Oracle 19c New Feature High-Frequency Statistics

The automatic optimizer statistics collection job which calls DBMS_STATS package runs in predefined maintenance windows and these maintenance windows are open once a day during which various jobs including the gathering of statistics is performed. For volatile tables statistics can go stale between two consecutive executions of such automatic statistics collection jobs. The presence of […]

Why do my execution plans not change after gathering statistics? – A look at Rolling Cursor Invalidations

In releases prior to Oracle 10g, the gathering of statistics using DBMS_STATS resulted in immediate invalidations of dependent cached cursors. This was true unless NO_INVALIDATE parameter of the DBMS_STATS command was set to TRUE. It was felt that gathering of statistics could actually have a negative impact on performance because of the fact that invalidation […]

Export and Import schema statistics

Easy way to export and import schema statistics – in case the optimizer is behaving strangely and you want to re-import old statistics when the optimizer behaved properly. SCHEMA NAME – TEST Create the table to store the statistics- EXEC DBMS_STATS.CREATE_STAT_TABLE(‘TEST’, ‘STATS_TABLE’); Export schema stats – will be stored in the ‘STATS_TABLE’ EXEC DBMS_STATS.export_schema_stats(‘TEST’,’STATS_TABLE’,NULL,’TEST’); If […]

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