Insert As Select (IAS) Performs Worse in 18.1 than in 11.2.0.4 with UNION ALL PUSHED PREDICATE Operations
(Doc ID 2666004.1)
Last updated on APRIL 17, 2023
Applies to:
Oracle Database - Enterprise Edition - Version 18.5.0.0.0 and later
Information in this document applies to any platform.
Symptoms
- INSERT ... AS SELECT is not completing unless OFE is set to 11.2.0.4.
- In this case, setting "_optimizer_cartesian_enabled" = FALSE yields the best time found so far with OFE=18.1.0.
- The major differences between the fast and slow plans are
- - fast : 6 Merge Join Cartesian operations (MJC)
- - slow : 4 MJCs and 2 Union All Pushed Predicate operations
Changes
Upgrade from 11.2.0.4 to 18.1.
Cause
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