17 SEM_PERF Package Subprograms
The SEM_PERF package contains subprograms for examining and enhancing the performance of the Resource Description Framework (RDF) and Web Ontology Language (OWL) support in an Oracle database.
To use the subprograms in this chapter, you must understand the conceptual and usage information in RDF Semantic Graph Overview and OWL Concepts.
This chapter provides reference information about the subprograms, listed in alphabetical order.
- SEM_PERF.ANALYZE_AUX_TABLES
- SEM_PERF.DELETE_NETWORK_STATS
- SEM_PERF.DROP_EXTENDED_STATS
- SEM_PERF.EXPORT_NETWORK_STATS
- SEM_PERF.GATHER_STATS
- SEM_PERF.IMPORT_NETWORK_STATS
Parent topic: Reference Information
17.1 SEM_PERF.ANALYZE_AUX_TABLES
Format
SEM_PERF.ANALYZE_AUX_TABLES( model_name IN VARCHAR2, estimate_percent IN NUMBER DEFAULT DBMS_STATS.AUTO_SAMPLE_SIZE, method_opt IN VARCHAR2 DEFAULT NULL, degree IN NUMBER DEFAULT DBMS_STATS.AUTO_DEGREE, network_owner IN DBMS_ID DEFAULT NULL, network_name IN VARCHAR2 DEFAULT NULL);
Description
Analyzes all the SPM tables currently present for the given RDF model.
Parameters
- model_name
-
Name of the RDF model.
- estimate_percent
-
Determines the percentage of rows to sample. For more information on gathering the
estimate_percent
statistics, see DBMS_STATS.GATHER_TABLE_STATS procedure. - method_opt
-
Determines the column statistics collection. For more information on gathering the column statistics, see DBMS_STATS.GATHER_TABLE_STATS
- degree
-
Determines the degree of parallelism used for gathering statistics. For more information on this procedure parameter see DBMS_STATS.GATHER_TABLE_STATS
- network_owner
-
Owner of the semantic network. (See Table 1-1.)
- network_name
-
Name of the semantic network. (See Table 1-1.)
Usage Notes
Examples
The following example gathers statistics for SPM auxiliary tables.
EXECUTE SEM_PERF.ANALYZE_AUX_TABLES('m1',network_owner=>'RDFUSER',network_name=>'NET1');
Parent topic: SEM_PERF Package Subprograms
17.2 SEM_PERF.DELETE_NETWORK_STATS
Format
SEM_PERF.DELETE_NETWORK_STATS ( cascade_parts IN BOOLEAN DEFAULT TRUE, cascade_columns IN BOOLEAN DEFAULT TRUE, cascade_indexes IN BOOLEAN DEFAULT TRUE, no_invalidate IN BOOLEAN DEFAULT DBMS_STATS.AUTO_INVALIDATE, force IN BOOLEAN DEFAULT FALSE, options IN VARCHAR2 DEFAULT NULL, network_owner IN VARCHAR2 DEFAULT NULL, network_name IN VARCHAR2 DEFAULT NULL);
Description
Deletes statistics for the semantic network.
Parameters
- options
-
Controls the scope of the operation:
-
If
MDSYS.SDO_RDF.VALUE_TABLE_ONLY
, the operation applies only to the MDSYS.RDF_VALUE$ table. -
If
MDSYS.SDO_RDF.LINK_TABLE_ONLY
, the operation applies only to the MDSYS.RDF_LINK$ table. -
If null (the default), the operation applies to both the MDSYS.RDF_VALUE$ and MDSYS.RDF_LINK$ tables.
-
- (other parameters)
-
See the parameter explanations for the DBMS_STATS.DELETE_TABLE_STATS procedure in Oracle Database PL/SQL Packages and Types Reference, although
force
here applies to network statistics. - network_owner
-
Owner of the semantic network. (See Table 1-1.)
- network_name
-
Name of the semantic network. (See Table 1-1.)
Usage Notes
See the information about the DBMS_STATS package inOracle Database PL/SQL Packages and Types Reference.
See also Managing Statistics for Semantic Models and the Semantic Network.
For information about semantic network types and options, see Semantic Networks.
Examples
The following example deletes statistics for the semantic network:
EXECUTE SEM_APIS.DELETE_NETWORK_STATS;
Parent topic: SEM_PERF Package Subprograms
17.3 SEM_PERF.DROP_EXTENDED_STATS
Format
SEM_PERF.DROP_EXTENDED_STATS ( network_owner IN VARCHAR2 DEFAULT NULL, network_name IN VARCHAR2 DEFAULT NULL);
Description
Drops column groups used for extended optimizer statistics on the RDF_LINK$ table.
