Question on 19C Optimizer
Date: Sat, 24 Jul 2021 16:58:43 +0530
Message-ID: <CAKna9Vb6_UkT5_catpCDK_LvC4JH-T9PMO=T_2ixVo-9zcuHhg_at_mail.gmail.com>
Hello All, We don't have yet access to the database on which this issue is reproducible, but want to know here from experts if this below issue/bug has been encountered by anyone using 19C and thus has to be patched for safety.
We got complaints in which one third party application which frequently executes some big complex queries using many tables(10+ tables/views/subqueries etc) joins. And those are many times dynamically formed by that tool and submitted to the database. And those queries used to finish in a few seconds earlier(when DB version was 12.1.0.2 with OFE 11.2.0.4) but now in a lower environment which they try to test those queries before migration and is on 19C(19.9.0.0.0), it was observed by the team that those are running for hours and then have to be killed. And they are suspecting the below bug is impacting many of the queries for this application.
Bug 30537403 - Suboptimal Join Order for SQL Statements with Large Number of Tables (Doc ID 30537403.8)
This bug looks too generic and so we are a bit worried as we just can't go adding leading hints for all queries. But then considering so many application runs on the below 19.9 versions, wanted to know from experts here if this occurs only on certain situation? Or we really have to have patch for this before migrating to 19C?
Regards
Lok
-- http://www.freelists.org/webpage/oracle-lReceived on Sat Jul 24 2021 - 13:28:43 CEST