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Suboptimal Execution Plan When OR Expansion is Rejected due to LOB (Doc ID 2887904.1)

Last updated on AUGUST 18, 2022

Applies to:

Oracle Database - Enterprise Edition - Version 12.2.0.1 to 19.16.0.0.0 [Release 12.2 to 19]
Information in this document applies to any platform.

Symptoms

For SQL Query with LOB Column, "OR Expansion" is rejected, producing Sub-optimal Execution plan.

When "_optimizer_cbqt_or_expansion" is disabled it produces good plan.

When Cost Based OR Expansion(CBQT_ORE) is enabled, the Legacy ORE (i.e. Concatenation ) does not get applied.

 

Changes

 

Cause

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In this Document
Symptoms
Changes
Cause
Solution
References


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