Re: MySQL 5.6 update doubled IOs

[Dimitri Kravtchuk]

Hi Christian,

well, to compare apples-to-apples you should first:
- adapt your my.conf settings for both servers in the same way (there are many things left by default, and defaults are different in 5.5 and 5.6 (for ex. purge thread is off by default in 5.5, io capacity max is 2000 in 5.6 while it's not present in 5.5 and default io capacity is 200, etc. and so on..))

- application logic should be the same (so move these 3 tables to MyISAM as it was before -- MyISAM fully relays on your FS, and it'll not write any data until "flush" is not involved via MySQL or FS itself will decide to write modified data to the disk, but it happens in background and not involving any sync)..

- I'm very curious also about these "statements" you've executed on the dev-servers and they seem to run slower on 5.6 : do you have their EXPLAIN? execution time profile output? optimizer traces (for 5.6) ?

- also, is there any other processes than MySQL running on the server? do you have a "run queue" graph? (and CPU usage as well)..

Thank you for all these details!

Rgds,
-Dimitri