

DBMS_STATS.IMPORT_FIXED_OBJECTS_STATS (
   stattab       VARCHAR2, 
   statid        VARCHAR2 DEFAULT NULL,
   statown       VARCHAR2 DEFAULT NULL,
   no_invalidate BOOLEAN DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   force         BOOLEAN DEFAULT FALSE);

Parameters

Table 140-57 IMPORT_FIXED_OBJECTS_STATS Procedure Parameters

Parameter Description

stattab

User statistics table identifier describing from where to retrieve the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different from current schema)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

Overrides statistics lock:

  • TRUE - Ignores the statistics lock and imports the statistics

  • FALSE - The statistics will be imported only if there is no lock


Usage Notes

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values in the user statistics table

ORA-20002: Bad user statistics table, may need to upgrade it


IMPORT_INDEX_STATS Procedure

This procedure retrieves statistics for a particular index from the user statistics table identified by stattab and stores them in the dictionary.

Syntax

DBMS_STATS.IMPORT_INDEX_STATS (
   ownname       VARCHAR2, 
   indname       VARCHAR2,
   partname      VARCHAR2 DEFAULT NULL,
   stattab       VARCHAR2, 
   statid        VARCHAR2 DEFAULT NULL,
   statown       VARCHAR2 DEFAULT NULL,
   no_invalidate BOOLEAN DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   force         BOOLEAN DEFAULT FALSE);

Parameters

Table 140-58 IMPORT_INDEX_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

indname

Name of the index

partname

Name of the index partition. If the index is partitioned and if partname is NULL, then global and partition index statistics are imported.

stattab

User statistics table identifier describing from where to retrieve the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

Imports statistics even if index statistics are locked


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values in the user statistics table

ORA-20005: Object statistics are locked

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


IMPORT_SCHEMA_PREFS Procedure

This procedure is used to import the statistics preferences of all the tables owned by the specified owner name.

Syntax

DBMS_STATS.IMPORT_SCHEMA_PREFS (
    ownname    IN  VARCHAR2,    stattab    IN  VARCHAR2,    statid     IN  VARCHAR2 DEFAULT NULL,    statown    IN  VARCHAR2 DEFAULT NULL);

Parameters

Table 140-59 IMPORT_SCHEMA_PREFS Procedure Parameters

Parameter Description

ownname

Owner name

stattab

Statistics table name from where to import the statistics

statid

(Optional) Identifier to associate with these statistics within stattab

statown

Schema containing stattab (if other than ownname)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Examples

DBMS_STATS.IMPORT_SCHEMA_PREFS('SH', 'STAT');

IMPORT_SCHEMA_STATS Procedure

This procedure retrieves statistics for all objects in the schema identified by ownname from the user statistics table and stores them in the dictionary.

Syntax

DBMS_STATS.IMPORT_SCHEMA_STATS (
   ownname         VARCHAR2,
   stattab         VARCHAR2, 
   statid          VARCHAR2 DEFAULT NULL,
   statown         VARCHAR2 DEFAULT NULL,
   no_invalidate   BOOLEAN DEFAULTto_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   force           BOOLEAN DEFAULT FALSE,
   stat_category   VARCHAR2 DEFAULT DEFAULT_STAT_CATEGORY);

Parameters

Table 140-60 IMPORT_SCHEMA_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

stattab

User statistics table identifier describing from where to retrieve the statistics

statid

Identifier (optional) to associate with these statistics within stattab

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

Overrides statistics locked at the object (table) level:

  • TRUE - Ignores the statistics lock and imports the statistics.

  • FALSE - Statistics will be imported only if there is no lock.

stat_category

Specifies what statistics to import, accepting multiple values separated by a comma. Values supported:

  • 'OBJECT_STATS' - table statistics, column statistics and index statistics (Default)

  • 'SYNOPSES' - auxiliary statistics information gathered on a partitioned table when incremental is TRUE


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values in the user statistics table

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


IMPORT_SYSTEM_STATS Procedure

This procedure retrieves system statistics from the user statistics table, identified by stattab, and stores the statistics in the dictionary.

Syntax

DBMS_STATS.IMPORT_SYSTEM_STATS (
   stattab       VARCHAR2, 
   statid        VARCHAR2 DEFAULT NULL,
   statown       VARCHAR2 DEFAULT NULL);

Parameters

Table 140-61 IMPORT_SYSTEM_STATS Procedure Parameters

Parameter Description

stattab

Identifier of the user statistics table where the statistics will be retrieved

statid

Optional identifier associated with the statistics retrieved from the stattab

statown

Schema containing stattab (if different from current schema)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values in the user statistics table

ORA-20002: Bad user statistics table; may need to be upgraded

ORA-20003: Unable to import system statistics

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


IMPORT_TABLE_PREFS Procedure

This procedure is used to set the statistics preferences of the specified table in the specified schema.

Syntax

DBMS_STATS.IMPORT_TABLE_PREFS (
    ownname    IN  VARCHAR2,    tabname    IN  VARCHAR2,    stattab    IN  VARCHAR2,    statid     IN  VARCHAR2 DEFAULT NULL,    statown    IN  VARCHAR2 DEFAULT NULL);

Parameters

Table 140-62 IMPORT_TABLE_PREFS Procedure Parameters

Parameter Description

ownname

Owner name

tabname

Table name

stattab

Statistics table name from where to import the statistics

statid

(Optional) Identifier to associate with these statistics within stattab

statown

Schema containing stattab (if other than ownname)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

Usage Notes

Examples

DBMS_STATS.IMPORT_TABLE_PREFS('SH', 'SALES', 'STAT');

IMPORT_TABLE_STATS Procedure

This procedure retrieves statistics for a particular table from the user statistics table identified by stattab and stores them in the dictionary. Cascade results in all index statistics associated with the specified table being imported as well.

Syntax

DBMS_STATS.IMPORT_TABLE_STATS (
   ownname         VARCHAR2, 
   tabname         VARCHAR2,
   partname        VARCHAR2 DEFAULT NULL,
   stattab         VARCHAR2, 
   statid          VARCHAR2 DEFAULT NULL,
   cascade         BOOLEAN  DEFAULT TRUE,
   statown         VARCHAR2 DEFAULT NULL,
   no_invalidate   BOOLEAN DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   force           BOOLEAN DEFAULT FALSE,
   stat_category   VARCHAR2 DEFAULT DEFAULT_STAT_CATEGORY);

Parameters

Table 140-63 IMPORT_TABLE_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table

partname

Name of the table partition. If the table is partitioned and if partname is NULL, then global and partition table statistics are imported.

stattab

User statistics table identifier describing from where to retrieve the statistics

statid

Identifier (optional) to associate with these statistics within stattab

cascade

If true, column and index statistics for this table are also imported

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure

force

Imports statistics even if table statistics are locked

stat_category

Specifies what statistics to import, accepting multiple values separated by a comma. Values supported:

  • 'OBJECT_STATS' - table statistics, column statistics and index statistics (Default)

  • 'SYNOPSES' - auxiliary statistics information gathered on a partitioned table when incremental is TRUE


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values in the user statistics table

Usage Notes

Oracle does not support export or import of statistics across databases of different character sets.


