Why Didn't My Parallel Query Use the Expected Number of Slaves?
(Doc ID 199272.1)
Last updated on NOVEMBER 07, 2023
Applies to:
Oracle Database Cloud Schema Service - Version N/A and later Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later Oracle Cloud Infrastructure - Database Service - 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.
Purpose
This article explains what to check if a query does not use the expected number of parallel query slaves. It explains :
How to find the number of slaves that were used
What affects the number of query slaves used
How to trace query slave allocation
The word 'query' is used in relation to any type of SQL statement. The terms 'parallel execution slave', 'parallel slave', 'slave', 'parallel execution server' all mean the same thing. This article does not cover queries running in an OPS environment.
Troubleshooting Steps
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