After Patching for Bug 28672124 Same SQL Has High CPU/Gets for Same # of Executions (Doc ID 2767851.1)

Last updated on MAY 06, 2022

Applies to:

Symptoms

After upgrading from 12.2 to 19c, queries ran two times slower in 19c than they had in 12.2   A query of awr_pdb_latch showed high waits for 'kokc descriptor allocation latch,' and a query of the mutex sleep history reported mostly mutex_type 'Row Cache' for location '[19] kqrpe'.  Applying a patch for <Bug 28672124> - PIPELINED FUNCTION CONSUMES MORE TIME IN 18C THEN 12.2.0.1 resolved the performance issue, but more than doubled the number of buffer gets (and thus CPU) for the same number of executions.

Bug 28672124 - PIPELINED FUNCTION CONSUMES MORE TIME IN 18C THEN 12.2.

Changes

 Upgrade to 19c plus application of patch for <Bug 28672124> - PIPELINED FUNCTION CONSUMES MORE TIME IN 18C THEN 12.2.0.1.  (See <Document 28672124.8> Bug 28672124 - Performance Issue From PLSQL Unit While Fetching Object Type To Collection Type for more information about this bug and the versions if affects.)

Cause

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