Poor Performance Of Native Full Outer Join
(Doc ID 731209.1)
Last updated on FEBRUARY 21, 2019
Applies to:Oracle Database - Enterprise Edition - Version 184.108.40.206 to 10.2.0.4 [Release 9.0.1 to 10.2]
Information in this document applies to any platform.
This problem can occur on any platform.
Performance of some queries using native full outer join syntax available since Oracle 9i version is slower for some queries compare with the equivalent queries rewritten as UNION ALL of two separate subqueries, i.e. without using full outer join syntax. In some cases performance difference could be two and more times.
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