MySQL weirdness
September 21st, 2007
It seems that MySQL folks began to use the same style of doing things that PHP project use. E.g. fixing one bug by introducing another one, two or more. That's a pity, though MySQL was never a high-quality project...
The problem I recenltly run into at Hosting Telesystems by upgrading our web hosting DBMS servers lie in the fact that the shiny new 5.0.45 version of MySQL silently ignores "tmpdir" value setting and put temporary tables in it's working dir. Our configuration used a memory disk for these purposes before, so this fault created a very high load on the storage disk, not speaking of increased request processing times. It's definitely not a good way of making things...
Hopefully, the fix for this bug has been already committed to MySQL CVS, so I made a patch of that and send it to ale (FreeBSD port maintainer). I beleive he'll commit it soon:-)
For those who is intrested, patches for mysql itself (agains 5.0.45 release) also available here:
http://people.FreeBSD.org/~stas/patch-sql_sql_select.cc
http://people.FreeBSD.org/~stas/patch-sql_item.cc
PS: Am I only one who thinks that putting temp tables on disk is a bad idea of memory management? Who the hell ivented this? Why not simply use a memory mapped file to put temporary data on it and let the VM system optimize things out?