Parameters
Usage Notes
To use this procedure, you must connect as a user with permission to execute it. By default, when Spatial and Graph is installed as part of Oracle Database, only the MDSYS user can execute this procedure; however, execution permission on this procedure can be granted to users as needed.
The default column groups that will be dropped from RDF_LINK$ are: (CANON_END_NODE_ID, START_NODE_ID) (P_VALUE_ID, CANON_END_NODE_ID) (P_VALUE_ID, START_NODE_ID)
See also:
-
The information about the DBMS_STATS package in Oracle Database PL/SQL Packages and Types Reference
For information about semantic network types and options, see Semantic Networks.
Examples
The following example drops extended statistics for the semantic network:
EXECUTE SEM_PERF.DROP_EXTENDED_STATS;
Parent topic: SEM_PERF Package Subprograms
17.4 SEM_PERF.EXPORT_NETWORK_STATS
Format
SEM_PERF.EXPORT_NETWORK_STATS ( stattab IN VARCHAR2, statid IN VARCHAR2 DEFAULT NULL, cascade IN BOOLEAN DEFAULT TRUE, statown IN VARCHAR2 DEFAULT NULL, stat_category IN VARCHAR2 DEFAULT 'OBJECT_STATS', options IN VARCHAR2 DEFAULT NULL);
Description
Exports the statistics for the semantic network and stores them in the user statistics table.
Parameters
- options
-
Controls the scope of the operation:
-
If
MDSYS.SDO_RDF.VALUE_TABLE_ONLY
, the operation applies only to the MDSYS.RDF_VALUE$ table. -
If
MDSYS.SDO_RDF.LINK_TABLE_ONLY
, the operation applies only to the MDSYS.RDF_LINK$ table. -
If null (the default), the operation applies to both the MDSYS.RDF_VALUE$ and MDSYS.RDF_LINK$ tables.
-
- (other parameters)
-
See the parameter explanations for the DBMS_STATS.EXPORT_TABLE_STATS procedure in Oracle Database PL/SQL Packages and Types Reference.
- network_owner
-
Owner of the semantic network. (See Table 1-1.)
- network_name
-
Name of the semantic network. (See Table 1-1.)
Usage Notes
See the information about the DBMS_STATS package inOracle Database PL/SQL Packages and Types Reference.
See also Managing Statistics for Semantic Models and the Semantic Network.
For information about semantic network types and options, see Semantic Networks.
Examples
The following example exports the statistics for the semantic network and stores them in a table named STAT_TABLE
.
EXECUTE SEM_APIS.EXPORT_NETWORK_STATS('stat_table');
Parent topic: SEM_PERF Package Subprograms
17.5 SEM_PERF.GATHER_STATS
Format
SEM_PERF.GATHER_STATS( just_on_values_table IN BOOLEAN DEFAULT FALSE, degree IN NUMBER(38) DEFAULT NULL, estimate_percent IN NUMBER DEFAULT DBMS_STATS.AUTO_SAMPLE_SIZE, value_method_opt IN VARCHAR2 DEFAULT NULL, link_method_opt IN VARCHAR2 DEFAULT NULL, network_owner IN VARCHAR2 DEFAULT NULL, network_name IN VARCHAR2 DEFAULT NULL);
Description
Gathers statistics about RDF and OWL tables and their indexes.
Parameters
- just_on_values_table
-
TRUE
collects statistics only on the table containing the lexical values of triples;FALSE
(the default) collects statistics on all major tables related to the storage of RDF and OWL data.A value of
TRUE
reduces the execution time for the procedure; and it may be sufficient if you need only to collect statistics on the values table (for example, if you use other interfaces to collect any other statistics that you might need). - degree
-
Degree of parallelism. For more information about parallel execution, see Oracle Database VLDB and Partitioning Guide.
- estimate_percent
-
Determines the percentage of rows in MDSYS.RDF_LINK$ and MDSYS.RDF_VALUE$ to sample.
The valid range is between 0.000001 and 100. You can use the constant
DBMS_STATS.AUTO_SAMPLE_SIZE
(the default) to enable Oracle Database to determine the appropriate sample size for optimal statistics. - value_method_opt
-
Accepts either of the following options, or both in combination, for the MDSYS.RDF_VALUE$ table:
-
FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]
-
FOR COLUMNS [size clause] column|attribute [size_clause] [,column|attribute [size_clause]...]
size_clause
is defined as:size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}
column
is defined as:column := column_name | (extension)
-
integer
: Number of histogram buckets. Must be in the range [1, 2048]. -
REPEAT
: Collects histograms only on the columns that already have histograms. -
AUTO
: Oracle Database determines the columns to collect histograms based on data distribution and the workload of the columns. -
SKEWONLY
: Oracle Database 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, column_name [, ...]) or an expression.