LOCK_PARTITION_STATS Procedure

This procedure enables the user to lock statistics for a partition.

Syntax

DBMS_STATS.LOCK_PARTITION_STATS (
    ownname    VARCHAR2,
    tabname    VARCHAR2,
    partname   VARCHAR2);

Parameters

Table 140-64 LOCK_PARTITION_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema to lock

tabname

Name of the table

partname

Partition name



LOCK_SCHEMA_STATS Procedure

This procedure locks the statistics of all tables of a schema.

Syntax

DBMS_STATS.LOCK_SCHEMA_STATS (
   ownname    VARCHAR2);

Parameters

Table 140-65 LOCK_SCHEMA_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema to lock


Usage Notes

See "Usage Notes" for LOCK_TABLE_STATS Procedure.


LOCK_TABLE_STATS Procedure

This procedure locks the statistics on the table.

Syntax

DBMS_STATS.LOCK_TABLE_STATS (
   ownname    VARCHAR2,
   tabname    VARCHAR2);

Parameters

Table 140-66 LOCK_TABLE_STATS Procedure Parameters

Parameter Description

ownname

The name of the schema

tabname

The name of the table


Usage Notes


MERGE_COL_USAGE Procedure

This procedure merges column usage information from a source database by means of a dblink into the local database. If column usage information already exists for a given table or column MERGE_COL_USAGE will combine both the local and the remote information.

Syntax

DBMS_STATS.MERGE_COL_USAGE (
   dblink    IN    VARCHAR2);

Parameters

Table 140-67 MERGE_COL_USAGE Procedure Parameters

Parameter Description

dblink

Name of dblink


Usage Notes

User must be SYS to execute this procedure.

Exceptions

ORA-20000: Insufficient privileges

ORA-20001: Parameter dblink cannot be NULL

ORA-20002: Unable to create a TEMP table


PREPARE_COLUMN_VALUES Procedures

These procedures convert user-specified minimum, maximum, and histogram endpoint datatype-specific values into Oracle's internal representation for future storage using SET_COLUMN_STATS.

Syntax

DBMS_STATS.PREPARE_COLUMN_VALUES (
   srec     IN OUT StatRec, 
   charvals        CHARARRAY);

DBMS_STATS.PREPARE_COLUMN_VALUES (
   srec      IN OUT StatRec, 
   datevals         DATEARRAY);

DBMS_STATS.PREPARE_COLUMN_VALUES ( 
   srec     IN OUT StatRec, 
   dblvals         DBLARRAY);

DBMS_STATS.PREPARE_COLUMN_VALUES ( 
   srec     IN OUT StatRec, 
   fltvals         FLTARRAY);

DBMS_STATS.PREPARE_COLUMN_VALUES (
   srec     IN OUT StatRec, 
   numvals         NUMARRAY);

DBMS_STATS.PREPARE_COLUMN_VALUES ( 
   srec     IN OUT StatRec, 
   rawvals         RAWARRAY);

Pragmas

pragma restrict_references(prepare_column_values, WNDS, RNDS, WNPS, RNPS);
pragma restrict_references(prepare_column_values_nvarchar, WNDS, RNDS, WNPS, RNPS);
pragma restrict_references(prepare_column_values_rowid, WNDS, RNDS, WNPS, RNPS);

Parameters

Table 140-68 PREPARE_COLUMN_VALUES Procedure Parameters

Parameter Description

srec.epc

Number of values specified in charvals, datevals, dblvals, fltvals, numvals, or rawvals. This value must be between 2 and 256, inclusive, and it should be set to 2 for procedures which do not allow histogram information (nvarchar and rowid).

The first corresponding array entry should hold the minimum value for the column, and the last entry should hold the maximum. If there are more than two entries, then all the others hold the remaining height-balanced or frequency histogram endpoint values (with in-between values ordered from next-smallest to next-largest). This value may be adjusted to account for compression, so the returned value should be left as is for a call to SET_COLUMN_STATS.

srec.bkvals

If you want a frequency distribution, this array contains the number of occurrences of each distinct value specified in charvals, datevals, dblvals, fltvals, numvals, or rawvals. Otherwise, it is merely an output parameter, and it must be set to NULL when this procedure is called.


Datatype-specific input parameters (use one) are shown in Table 140-69.

Table 140-69 Datatype-Specific Input Parameters

Type Description

charvals

The array of values when the column type is character-based. Up to the first 32 bytes of each string should be provided. Arrays must have between 2 and 256 entries, inclusive. If the datatype is fixed CHAR, the strings must be space-padded to 15 characters for correct normalization.

datevals

Array of values when the column type is date-based

dblvals

Array of values when the column type is double-based

fltvals

Array of values when the column type is float-based

numvals

Array of values when the column type is numeric-based

rawvals

Array of values when the column type is RAW. Up to the first 32 bytes of each strings should be provided.

nvmin, nvmax

Minimum and maximum values when the column type is national character set based. No histogram information can be provided for a column of this type. If the datatype is fixed CHAR, the strings must be space-padded to 15 characters for correct normalization.

rwmin, rwmax

Minimum and maximum values when the column type is rowid. No histogram information is provided for a column of this type.


Output Parameters

Table 140-70 PREPARE_COLUMN_VALUES Procedure Output Parameters

Parameter Description

srec.minval

Internal representation of the minimum suitable for use in a call to SET_COLUMN_STATS

srec.maxval

Internal representation of the maximum suitable for use in a call to SET_COLUMN_STATS

srec.bkvals

Array suitable for use in a call to SET_COLUMN_STATS

srec.novals

Array suitable for use in a call to SET_COLUMN_STATS


Exceptions

ORA-20001: Invalid or inconsistent input values


PREPARE_COLUMN_VALUES_NVARCHAR2 Procedure

This procedure converts user-specified minimum, maximum, and histogram endpoint datatype-specific values into Oracle's internal representation for future storage using SET_COLUMN_STATS.

