Percona Server with XtraDB

accessing information_schema.partitions causes plans to change

Reported by Sergei Glushchenko on 2013-06-18
6
This bug affects 1 person
Affects Status Importance Assigned to Milestone
MySQL Server
Unknown
Unknown
Percona Server
Status tracked in 5.6
5.5
High
Sergei Glushchenko
5.6
High
Sergei Glushchenko

Bug Description

This is to track upstream bug http://bugs.mysql.com/bug.php?id=69179.
All credits to Justin Swanhart.

[9 May 4:22] Justin Swanhart
Description:
MySQL 5.6 supposed supports persistent statistics.

I enabled persistent statistics in my "my.cnf" and I also enabled them with the ALTER TABLE statement. However, in my testing, a read-only workload quickly resets the statistics as evidenced by query plans changes which result in severe performance loss.

In my testing, the first few batches of test queries will execute in 20 seconds or less with the data in the buffer pool, but then a batch of queries will start taking 80 seconds or more. An examination of the EXPLAIN plan on one of the queries in the batch shows a query plan change.

Reproduction steps are described in upstream bug report.

tags: added: upstream

In order to set triage, what is the reason for copying a MySQL bug to Percona Server bug db?

Found it.

Sergei -

Please submit the bugfixes to the upstream bug report.

Upstream fix in 5.5.34.

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