MySQL Performance Blog

It seems there is interesting problem with compatibility of MySQL binaries and binaries of third-party plugins.

I personally found and there is confirmation from InnoDB team that current InnoDB-plugin binaries do not work with lastest 5.1.24-rc binaries. It was very charming move from MySQL side to release new incompatible binary on the second day after the announce of InnoDB plugin. I do not think it was intentional, but still looks funny and shows broken communication between teams.

The more interesting becomes from Sergei Golubchik presentation on MySQL Conference, where Sergei says that in current API “versioning binds a plugin binary to specific server release”. That simply means that InnoDB has to release binary for each binary of MySQL. I suppose it should be changed, otherwise there will be total madness with versions - InnoDB 1.0.0 binary for MySQL 5.1.23, 5.1.24, …, InnoDB 1.0.1 binary for MySQL 5.1.23, 5.1.24, 5.1.25… etc.

Even when that is fixed I am looking forward to have good mess with double versioning and problems like “
MySQL version 5.X.Y does not work with InnoDB version 1.N.M, you need to upgrade InnoDB to version 1.N1.M1 or MySQL to version 5.X1.Y1″.

For a couple of months there have been no updates to our msl patch, however recently I managed some time to change this. The functionality was extended a little bit and what’s even more important the patch is available for all the recent MySQL releases.

To remind anyone who has not yet come across this piece of code. msl (microslow) patch was developed a few years ago to allow more precise logging of query execution times into the slow log. Originally MySQL database offered a second time resolution and also a 2 second minimum for the query to get written, that is when you set long_query_time=1. After applying the patch you could see whether the time was 0.005s or 0.9s, which can make a substantial difference for the database and application performance. Over time msl patch grew with new features to let people learn more details of query execution, normally hidden from everyone’s eyes. Currently it’s used by many DBAs and developers to help in optimizations or troubleshooting the applications. We ourselves often rely on it when doing commercial MySQL consulting and MySQL AB has even adopted it into the official database distribution starting 5.1.21 release.
[read more...]