Syntax

DBMS_STATS.PREPARE_COLUMN_VALUES_NVARCHAR2 (
   srec     IN OUT StatRec, 
   nvmin           NVARCHAR2, 
   nvmax           NVARCHAR2);

Pragmas

pragma restrict_references(prepare_column_values_nvarchar, WNDS, RNDS, WNPS, RNPS);

Parameters

Table 140-71 PREPARE_COLUMN_VALUES_NVARCHAR2 Procedure Parameters

Parameter Description

srec.epc

Number of values specified in charvals, datevals, dblvals, fltvals, numvals, or rawvals. This value must be between 2 and 256, inclusive, and it should be set to 2 for procedures which do not allow histogram information (nvarchar and rowid).

The first corresponding array entry should hold the minimum value for the column, and the last entry should hold the maximum. If there are more than two entries, then all the others hold the remaining height-balanced or frequency histogram endpoint values (with in-between values ordered from next-smallest to next-largest). This value may be adjusted to account for compression, so the returned value should be left as is for a call to SET_COLUMN_STATS.

srec.bkvals

If you want a frequency distribution, then this array contains the number of occurrences of each distinct value specified in charvals, datevals, dblvals, fltvals, numvals, or rawvals. Otherwise, it is merely an output parameter, and it must be set to NULL when this procedure is called.


Datatype-specific input parameters (use one) are shown in Table 140-69.

Table 140-72 Datatype-Specific Input Parameters

Type Description

nvmin, nvmax

The minimum and maximum values when the column type is national character set based. No histogram information can be provided for a column of this type. If the datatype is fixed CHAR, the strings must be space-padded to 15 characters for correct normalization.


Output Parameters

Table 140-73 PREPARE_COLUMN_VALUES Procedure Output Parameters

Parameter Description

srec.minval

Internal representation of the minimum suitable for use in a call to SET_COLUMN_STATS

srec.maxval

Internal representation of the maximum suitable for use in a call to SET_COLUMN_STATS

srec.bkvals

Array suitable for use in a call to SET_COLUMN_STATS.

srec.novals

Array suitable for use in a call to SET_COLUMN_STATS


Exceptions

ORA-20001: Invalid or inconsistent input values


PREPARE_COLUMN_VALUES_ROWID Procedure

This procedure converts user-specified minimum, maximum, and histogram endpoint datatype-specific values into Oracle's internal representation for future storage using SET_COLUMN_STATS.

Syntax

DBMS_STATS.PREPARE_COLUMN_VALUES_ROWID (
   srec  IN OUT StatRec, 
   rwmin        ROWID, 
   rwmax        ROWID);

Pragmas

pragma restrict_references(prepare_column_values_rowid, WNDS, RNDS, WNPS, RNPS);

Parameters

Table 140-74 PREPARE_COLUMN_VALUES_ROWID Procedure Parameters

Parameter Description

srec.epc

Number of values specified in charvals, datevals, dblvals, fltvals, numvals, or rawvals. This value must be between 2 and 256, inclusive, and it should be set to 2 for procedures which do not allow histogram information (nvarchar and rowid).

The first corresponding array entry should hold the minimum value for the column, and the last entry should hold the maximum. If there are more than two entries, then all the others hold the remaining height-balanced or frequency histogram endpoint values (with in-between values ordered from next-smallest to next-largest). This value may be adjusted to account for compression, so the returned value should be left as is for a call to SET_COLUMN_STATS.

srec.bkvals

If you want a frequency distribution, this array contains the number of occurrences of each distinct value specified in charvals, datevals, dblvals, fltvals, numvals, or rawvals. Otherwise, it is merely an output parameter, and it must be set to NULL when this procedure is called.


Datatype-specific input parameters (use one) are shown in Table 140-69.

Table 140-75 Datatype-Specific Input Parameters

Type Description

rwmin, rwmax

Minimum and maximum values when the column type is rowid. No histogram information is provided for a column of this type.


Output Parameters

Table 140-76 PREPARE_COLUMN_VALUES Procedure Output Parameters

Parameter Description

srec.minval

Internal representation of the minimum suitable for use in a call to SET_COLUMN_STATS.

srec.maxval

Internal representation of the maximum suitable for use in a call to SET_COLUMN_STATS.

srec.bkvals

Array suitable for use in a call to SET_COLUMN_STATS.

srec.novals

Array suitable for use in a call to SET_COLUMN_STATS.


Exceptions

ORA-20001: Invalid or inconsistent input values


PUBLISH_PENDING_STATS Procedure

This procedure is used to publish the statistics gathered and stored as pending.

Syntax

DBMS_STATS.PUBLISH_PENDING_STATS (
    ownname         IN  VARCHAR2 DEFAULT USER,
    tabname         IN  VARCHAR2,
    no_invalidate   BOOLEAN DEFAULT 
       to_no_invalidate_type(get_param('NO_INVALIDATE')),
    force      IN  BOOLEAN DEFAULT FALSE);

Parameters

Table 140-77 PUBLISH_PENDING_STATS Procedure Parameters

Parameter Description

ownname

Owner name

tabname

Table name

no_invalidate

Do not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

If TRUE, will override the lock


Exceptions

ORA-20000: Insufficient privileges

Usage Notes

Examples

DBMS_STATS.PUBLISH_PENDING_STATS ('SH', null);

PURGE_STATS Procedure

This procedure purges old versions of statistics saved in the dictionary. To run this procedure, you must have the SYSDBA or both ANALYZE ANY DICTIONARY and ANALYZE ANY system privilege.

Syntax

DBMS_STATS.PURGE_STATS( 
    before_timestamp       TIMESTAMP WITH TIME ZONE);

Parameters

Table 140-78 PURGE_STATS Procedure Parameters

Parameter Description

before_timestamp

Versions of statistics saved before this timestamp are purged. If NULL, it uses the purging policy used by automatic purge. The automatic purge deletes all history older than the older of (current time - statistics history retention) and (time of recent analyze in the system - 1). The statistics history retention value can be changed using ALTER_STATS_HISTORY_RETENTION Procedure.The default is 31 days.


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values


RESET_GLOBAL_PREF_DEFAULTS Procedure

This procedures sets global preference, such as CASCADE, ESTIMATE_PERCENT and GRANULARITY, to default values. This reverses the global preferences set by the SET_GLOBAL_PREFS Procedure.

Syntax

DBMS_STATS.RESET_GLOBAL_PREF_DEFAULTS;

RESET_PARAM_DEFAULTS Procedure

Note:

This subprogram has been replaced by improved technology and is maintained only for purposes of backward compatibility. In this case, use the RESET_GLOBAL_PREF_DEFAULTS Procedure.

See also Deprecated Subprograms.

This procedure resets the default values of all parameters to Oracle recommended values.

Syntax

DBMS_STATS.RESET_PARAM_DEFAULTS;

RESTORE_DATABASE_STATS Procedure

This procedure restores statistics of all tables of the database as of a specified timestamp (as_of_timestamp).

