oracle table statistics - ghdrako/doc_snipets GitHub Wiki

• https://satya-dba.blogspot.com/2010/06/oracle-database-statistics-rbo-cbo.html Procedure | Collects -- | -- GATHER_INDEX_STATS | Index statistics GATHER_TABLE_STATS | Table, column, and index statistics GATHER_SCHEMA_STATS | Statistics for all objects in a schema GATHER_DICTIONARY_STATS | Statistics for all dictionary objects GATHER_DATABASE_STATS | Statistics for all objects in a database

EXEC DBMS_STATS.GATHER_DATABASE_STATS;
EXEC DBMS_STATS.GATHER_DATABASE_STATS(ESTIMATE_PERCENT=>20);

EXEC DBMS_STATS.GATHER_SCHEMA_STATS(ownname, estimate_percent, block_sample, method_opt, degree, granularity, cascade, stattab, statid, options, statown, no_invalidate, gather_temp, gather_fixed);
EXEC DBMS_STATS.GATHER_SCHEMA_STATS('SCOTT');
EXEC DBMS_STATS.GATHER_SCHEMA_STATS(OWNNAME=>'MRT');
EXEC DBMS_STATS.GATHER_SCHEMA_STATS('SCOTT',ESTIMATE_PERCENT=>10);

EXEC DBMS_STATS.GATHER_TABLE_STATS('SCOTT','EMP');
EXEC DBMS_STATS.GATHER_TABLE_STATS('SCOTT','EMP',ESTIMATE_PERCENT=>15);

EXEC DBMS_STATS.GATHER_INDEX_STATS('SCOTT','EMP_PK');
EXEC DBMS_STATS.GATHER_INDEX_STATS('SCOTT','EMP_PK',ESTIMATE_PERCENT=>15);

This package also gives us the ability to delete statistics:
EXEC DBMS_STATS.DELETE_DATABASE_STATS;
EXEC DBMS_STATS.DELETE_SCHEMA_STATS('SCOTT');
EXEC DBMS_STATS.DELETE_TABLE_STATS('SCOTT','EMP');
EXEC DBMS_STATS.DELETE_INDEX_STATS('SCOTT','EMP_PK');
EXEC DBMS_STATS.DELETE_PENDING_STATS('SH','SALES');

EXEC DBMS_STATS.GATHER_SCHEMA_STATS(OWNNAME=>'"DWH"',OPTIONS=>'GATHER AUTO');
EXEC DBMS_STATS.GATHER_SCHEMA_STATS(OWNNAME=>'PERFSTAT',CASCADE=>TRUE);

When gathering statistics on system schemas, we can use the procedure DBMS_STATS.GATHER_DICTIONARY_STATS. This procedure gathers statistics for all system schemas, including SYS and SYSTEM, and other optional schemas, such as CTXSYS and DRSYS.