9.60 V$SQL_PLAN_MONITOR

V$SQL_PLAN_MONITOR displays plan level monitoring statistics for each SQL statement found in V$SQL_MONITOR. Each row in V$SQL_PLAN_MONITOR corresponds to an operation of the execution plan being monitored. As with V$SQL_MONITOR, statistics exposed in V$SQL_PLAN_MONITOR are generally updated every second when the statement executes. These statistics are recycled on the same basis as V$SQL_MONITOR.

To eliminate the overhead of SQL plan monitoring, statistics collected for each operation of the plan do not record timing information such as elapsed time, CPU time, or I/O time. Instead, this timing information can be estimated quite accurately by joining V$SQL_PLAN_MONITOR with V$ACTIVE_SESSION_HISTORY on SQL_ID, SQL_EXEC_START, SQL_EXEC_ID, and SQL_PLAN_LINE_ID (simply named PLAN_LINE_ID in V$SQL_PLAN_MONITOR). The result of that join is a sample of the activity performed by each operation in the plan, from which an estimate of CPU time and wait time can be derived. This can be achieved by breaking statement level monitoring time statistics found in V$SQL_MONITOR in proportion to the number of samples found in V$ACTIVE_SESSION_HISTORY for the corresponding activity type.

Column Datatype Description

CON_ID

NUMBER

The ID of the container to which the data pertains. Possible values include:

  • 0: This value is used for rows containing data that pertain to the entire CDB. This value is also used for rows in non-CDBs.

  • 1: This value is used for rows containing data that pertain to only the root

  • n: Where n is the applicable container ID for the rows containing data

KEY

NUMBER

Foreign key to efficiently join V$SQL_PLAN_MONITOR with V$SQL_MONITOR (see V$SQL_MONITOR)

STATUS

VARCHAR2(19)

SQL execution status:

  • EXECUTING - SQL statement is still executing

  • DONE (ERROR) - Execution terminated with an error

  • DONE (FIRST N ROWS) - Execution terminated by the application before all rows were fetched

  • DONE (ALL ROWS) - Execution terminated and all rows were fetched

  • DONE - Execution terminated (parallel execution)

FIRST_REFRESH_TIME

DATE

Time when monitoring of the SQL statement started

LAST_REFRESH_TIME

DATE

Time when statistics were last updated for the SQL statement

FIRST_CHANGE_TIME

DATE

First time a row was produced by this operation

LAST_CHANGE_TIME

DATE

Last time a row was produced by this operation

REFRESH_COUNT

NUMBER

Number of times statistics have been refreshed

SID

NUMBER

Session identifier executing (or having executed) the SQL statement being monitored

PROCESS_NAME

VARCHAR2(5)

Process name identifier

SQL_ID

VARCHAR2(13)

SQL identifier

SQL_EXEC_START

DATE

Time when the execution started

SQL_EXEC_ID

NUMBER

Execution identifier

SQL_PLAN_HASH_VALUE

NUMBER

SQL plan hash value

SQL_CHILD_ADDRESS

RAW(4 | 8)

Address of the child cursor

PLAN_PARENT_ID

NUMBER

ID of the next execution step that operates on the output of the current step

PLAN_LINE_ID

NUMBER

Plan line number for the entry

PLAN_OPERATION

VARCHAR2(30)

Plan operation name (from V$SQL_PLAN)

PLAN_OPTIONS

VARCHAR2(30)

Plan option name (from V$SQL_PLAN)

PLAN_OBJECT_OWNER

VARCHAR2(128)

Name of the user who owns the schema containing the table or index

PLAN_OBJECT_NAME

VARCHAR2(128)

Name of the table or index

PLAN_OBJECT_TYPE

VARCHAR2(80)

Type of the object

PLAN_DEPTH

NUMBER

Depth (or level) of the operation in the tree. It is not necessary to issue a CONNECT BY statement to get the level information, which is generally used to indent the rows from the PLAN_TABLE table. The root operation (statement) is level 0.

PLAN_POSITION

NUMBER

Order of processing for all operations that have the same PARENT_ID

PLAN_COST

NUMBER

Cost of the operation as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is NULL.

PLAN_CARDINALITY

NUMBER

Estimate, by the cost-based optimizer, of the number of rows produced by the operation

PLAN_BYTES

NUMBER

Estimate, by the cost-based optimizer, of the number of bytes produced by the operation

PLAN_TIME

NUMBER

Elapsed time (in seconds) of the operation as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is NULL.

PLAN_PARTITION_START

VARCHAR2(256)

Start partition of a range of accessed partitions

PLAN_PARTITION_STOP

VARCHAR2(256)

Stop partition of a range of accessed partitions

PLAN_CPU_COST

NUMBER

CPU cost of the operation as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is NULL.

PLAN_IO_COST

NUMBER

I/O cost of the operation as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is NULL.