Syntax

DBMS_STATS.RESTORE_DATABSE_STATS( 
   as_of_timestamp        TIMESTAMP WITH TIME ZONE, 
   force                  BOOLEAN DEFAULT FALSE,
   no_invalidate          BOOLEAN DEFAULT to_no_invalidate_type
                                                    (GET_PARAM('NO_INVALIDATE')));

Parameters

Table 140-79 RESTORE_DATABASE_STATS Procedure Parameters

Parameter Description

as_of_timestamp

The timestamp to which to restore statistics

force

Restores statistics even if their statistics are locked

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values

ORA-20006: Unable to restore statistics, statistics history not available


RESTORE_DICTIONARY_STATS Procedure

This procedure restores statistics of all dictionary tables (tables of 'SYS', 'SYSTEM' and RDBMS component schemas) as of a specified timestamp (as_of_timestamp).

Syntax

DBMS_STATS.RESTORE_DICTIONARY_STATS( 
   as_of_timestamp        TIMESTAMP WITH TIME ZONE, 
   force                  BOOLEAN DEFAULT FALSE,
   no_invalidate          BOOLEAN DEFAULT to_no_invalidate_type
                                                    (GET_PARAM('NO_INVALIDATE')));

Parameters

Table 140-80 RESTORE_DICTIONARY_STATS Procedure Parameters

Parameter Description

as_of_timestamp

Tmestamp to which to restore statistics

force

Restores statistics even if their statistics are locked

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.


Usage Notes

To run this procedure, you must have the SYSDBA or both ANALYZE ANY DICTIONARY and ANALYZE ANY system privilege.

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values

ORA-20006: Unable to restore statistics, statistics history not available


RESTORE_FIXED_OBJECTS_STATS Procedure

This procedure restores statistics of all fixed tables as of a specified timestamp (as_of_timestamp).

Syntax

DBMS_STATS.RESTORE_FIXED_OBJECTS_STATS( 
   as_of_timestamp        TIMESTAMP WITH TIME ZONE, 
   force                  BOOLEAN DEFAULT FALSE,
   no_invalidate          BOOLEAN DEFAULT to_no_invalidate_type
                                                    (GET_PARAM('NO_INVALIDATE')));

Parameters

Table 140-81 RESTORE_FIXED_OBJECTS_STATS Procedure Parameters

Parameter Description

as_of_timestamp

The timestamp to which to restore statistics

force

Restores statistics even if their statistics are locked

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.


Usage Notes

To run this procedure, you must have the SYSDBA or ANALYZE ANY DICTIONARY system privilege.

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values

ORA-20006: Unable to restore statistics, statistics history not available


RESTORE_SCHEMA_STATS Procedure

This procedure restores statistics of all tables of a schema as of a specified timestamp (as_of_timestamp).

Syntax

DBMS_STATS.RESTORE_SCHEMA_STATS( 
   ownname                VARCHAR2, 
   as_of_timestamp        TIMESTAMP WITH TIME ZONE, 
   force                  BOOLEAN DEFAULT FALSE,
   no_invalidate          BOOLEAN DEFAULT to_no_invalidate_type
                                                    (GET_PARAM('NO_INVALIDATE')));

Parameters

Table 140-82 RESTORE_SCHEMA_STATS Procedure Parameters

Parameter Description

ownname

Schema of the tables for which the statistics are to be restored

as_of_timestamp

The timestamp to which to restore statistics

force

Restores statistics even if their statistics are locked

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values

ORA-20006: Unable to restore statistics, statistics history not available


RESTORE_SYSTEM_STATS Procedure

This procedure restores system statistics as of a specified timestamp (as_of_timestamp).

Syntax

DBMS_STATS.RESTORE_SCHEMA_STATS( 
   as_of_timestamp        TIMESTAMP WITH TIME ZONE);

Parameters

Table 140-83 RESTORE_SYSTEM_STATS Procedure Parameters

Parameter Description

as_of_timestamp

The timestamp to which to restore statistics


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values

ORA-20006: Unable to restore statistics, statistics history not available


RESTORE_TABLE_STATS Procedure

This procedure restores statistics of a table as of a specified timestamp (as_of_timestamp). The procedure will restore statistics of associated indexes and columns as well. If the table statistics were locked at the specified timestamp the procedure will lock the statistics. The procedure will not restore user defined statistics.

Syntax

DBMS_STATS.RESTORE_TABLE_STATS (
   ownname                   VARCHAR2, 
   tabname                   VARCHAR2, 
   as_of_timestamp           TIMESTAMP WITH TIME ZONE,
   restore_cluster_index     BOOLEAN DEFAULT FALSE,
   force                     BOOLEAN DEFAULT FALSE,
   no_invalidate             BOOLEAN DEFAULT to_no_invalidate_type
                                                    (GET_PARAM('NO_INVALIDATE')));

Parameters

Table 140-84 RESTORE_TABLE_STATS Procedure Parameters

Parameter Description

ownname

The schema of the table for which the statistics are to be restored

tabname

The table name

as_of_timestamp

The timestamp to which to restore statistics

restore_cluster_index

If the table is part of a cluster, restore statistics of the cluster index if set to TRUE

force

Restores statistics even if the table statistics are locked. If the table statistics were not locked at the specified timestamp, it unlocks the statistics.

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent values

ORA-20006: Unable to restore statistics, statistics history not available


SEED_COL_USAGE Procedure

This procedure iterates over the SQL statements in the specified SQL tuning set, compiles them and seeds column usage information for the columns that appear in these statements.

Syntax

DBMS_STATS.SEED_COL_USAGE (
   sqlset_name    IN    VARCHAR2,   owner_name     IN    VARCHAR2,   time_limit     IN    POSITIVE DEFAULT NULL);

Parameters

Table 140-85 SEED_COL_USAGE Procedure Parameters

Parameter Description

sqlset_name

Name of the SQL tuning set

owner_name

Owner of the SQL tuning set

time_limit

Time limit (in seconds)


Exceptions

ORA-20000: Insufficient privileges


SET_COLUMN_STATS Procedures

This procedure sets column-related information. In the version of this procedure that deals with user-defined statistics, the statistics type specified is the type to store in the dictionary, in addition to the actual user-defined statistics. If this statistics type is NULL, the statistics type associated with the index or column is stored.

