MySQL custom configuration

[akostadinov]

Missing Information

Need information how to apply custom MySQL server configuration to the cimg/mysql image.

My observation is that mysql takes 500+ MB of RAM for a mostly empty test database. This is too much and causes OOM in tests where also chrome, redis, memcached and manticore are run at the same time. And MySQL is the biggest memory user (except chrome).

I read that some options like table_definition_cache = 400 may help significantly reduce its footprint. So wanted to try. But I see no way to apply such options.

Already Looked

https://circleci.com/docs/databases/
https://circleci.com/developer/images/image/cimg/mysql#how-this-image-works

Potential Locations

both of the above

[rosieyohannan]

Hi @akostadinov thank you for flagging this up to us. I will see what I can find out to help 👍

[akostadinov]

FYI I managed to supply startup options like this:
https://github.com/3scale/porta/blob/ad209e2004d7320daf28f8d751fb19bb32407bc7/.circleci/config.yml#L104-L110

[rosieyohannan]

Thanks for posting your solution. I will add an example to the "Configuring databases" page 👍

[akostadinov]

@rosieyohannan , while my personal issue is now resolved, CircleCI may save a good amount of shared resources if you adjust your mysql image default settings. Seem like by default MySQL can easily eat half GB RAM while most test suites would not require more than 50-100. I just don't have the time and need to optimize this further than I did. But maybe it's worth looking at for your infrastructure. Just my 2 cents.