As cost analysis reason the Optimizer choose to use "UNION-ALL PARTITION" instead of "UNION ALL PUSHED PREDICATE"
(Doc ID 3063761.1)
Last updated on DECEMBER 24, 2024
Applies to:
Oracle Database - Enterprise Edition - Version 19.10.0.0.0 and laterGen 2 Exadata Cloud at Customer - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Information in this document applies to any platform.
Symptoms
The select statements having cursor part of it, the Oracle Optimizer is not using Pushed predicate option like it used to do for select statement with out cursor involved in it.
So
• After upgrading their database to version 19, the customer encounters performance issues with select statements containing cursor expressions.
• The Oracle optimizer fails to utilize the "pushed predicate" option, which was previously effective for select statements without cursors.
• This issue is accompanied by the appearance of the "UNION-ALL PARTITION" path instead of the expected "UNION ALL PUSHED PREDICATE".
Changes
select
cursor(select dummy from dual) dummy, <<<< use cursor expression <<<
Cause
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In this Document
| Symptoms |
| Changes |
| Cause |
| Solution |
| References |