Syntax

DBMS_STATS.SET_COLUMN_STATS (
   ownname       VARCHAR2, 
   tabname       VARCHAR2, 
   colname       VARCHAR2, 
   partname      VARCHAR2 DEFAULT NULL,
   stattab       VARCHAR2 DEFAULT NULL, 
   statid        VARCHAR2 DEFAULT NULL,
   distcnt       NUMBER DEFAULT NULL,
   density       NUMBER DEFAULT NULL,
   nullcnt       NUMBER DEFAULT NULL,
   srec          StatRec DEFAULT NULL,
   avgclen       NUMBER DEFAULT NULL,
   flags         NUMBER DEFAULT NULL,
   statown       VARCHAR2 DEFAULT NULL,
   no_invalidate BOOLEAN DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   force         BOOLEAN DEFAULT FALSE);

Use the following for user-defined statistics:

DBMS_STATS.SET_COLUMN_STATS (
   ownname       VARCHAR2, 
   tabname       VARCHAR2, 
   colname       VARCHAR2, 
   partname      VARCHAR2 DEFAULT NULL,
   stattab       VARCHAR2 DEFAULT NULL, 
   statid        VARCHAR2 DEFAULT NULL,
   ext_stats     RAW,
   stattypown    VARCHAR2 DEFAULT NULL, 
   stattypname   VARCHAR2 DEFAULT NULL, 
   statown       VARCHAR2 DEFAULT NULL,
   no_invalidate BOOLEAN DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   force         BOOLEAN DEFAULT FALSE);

Parameters

Table 140-86 SET_COLUMN_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema.

tabname

Name of the table to which this column belongs.

colname

Name of the column or extension

partname

Name of the table partition in which to store the statistics. If the table is partitioned and partname is NULL, then the statistics are stored at the global table level.

stattab

User statistics table identifier describing where to store the statistics. If stattab is NULL, then the statistics are stored directly in the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

ext_stats

User-defined statistics

stattypown

Schema of the statistics type

stattypname

Name of the statistics type

distcnt

Number of distinct values

density

Column density. If this value is NULL and if distcnt is not NULL, then density is derived from distcnt.

nullcnt

Number of NULLs

srec

StatRec structure filled in by a call to PREPARE_COLUMN_VALUES or GET_COLUMN_STATS

avgclen

Average length for the column (in bytes)

flags

For internal Oracle use (should be left as NULL)

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

force

Sets the values even if statistics of the column are locked


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or inconsistent input values

ORA-20005: Object statistics are locked


SET_DATABASE_PREFS Procedure

This procedure is used to set the statistics preferences of all the tables, excluding the tables owned by Oracle. These tables can by included by passing TRUE for the add_sys parameter.

Syntax

DBMS_STATS.SET_DATABASE_PREFS (
    pname            IN   VARCHAR2,
    pvalue           IN   VARCHAR2,
    add_sys          IN   BOOLEAN DEFAULT FALSE);

Parameters

Table 140-87 SET_DATABASE_PREFS Procedure Parameters

Parameter Description

pname

Preference name. The default value for following parameters can be set:

  • CASCADE

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • PUBLISH

  • INCREMENTAL

  • STALE_PERCENT

.

CASCADE - Determines whether or not index statistics are collected as part of gathering table statistics.

.

DEGREE - Determines degree of parallelism used for gathering statistics.

.

ESTIMATE_PERCENT - Determines the percentage of rows to estimate. The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.

.

METHOD_OPT - Controls column statistics collection and histogram creation. It accepts either of the following options, or both in combination:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.
- column_name : Name of a column
- extension : Can be either a column group in the format of (column_name, colume_name [, ...]) or an expression

The default is FOR ALL COLUMNS SIZE AUTO.

.

NO_INVALIDATE - Controls the invalidation of dependent cursors of the tables for which statistics are being gathered. Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE to have Oracle decide when to invalidate dependent cursors. This is the default.

.

GRANULARITY - Determines granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - Gathers subpartition-level statistics.

.

PUBLISH - Determines whether or not newly gathered statistics will be published once the gather job has completed. Prior to Oracle Database 11g, Release 1 (11.1), once a statistic gathering job completed the new statistics were automatically published into the dictionary tables. The user now has the ability to gather statistics but not publish them immediately. This allows the DBA to test the new statistics before publishing them.

.

INCREMENTAL - Determines whether or not the global statistics of a partitioned table will be maintained without doing a full table scan. With partitioned tables it is very common to load new data into a new partition. As new partitions are added and data loaded, the global table statistics need to be kept up to date. Oracle will update the global table statistics by scanning only the partitions that have been changed instead of the entire table if the following conditions hold:

  • the INCREMENTAL value for the partitioned table is set to TRUE;

  • the PUBLISH value for the partitioned table is set to TRUE;

  • the user specifies AUTO_SAMPLE_SIZE for ESTIMATE_PERCENT and AUTO for GRANULARITY when gathering statistics on the table.

If the INCREMENTAL value for the partitioned table was set to FALSE (default value), a full table scan is used to maintain the global statistics which is a much more resource intensive and time-consuming operation for large tables.

.

STALE_PERCENT - Determines the percentage of rows in a table that have to change before the statistics on that table are deemed stale and should be regathered. The default value is 10%.

pvalue

Preference value. If NULL is specified, it will set the Oracle default value.s

add_sys

Value TRUE will include the Oracle-owned tables


Exceptions

ORA-20000: Insufficient privileges

ORA-20001: Invalid or illegal input values

Usage Notes

Examples

DBMS_STATS.SET_DATABASE_PREFS('CASCADE', 'DBMS_STATS.AUTO_CASCADE');
DBMS_STATS.SET_DATABASE_PREFS('ESTIMATE_PERCENT','9');
DBMS_STATS.SET_DATABASE_PREFS('DEGREE','99');

SET_GLOBAL_PREFS Procedure

This procedure is used to set the global statistics preferences.

Syntax

DBMS_STATS.SET_GLOBAL_PREFS (
    pname     IN   VARCHAR2,    pvalue    IN   VARCHAR2);

Parameters

Table 140-88 SET_GLOBAL_PREFS Procedure Parameters

Parameter Description

pname

Preference name. The default value for the following preferences can be set:

  • AUTOSTATS_TARGET

  • CASCADE

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • PUBLISH

  • INCREMENTAL

  • STALE_PERCENT

 

AUTOSTATS_TARGET - This preference is applicable only for auto statistics collection. The value of this parameter controls the objects considered for stats collection. It takes the following values:

  • 'ALL' - Statistics collected for all objects in system

  • 'ORACLE' - Statistics collected for all Oracle owned objects

  • 'AUTO' - Oracle decides on which objects to collect statistics

.

CASCADE - Determines whether or not index statistics are collected as part of gathering table statistics

.

DEGREE - Determines degree of parallelism used for gathering statistics

.

ESTIMATE_PERCENT - Determines the percentage of rows to estimate. The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.

.

