[MDEV-193] LP:944706 - Query with impossible or constant subquery in WHERE or HAVING is not precomputed and thus not part of optimization Created: 2012-03-21  Updated: 2012-06-19  Resolved: 2012-06-19

Status: Closed
Project: MariaDB Server
Component/s: None
Affects Version/s: None
Fix Version/s: 5.5.25

Type: Bug Priority: Minor
Reporter: Elena Stepanova Assignee: Timour Katchaounov (Inactive)
Resolution: Fixed Votes: 0
Labels: None

Issue Links:
Relates
relates to MDEV-277 CHEAP SQ: Server crashes in st_join_t... Closed
relates to MDEV-287 CHEAP SQ: A query with subquery in SE... Closed
relates to MDEV-288 CHEAP SQ: Valgrind warnings "Memory l... Closed
relates to MDEV-311 CHEAP SQ: Inconsistent behavior of su... Closed
relates to MDEV-312 CHEAP SQ: A query with LEFT JOIN in o... Closed
relates to MDEV-317 CHEAP SQ: A query with EXISTS subquer... Closed
relates to MDEV-321 CHEAP SQ: A query with inner joins an... Closed

 Description   

https://bugs.launchpad.net/maria/+bug/944706

This is not a new bug, but it has been recently switched from milestone 5.3 to 5.5, so it needs an entry in JIRA.
Fix version 5.5.23 is temporary.

 Comments   
Comment by Timour Katchaounov (Inactive) [ 2012-03-28 ]

Fixed all crashes resulting from enabling back subquery execution during query optimization.
The result of the fixes is that now I need to find a new solution for bug https://bugs.launchpad.net/maria/+bug/944504, because its current fix is to forbid subquery evaluation during optimization.

After fixing this remaining crash (bug lp:944504), there are several wrong results to be fixed.
After that, the patch needs improvement in how we detect if a subquery is expensive, and to refine two of the fixes for EXPLAIN-specific crashes.

Comment by Timour Katchaounov (Inactive) [ 2012-06-19 ]
  • Analyzed EXPLAIN differences due to merge
  • Finished mere, pushed into 5.5.25.
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