My Oracle Support Banner

Performance Issues With Parallel Queries And TEMP TABLE TRANSFORMATION (Doc ID 1633759.1)

Last updated on FEBRUARY 01, 2022

Applies to:

Oracle Database Cloud Schema Service - Version N/A and later
Oracle Database Exadata Express Cloud Service - Version N/A and later
Oracle Database Exadata Cloud Machine - Version N/A and later
Oracle Database Cloud Exadata Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.

Symptoms

Statements running in parallel can take significant time compare to the run in serial.
Parallel run does not complete for 20 minutes whereas the same statements when run after disabling parallel will complete in 20-30 seconds.

The Plan Table shows usage of Temp table transformation during load


pstack of the parallel process shows the below kcbrbo and qertbFetch

Cause

To view full details, sign in with your My Oracle Support account.

Don't have a My Oracle Support account? Click to get started!


In this Document
Symptoms
Cause
Solution
References


My Oracle Support provides customers with access to over a million knowledge articles and a vibrant support community of peers and Oracle experts.