METHOD_OPT - The value controls column statistics collection and histogram creation. It accepts either of the following options, or both in combination:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms.
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.
- column_name : Name of a column
- extension : Can be either a column group in the format of (column_name, colume_name [, ...]) or an expression

The default is FOR ALL COLUMNS SIZE AUTO.

.

NO_INVALIDATE - Controls the invalidation of dependent cursors of the tables for which statistics are being gathered. Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE to have Oracle decide when to invalidate dependent cursors. This is the default.

.

GRANULARITY - Determines granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- gathers partition-level statistics

'SUBPARTITION' - gathers subpartition-level statistics.

.

PUBLISH - This value determines whether or not newly gathered statistics will be published once the gather job has completed. Prior to Oracle Database 11g, Release 1 (11.1), once a statistic gathering job completed the new statistics were automatically published into the dictionary tables. The user now has the ability to gather statistics but not publish them immediately. This allows the DBA to test the new statistics before publishing them.

.

INCREMENTAL - This value determines whether or not the global statistics of a partitioned table will be maintained without doing a full table scan. With partitioned tables it is very common to load new data into a new partition. As new partitions are added and data loaded, the global table statistics need to be kept up to date. Oracle will update the global table statistics by scanning only the partitions that have been changed instead of the entire table if the following conditions hold:

  • INCREMENTAL value for the partitioned table is set to TRUE

  • PUBLISH value for the partitioned table is set to TRUE;

  • User specifies AUTO_SAMPLE_SIZE for ESTIMATE_PERCENT and AUTO for GRANULARITY when gathering statistics on the table

If the INCREMENTAL value for the partitioned table was set to FALSE (default value), a full table scan is used to maintain the global statistics which is a much more resource intensive and time-consuming operation for large tables.

.

STALE_PERCENT - Determines the percentage of rows in a table that have to change before the statistics on that table are deemed stale and should be regathered. The default value is 10%.

pvalue

Preference value. If NULL is specified, it will set the Oracle default value.s


Exceptions

ORA-20000: Insufficient privileges

ORA-20001: Invalid or illegal input values

Usage Notes

Examples

DBMS_STATS.SET_GLOBAL_PREFS('ESTIMATE_PERCENT','9');
DBMS_STATS.SET_GLOBAL_PREFS('DEGREE','99');

SET_INDEX_STATS Procedures

These procedures set index-related information. In the version of this procedure that deals with user-defined statistics, the statistics type specified is the type to store in the dictionary, in addition to the actual user-defined statistics. If this statistics type is NULL, the statistics type associated with the index or column is stored.

Syntax

DBMS_STATS.SET_INDEX_STATS (
   ownname       VARCHAR2, 
   indname       VARCHAR2,
   partname      VARCHAR2  DEFAULT NULL,
   stattab       VARCHAR2  DEFAULT NULL, 
   statid        VARCHAR2  DEFAULT NULL,
   numrows       NUMBER    DEFAULT NULL, 
   numlblks      NUMBER    DEFAULT NULL,
   numdist       NUMBER    DEFAULT NULL, 
   avglblk       NUMBER    DEFAULT NULL,
   avgdblk       NUMBER    DEFAULT NULL, 
   clstfct       NUMBER    DEFAULT NULL,
   indlevel      NUMBER    DEFAULT NULL, 
   flags         NUMBER    DEFAULT NULL,
   statown       VARCHAR2  DEFAULT NULL,
   no_invalidate BOOLEAN   DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   guessq        NUMBER    DEFAULT NULL,
   cachedblk     NUMBER    DEFAULT NULL,
   cachehit      NUMBER    DEFUALT NULL,
   force         BOOLEAN   DEFAULT FALSE);

Use the following for user-defined statistics:

DBMS_STATS.SET_INDEX_STATS (
   ownname       VARCHAR2, 
   indname       VARCHAR2,
   partname      VARCHAR2  DEFAULT NULL,
   stattab       VARCHAR2  DEFAULT NULL, 
   statid        VARCHAR2  DEFAULT NULL,
   ext_stats     RAW,
   stattypown    VARCHAR2 DEFAULT NULL, 
   stattypname   VARCHAR2 DEFAULT NULL, 
   statown       VARCHAR2 DEFAULT NULL,
   no_invalidate BOOLEAN DEFAULT to_no_invalidate_type(
                                    get_param('NO_INVALIDATE')),
   cachedblk     NUMBER    DEFAULT NULL,
   cachehit      NUMBER    DEFUALT NULL,
   force         BOOLEAN   DEFAULT FALSE);

Parameters

Table 140-89 SET_INDEX_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

indname

Name of the index

partname

Name of the index partition in which to store the statistics. If the index is partitioned and if partname is NULL, then the statistics are stored at the global index level.

stattab

User statistics table identifier describing where to store the statistics. If stattab is NULL, then the statistics are stored directly in the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

ext_stats

User-defined statistics

stattypown

Schema of the statistics type

stattypname

Name of the statistics type

numrows

Number of rows in the index (partition)

numlblks

Number of leaf blocks in the index (partition)

numdist

Number of distinct keys in the index (partition)

avglblk

Average integral number of leaf blocks in which each distinct key appears for this index (partition). If not provided, then this value is derived from numlblks and numdist.

avgdblk

Average integral number of data blocks in the table pointed to by a distinct key for this index (partition). If not provided, then this value is derived from clstfct and numdist.

clstfct

See clustering_factor column of the all_indexes view for a description

indlevel

Height of the index (partition)

flags

For internal Oracle use (should be left as NULL)

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

guessq

Guess quality. See the pct_direct_access column of the all_indexes view for a description.

cachedblk

The average number of blocks in the buffer cache for the segment (index/table/index partition/table partition)

cachehit

The average cache hit ratio for the segment (index/table/index partition/table partition)

force

Sets the values even if statistics of the index are locked


Usage Notes

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid input value

ORA-20005: Object statistics are locked


SET_PARAM Procedure

Note:

This subprogram has been replaced by improved technology and is maintained only for purposes of backward compatibility. In this case, use the SET_GLOBAL_PREFS Procedure.

See also Deprecated Subprograms.

This procedure sets default values for parameters of DBMS_STATS procedures. You can use the GET_PARAM Function to get the current default value of a parameter.

Syntax

DBMS_STATS.SET_PARAM (
   pname      IN    VARCHAR2, 
   pval       IN    VARCHAR2);

Parameters

Table 140-90 SET_PARAM Procedure Parameters

Parameter Description

pname

The parameter name The default value for following parameters can be set.

  • CASCADE - The default value for CASCADE set by SET_PARAM is not used by export/import procedures.It is used only by gather procedures.

