I'll base my quick review on my older posts devoted to known bugs in MySQL 5.6.12 in three main areas: InnoDB, optimizer and replication. All quoted text below is taken from the release notes.
Let's start with InnoDB. From my "top 10" list I only see the following bug fixed in 5.6.13:
- Bug #69316. "Performance; InnoDB:
A code regression introduced in MySQL 5.6 negatively impacted
ALTER TABLEperformance. This could cause a performance drop between MySQL Server 5.5.x and 5.6.x. (Bug #16864741, Bug #69316)"
Now, let's move to replication. From my "top 10" replication bugs in 5.6.12 I see the following fixed:
- Bug #69369. "Replication: The condition leading to the issue fixed in Bug #16579083 continued to raise an error even though the condition itself no longer cause the issue to occur. (Bug #16931177, Bug #69369)."
- Bug #69341 . "Replication:
rpl_semi_sync_master_timeoutwas set to an extremely large value, semi-synchronous replication became very slow, especially when many sessions were working in parallel. It was discovered that the code to calculate this timeout was inside the wait loop itself, with the result that an increase in the value of
rpl_semi_sync_master_timeoutcaused repeated iterations. This fix improves the method used to calculate wakeup times, and moves it outside of the wait loop, so that it is executed one time only. (Bug #16878043, Bug #69341)"
- Bug #69096 - this actually fixed a minor remaining problem of referencing non-existent session variable, GTID_NEXT_LIST. The real problem was already fixed in 5.6.12 (see Bug #69045).
Finally, regression bugs in optimizer. The following are fixed in 5.6.13:
- Bug #69471. "When selecting a union of an empty result set (created with
WHERE FALSE) with a derived table, incorrect filtering was applied to the derived table. (Bug #69471, Bug #16961803)"
- Bug #69410. "For queries with
ORDER BY ... LIMIT, the optimizer could choose a nonordering index for table access. (Bug #69410, Bug #16916596)"
- Bug #68897. "Some
LEFT JOINqueries with
GROUP BYcould return incorrect results. (Bug #68897, Bug #16620047)".
Installation finished, time for real life checks (and more posts based on results):
C:\Program Files\MySQL\MySQL Server 5.5\bin>mysql -uroot -proot -P3314 test
Welcome to the MySQL monitor. Commands end with ; or \g.
Your MySQL connection id is 9
Server version: 5.6.13 MySQL Community Server (GPL)
Copyright (c) 2000, 2013, Oracle and/or its affiliates. All rights reserved.
Oracle is a registered trademark of Oracle Corporation and/or its
affiliates. Other names may be trademarks of their respective
Type 'help;' or '\h' for help. Type '\c' to clear the current input statement.
MySQL 5.6.13 looks promising enough from the first sight,and I surely hope new MySQL Cluster 7.3 release based on it (instead of a really much worse 5.6.11) is coming soon.