Details
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Bug
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Status: Closed (View Workflow)
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Major
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Resolution: Won't Fix
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5.5.37, 10.0.11
Description
This is a separate issue to investigate possible performance degradation with semi-join as reported in MDEV-6239. We assume that MDEV-6239 is about partition pruning, and this bug will be about possible other issue.
Summary of data from comments and uploaded attachments for MDEV-6239:
MySQL_Myisam (reported response time: 1 sec)
- SJ-Materialization-lookup is used
- 842K rows read
Maria_Myisam_Optimizer_off (reported resp. time 1 second)
- Materialization is used.
- 842K row reads.
Maria_Myisam_Optimizer_On (reported resp. time 23 seconds)
- LooseScan is used.
- 7.5M row reads.
(Need to retry this query with partition pruning fix. Maybe, the optimizer
will figure that query plan with LooseScan is not optimal and pick a
different plan)
Maria_Toku_Optimizer_Off (reported resp. time 10 sec)
- Materialization is used
- 845K reads
Maria_Toku_Optimizer_On (reported resp. time 5 sec)
- Materialization is used
- 842K reads
Attachments
Issue Links
- relates to
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MDEV-6239 Partition pruning is not working as expected in an inner query
- Closed