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • AUTOSTATS_TARGET - This parameter is applicable only for auto statistics collection. The value of this parameter controls the objects considered for statistics collection (see pval)

pval

The parameter value. If NULL is specified, it will set the default value determined by Oracle. When pname is AUTOSTATS_TARGET, the following are valid values:

  • 'ALL' - Statistics are collected for all objects in the system

  • 'ORACLE' - Statistics are collected for all Oracle owned objects

  • 'AUTO' - Oracle decides for which objects to collect statistics


Usage Notes

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or illegal input value

Examples

DBMS_STATS.SET_PARAM('CASCADE','DBMS_STATS.AUTO_CASCADE');
DBMS_STATS.SET_PARAM('ESTIMATE_PERCENT','5');
DBMS_STATS.SET_PARAM('DEGREE','NULL');

SET_SCHEMA_PREFS Procedure

This procedure is used to set the statistics preferences of all the tables owned by the specified owner name.

Syntax

DBMS_STATS.SET_SCHEMA_PREFS (
    ownname   IN   VARCHAR2,
    pname     IN   VARCHAR2,    pvalue    IN   VARCHAR2);

Parameters

Table 140-91 SET_SCHEMA_PREFS Procedure Parameters

Parameter Description

ownname

Owner name

pname

Preference name. The default value for following parameters can be set:

  • CASCADE

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • PUBLISH

  • INCREMENTAL

  • STALE_PERCENT

pvalue

Preference value. If NULL is specified, it will set the Oracle default value.s


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or illegal input value

Usage Notes

Examples

DBMS_STATS.SET_SCHEMA_PREFS('SH','CASCADE', 'DBMS_STATS.AUTO_CASCADE');
DBMS_STATS.SET_SCHEMA_PREFS('SH' 'ESTIMATE_PERCENT','9');
DBMS_STATS.SET_SCHEMA_PREFS('SH', 'DEGREE','99');

SET_SYSTEM_STATS Procedure

This procedure sets systems statistics.

Syntax

DBMS_STATS.SET_SYSTEM_STATS (
   pname          VARCHAR2,
   pvalue         NUMBER,
   stattab   IN   VARCHAR2 DEFAULT NULL, 
   statid    IN   VARCHAR2 DEFAULT NULL,
   statown   IN   VARCHAR2 DEFAULT NULL);

Parameters

Table 140-92 SET_SYSTEM_STATS Procedure Parameters

Parameter Description

pname

The parameter name to get, which can have one of the following values:

  • iotfrspeed—I/O transfer speed in bytes for each millisecond

  • ioseektim - Seek time + latency time + operating system overhead time, in milliseconds

  • sreadtim - Average time to read single block (random read), in milliseconds

  • mreadtim - Average time to read an mbrc block at once (sequential read), in milliseconds

  • cpuspeed - Average number of CPU cycles for each second, in millions, captured for the workload (statistics collected using 'INTERVAL' or 'START' and 'STOP' options)

  • cpuspeednw - Average number of CPU cycles for each second, in millions, captured for the noworkload (statistics collected using 'NOWORKLOAD' option.

  • mbrc - Average multiblock read count for sequential read, in blocks

  • maxthr - Maximum I/O system throughput, in bytes/second

  • slavethr - Average slave I/O throughput, in bytes/second

pvalue

Parameter value to get

stattab

Identifier of the user statistics table where the statistics will be obtained. If stattab is null, the statistics will be obtained from the dictionary.

statid

Optional identifier associated with the statistics saved in the stattab

statown

Schema containing stattab (if different from current schema)


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid input value

ORA-20002: Bad user statistics table; may need to be upgraded

ORA-20003: Unable to set system statistics

ORA-20004: Parameter does not exist


SET_TABLE_PREFS Procedure

This procedure is used to set the statistics preferences of the specified table in the specified schema.

Syntax

DBMS_STATS.SET_TABLE_PREFS (
    ownname    IN  VARCHAR2,    tabname    IN  VARCHAR2,    pname      IN  VARCHAR2,    pvalue     IN  VARCHAR2);

Parameters

Table 140-93 SET_TABLE_PREFS Procedure Parameters

Parameter Description

ownname

Owner name

tabname

Table name

pname

Preference name. The default value for following preferences can be set:

  • CASCADE

  • DEGREE

  • ESTIMATE_PERCENT

  • METHOD_OPT

  • NO_INVALIDATE

  • GRANULARITY

  • PUBLISH

  • INCREMENTAL

  • STALE_PERCENT

.

CASCADE - Determines whether or not index statistics are collected as part of gathering table statistics.

.

DEGREE - Determines degree of parallelism used for gathering statistics.

.

ESTIMATE_PERCENT - Determines the percentage of rows to estimate. The valid range is [0.000001,100]. Use the constant DBMS_STATS.AUTO_SAMPLE_SIZE to have Oracle determine the appropriate sample size for good statistics. This is the default.

.

METHOD_OPT - Controls column statistics collection and histogram creation. It accepts either of the following options, or both in combination:

  • FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]

  • FOR COLUMNS [size clause] column [size_clause] [,column [size_clause]...]

size_clause is defined as size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}

column is defined as column := column_name | extension name | extension


- integer : Number of histogram buckets. Must be in the range [1,254].
- REPEAT : Collects histograms only on the columns that already have histograms
- AUTO : Oracle determines the columns to collect histograms based on data distribution and the workload of the columns.
- SKEWONLY : Oracle determines the columns to collect histograms based on the data distribution of the columns.
- column_name : Name of a column
- extension : Can be either a column group in the format of (column_name, colume_name [, ...]) or an expression

The default is FOR ALL COLUMNS SIZE AUTO.

.

NO_INVALIDATE - The value controls the invalidation of dependent cursors of the tables for which statistics are being gathered. Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE to have Oracle decide when to invalidate dependent cursors. This is the default.

.

GRANULARITY - Determines granularity of statistics to collect (only pertinent if the table is partitioned).

'ALL' - Gathers all (subpartition, partition, and global) statistics

'AUTO'- Determines the granularity based on the partitioning type. This is the default value.

'DEFAULT' - Gathers global and partition-level statistics. This option is obsolete, and while currently supported, it is included in the documentation for legacy reasons only. You should use the 'GLOBAL AND PARTITION' for this functionality. Note that the default value is now 'AUTO'.

'GLOBAL' - Gathers global statistics

'GLOBAL AND PARTITION' - Gathers the global and partition level statistics. No subpartition level statistics are gathered even if it is a composite partitioned object.

'PARTITION '- Gathers partition-level statistics

'SUBPARTITION' - Gathers subpartition-level statistics.

.