PLAN_TEMP_SPACE

NUMBER

Temporary space usage of the operation (sort or hash-join) as estimated by the optimizer's cost-based approach. For statements that use the rule-based approach, this column is NULL.

STARTS

NUMBER

Number of times this operation was executed. For example, an operation is executed multiple times when it is on the right side of a nested-loop join (once for each row of the left input of that nested-loop join).

OUTPUT_ROWS

NUMBER

Number of rows produced by this operation since the execution started. This number is cumulated for all executions of this operation. Divide by the value of the STARTS column to compute the average number of rows per execution of the operation. Note that the value in the STARTS column is equal to or higher than the value in the OUTPUT_ROWS column. The value will usually be equal, but depending on internal optimizations a higher value may be seen.

IO_INTERCONNECT_BYTES

NUMBER

Number of I/O bytes exchanged between Oracle Database and the storage system. Maintained only after Oracle starts to monitor the execution.

PHYSICAL_READ_REQUESTS

NUMBER

Number of physical read I/O requests issued by the monitored SQL. Maintained only after Oracle starts to monitor the execution.

PHYSICAL_READ_BYTES

NUMBER

Number of bytes read from disks by the monitored SQL. Maintained only after Oracle starts to monitor the execution.

PHYSICAL_WRITE_REQUESTS

NUMBER

Number of physical write I/O requests issued by the monitored SQL. Maintained only after Oracle starts to monitor the execution.

PHYSICAL_WRITE_BYTES

NUMBER

Number of bytes written to disks by the monitored SQL. Maintained only after Oracle starts to monitor the execution.

WORKAREA_MEM

NUMBER

Amount of memory (in bytes) used by the operation when the query is executing; NULL if the execution is done. This applies only to operations using a work area, such as sort, hash-join, group-by, and so on.

WORKAREA_MAX_MEM

NUMBER

Maximum value (in bytes) for WORKAREA_MEM; NULL if the operation is not using a work area. When the execution is finished, this value will hold the maximum amount of memory consumed by this operation during the execution of the statement.

WORKAREA_TEMPSEG

NUMBER

Amount of temporary space (in bytes) used by the operation when the query is executing; NULL if the operation has not spilled to disk or if the execution is finished

WORKAREA_MAX_TEMPSEG

NUMBER

Maximum value (in bytes) for WORKAREA_TEMPSEG; NULL if this operation never spilled to disk. When the execution is done, this value will hold the maximum amount of temporary space consumed by this operation during the entire execution.

OTHERSTAT_GROUP_ID

NUMBER

Plan line statistic group identifier (see GROUP_ID column in V$SQL_MONITOR_STATNAME)

OTHERSTAT_1_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 1 of that plan line

OTHERSTAT_1_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_1_VALUE

NUMBER

Value of statistic number 1 of that plan line

OTHERSTAT_2_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 2 of that plan line

OTHERSTAT_2_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_2_VALUE

NUMBER

Value of statistic number 2 of that plan line

OTHERSTAT_3_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 3 of that plan line

OTHERSTAT_3_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_3_VALUE

NUMBER

Value of statistic number 3 of that plan line

OTHERSTAT_4_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 4 of that plan line

OTHERSTAT_4_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_4_VALUE

NUMBER

Value of statistic number 4 of that plan line

OTHERSTAT_5_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 5 of that plan line

OTHERSTAT_5_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_5_VALUE

NUMBER

Value of statistic number 5 of that plan line

OTHERSTAT_6_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 6 of that plan line

OTHERSTAT_6_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_6_VALUE

NUMBER

Value of statistic number 6 of that plan line

OTHERSTAT_7_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 7 of that plan line

OTHERSTAT_7_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_7_VALUE

NUMBER

Value of statistic number 7 of that plan line

OTHERSTAT_8_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 8 of that plan line

OTHERSTAT_8_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_8_VALUE

NUMBER

Value of statistic number 8 of that plan line

OTHERSTAT_9_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 9 of that plan line

OTHERSTAT_9_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_9_VALUE

NUMBER

Value of statistic number 9 of that plan line

OTHERSTAT_10_ID

NUMBER

Statistic identifier (see ID column in V$SQL_MONITOR_STATNAME) for statistic number 10 of that plan line

OTHERSTAT_10_TYPE

NUMBER

Reserved for internal use

OTHERSTAT_10_VALUE

NUMBER

Value of statistic number 10 of that plan line

OTHER_XML

CLOB

Provides extra information specific to an execution step of the execution plan. The content of this column is structured using XML because it allows multiple pieces of information to be stored, including the following:

  • Name of the schema against which the query was parsed

  • Release number of the Oracle Database that produced the explain plan

  • Hash value associated with the execution plan

  • Name (if any) of the outline or the SQL profile used to build the execution plan

  • Indication of whether or not dynamic statistics were used to produce the plan

  • The outline data, a set of optimizer hints that can be used to regenerate the same plan

PLAN_OPERATION_INACTIVE

NUMBER

Indicates whether this plan operation was part of the final resolved plan