Re: 5.1 to 5.5 upgrade causes significant write slowdown (MyISAM + indexes)

[Ben Wallach]

Well, I am not sure we are going to see a big difference in basic read/write speed (between the 2 environments). Although I will try this.

Here's why:
When we removed the indexes on one of the tables, we saw no performance differences between the 2 envoironments (see earlier in the thread). So this initally led us to believe that this is a MySQL 5.5/index write issue (thus this posting). However, since the old hardware (with same OS and MySQL 5.5 installed) has no issues with or without indexes, we are now leaning torwards this being a hardware problem. A problem that only shows itself when indexes are being written.

Perhaps some chasis/disk/raid threshold is reached (during index creation)? I know this sounds strange, but how else to explain same software install (OS+MySQL) working fine on old and not working fine on new..and yet at the same time, both work fine without index creation..