PUBLISH - Determines whether or not newly gathered statistics will be published once the gather job has completed. Prior to Oracle Database 11g, Release 1 (11.1), once a statistic gathering job completed the new statistics were automatically published into the dictionary tables. The user now has the ability to gather statistics but not publish them immediately. This allows the DBA to test the new statistics before publishing them.

.

INCREMENTAL - Determines whether or not the global statistics of a partitioned table will be maintained without doing a full table scan. With partitioned tables it is very common to load new data into a new partition. As new partitions are added and data loaded, the global table statistics need to be kept up to date. Oracle will update the global table statistics by scanning only the partitions that have been changed instead of the entire table if the following conditions hold:

  • INCREMENTAL value for the partitioned table is set to TRUE;

  • PUBLISH value for the partitioned table is set to TRUE;

  • User specifies AUTO_SAMPLE_SIZE for ESTIMATE_PERCENT and AUTO for GRANULARITY when gathering statistics on the table.

If the INCREMENTAL value for the partitioned table was set to FALSE (default value), a full table scan is used to maintain the global statistics which is a much more resource intensive and time-consuming operation for large tables.

.

STALE_PERCENT - Determines the percentage of rows in a table that have to change before the statistics on that table are deemed stale and should be regathered. The default value is 10%.

pvalue

Preference value. If NULL is specified, it will set the Oracle default value.


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid or illegal input values

Usage Notes

Examples

DBMS_STATS.SET_TABLE_PREFS('SH', 'SALES', 'CASCADE', 'DBMS_STATS.AUTO_CASCADE');
DBMS_STATS.SET_TABLE_PREFS('SH', 'SALES','ESTIMATE_PERCENT','9');
DBMS_STATS.SET_TABLE_PREFS('SH', 'SALES', 'DEGREE','99');

SET_TABLE_STATS Procedure

This procedure sets table-related information.

Syntax

DBMS_STATS.SET_TABLE_STATS (
   ownname       VARCHAR2, 
   tabname       VARCHAR2, 
   partname      VARCHAR2 DEFAULT NULL,
   stattab       VARCHAR2 DEFAULT NULL, 
   statid        VARCHAR2 DEFAULT NULL,
   numrows       NUMBER   DEFAULT NULL, 
   numblks       NUMBER   DEFAULT NULL,
   avgrlen       NUMBER   DEFAULT NULL, 
   flags         NUMBER   DEFAULT NULL,
   statown       VARCHAR2 DEFAULT NULL,
   no_invalidate BOOLEAN  DEFAULT to_no_invalidate_type (
                                     get_param('NO_INVALIDATE')),
   cachedblk     NUMBER    DEFAULT NULL,
   cachehit      NUMBER    DEFUALT NULL,
   force         BOOLEAN   DEFAULT FALSE);

Parameters

Table 140-94 SET_TABLE_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema

tabname

Name of the table

partname

Name of the table partition in which to store the statistics. If the table is partitioned and partname is NULL, then the statistics are stored at the global table level.

stattab

User statistics table identifier describing where to store the statistics. If stattab is NULL, then the statistics are stored directly in the dictionary.

statid

Identifier (optional) to associate with these statistics within stattab (Only pertinent if stattab is not NULL)

numrows

Number of rows in the table (partition)

numblks

Number of blocks the table (partition) occupies

avgrlen

Average row length for the table (partition)

flags

For internal Oracle use (should be left as NULL)

statown

Schema containing stattab (if different than ownname)

no_invalidate

Does not invalidate the dependent cursors if set to TRUE. The procedure invalidates the dependent cursors immediately if set to FALSE. Use DBMS_STATS.AUTO_INVALIDATE. to have Oracle decide when to invalidate dependent cursors. This is the default. The default can be changed using the SET_DATABASE_PREFS Procedure, SET_GLOBAL_PREFS Procedure, SET_SCHEMA_PREFS Procedure and SET_TABLE_PREFS Procedure.

cachedblk

The average number of blocks in the buffer cache for the segment (index/table/index partition/table partition)

cachehit

The average cache hit ratio for the segment (index/table/index partition/table partition)

force

Sets the values even if statistics of the table are locked


Usage Notes

Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Invalid input value

ORA-20005: Object statistics are locked


SHOW_EXTENDED_STATS_NAME Function

This function returns the name of the statistics entry that is created for the user-specified extension. It raises an error if no extension has been created.

Syntax

DBMS_STATS.SHOW_EXTENDED_STATS_NAME (
   ownname    VARCHAR2, 
   tabname    VARCHAR2,
   extension  VARCHAR2)
 RETURN VARCHAR2;

Parameters

Table 140-95 SHOW_EXTENDED_STATS_NAME Function Parameters

Parameter Description

ownname

Owner name of a table

tabname

Name of the table

extension

Can be either a column group or an expression. Suppose the specified table has two column c1, c2. An example column group can be "(c1, c2)" and an example expression can be "(c1 + c2)".


Exceptions

ORA-20000: Object does not exist or insufficient privileges

ORA-20001: Error when processing extension


UNLOCK_PARTITION_STATS Procedure

This procedure enables the user to unlock statistics for a partition.

Syntax

DBMS_STATS.UNLOCK_PARTITION_STATS (
    ownname    VARCHAR2,
    tabname    VARCHAR2,
    partname   VARCHAR2);

Parameters

Table 140-96 UNLOCK_PARTITION_STATS Procedure Parameters

Parameter Description

ownname

Name of the schema to unlock

tabname

Name of the table

partname

Partition name



UNLOCK_SCHEMA_STATS Procedure

This procedure unlocks the statistics on all the tables in schema.

Syntax

DBMS_STATS.UNLOCK_SCHEMA_STATS (
   ownname    VARCHAR2);

Parameters

Table 140-97 UNLOCK_SCHEMA_STATS Procedure Parameters

Parameter Description

ownname

The name of the schema


Usage Notes


UNLOCK_TABLE_STATS Procedure

This procedure unlocks the statistics on the table.

Syntax

DBMS_STATS.UNLOCK_TABLE_STATS (
   ownname    VARCHAR2,
   tabname    VARCHAR2);

Parameters

Table 140-98 UNLOCK_TABLE_STATS Procedure Parameters

Parameter Description

ownname

The name of the schema

tabname

The name of the table


Usage Notes


UPGRADE_STAT_TABLE Procedure

This procedure upgrades a user statistics table from an older version.

Syntax

DBMS_STATS.UPGRADE_STAT_TABLE (
   ownname    VARCHAR2,
   stattab    VARCHAR2);

Parameters

Table 140-99 UPGRADE_STAT_TABLE Procedure Parameters

Parameter Description

ownname

Name of the schema

stattab

Name of the table


Exceptions

ORA-20000: Unable to upgrade table