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                              WORKLOG TASK
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TASK...........: Push conditions down into non-mergeable VIEWs when possible
CREATION DATE..: Mon, 24 May 2010, 20:52
SUPERVISOR.....: Igor
IMPLEMENTOR....: 
COPIES TO......: Psergey, Timour
CATEGORY.......: Server-RawIdeaBin
TASK ID........: 119 (http://askmonty.org/worklog/?tid=119)
VERSION........: Server-9.x
STATUS.........: Un-Assigned
PRIORITY.......: 60
WORKED HOURS...: 0
ESTIMATE.......: 0 (hours remain)
ORIG. ESTIMATE.: 0

PROGRESS NOTES:



DESCRIPTION:

There are complaints (see links below) about cases with non-mergeable 
VIEW (because it has a GROUP BY), a query that has restrictions on 
the grouped column, and poor performance that is caused by VIEW 
processing code ignoring the restriction.

This WL is about addressing this issue.

links to complaints:
http://code.openark.org/blog/mysql/views-better-performance-with-condition-pushdown
http://www.mysqlperformanceblog.com/2010/05/19/a-workaround-for-the-performance-problems-of-temptable-views/

The target version is MariaDB 5.3+, because it has late optimization/execution
for FROM-subqueries/non mergeable VIEWs, which makes it much more feasible to
inject something into VIEW before it is optimized/executed.


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