The usual default is:
FOR ALL COLUMNS SIZE 2048
-
- link_method_opt
-
Accepts either of the following options, or both in combination, for the MDSYS.RDF_LINK$ table:
-
FOR ALL [INDEXED | HIDDEN] COLUMNS [size_clause]
-
FOR COLUMNS [size clause] column|attribute [size_clause] [,column|attribute [size_clause]...]
size_clause
is defined as:size_clause := SIZE {integer | REPEAT | AUTO | SKEWONLY}
column
is defined as:column := column_name | (extension)
-
integer
: Number of histogram buckets. Must be in the range [1,2048]. -
REPEAT
: Collects histograms only on the columns that already have histograms. -
AUTO
: Oracle Database determines the columns to collect histograms based on data distribution and the workload of the columns. -
SKEWONLY
: Oracle Database 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, column_name [, ...])
or an expression.
The usual default is:
FOR ALL COLUMNS SIZE AUTO FOR COLUMNS SIZE 2048 P_VALUE_ID CANON_END_NODE_ID START_NODE_ID G_ID (CANON_END_NODE_ID, START_NODE_ID) (P_VALUE_ID, CANON_END_NODE_ID) (P_VALUE_ID, START_NODE_ID)
-
- network_owner
-
Owner of the semantic network. (See Table 1-1.)
- network_name
-
Name of the semantic network. (See Table 1-1.)
Usage Notes
To use this procedure, you must connect as a user with permission to execute it. By default, when Spatial and Graph is installed as part of Oracle Database, only the MDSYS user can execute this procedure; however execution permission on this procedure can be granted to users as needed.
This procedure collects statistical information that can help you to improve inferencing performance, as explained in Enhancing Inference Performance. This procedure internally calls the DBMS_STATS.GATHER_TABLE_STATS procedure to collect statistics on RDF- and OWL-related tables and their indexes, and stores the statistics in the Oracle Database data dictionary. For information about using the DBMS_STATS package, see Oracle Database PL/SQL Packages and Types Reference.
Gathering statistics uses significant system resources, so execute this procedure when it cannot adversely affect essential applications and operations.
See also Managing Statistics for Semantic Models and the Semantic Network.
Examples
The following example gathers statistics about RDF and OWL related tables and their indexes.
EXECUTE SEM_PERF.GATHER_STATS;
Parent topic: SEM_PERF Package Subprograms
17.6 SEM_PERF.IMPORT_NETWORK_STATS
Format
SEM_PERF.IMPORT_NETWORK_STATS ( stattab IN VARCHAR2, statid IN VARCHAR2 DEFAULT NULL, cascade IN BOOLEAN DEFAULT TRUE, statown IN VARCHAR2 DEFAULT NULL, no_invalidate IN BOOLEAN DEFAULT FALSE, force IN BOOLEAN DEFAULT FALSE, stat_category IN VARCHAR2 DEFAULT 'OBJECT_STATS', options IN VARCHAR2 DEFAULT NULL, network_owner IN VARCHAR2 DEFAULT NULL, network_name IN VARCHAR2 DEFAULT NULL);
Description
Retrieves the statistics for the semantic network from a user statistics table and stores them in the dictionary.
Parameters
- options
-
Controls the scope of the operation:
-
If
MDSYS.SDO_RDF.VALUE_TABLE_ONLY
, the operation applies only to the MDSYS.RDF_VALUE$ table. -
If
MDSYS.SDO_RDF.LINK_TABLE_ONLY
, the operation applies only to the MDSYS.RDF_LINK$ table. -
If null (the default), the operation applies to both the MDSYS.RDF_VALUE$ and MDSYS.RDF_LINK$ tables.
-
- (other parameters)
-
See the parameter explanations for the DBMS_STATS.IMPORT_TABLE_STATS procedure in Oracle Database PL/SQL Packages and Types Reference, although
force
here applies to network statistics. - network_owner
-
Owner of the semantic network. (See Table 1-1.)
- network_name
-
Name of the semantic network. (See Table 1-1.)
Usage Notes
See the information about the DBMS_STATS package inOracle Database PL/SQL Packages and Types Reference.
See also Managing Statistics for Semantic Models and the Semantic Network.
For information about semantic network types and options, see Semantic Networks.
Examples
The following example imports the statistics for the semantic network in a table named STAT_TABLE
, and stores them in the dictionary.
EXECUTE SEM_APIS.IMPORT_NETWORK_STATS('stat_table');
Parent topic: SEM_PERF Package Subprograms