MySQL hangs server completely
gmx at ross.cx
Wed May 22 18:29:17 UTC 2013
On Wed, 22 May 2013 15:52:45 +0200, Alejandro Imass <aimass at yabarana.com>
> We've been having this problem with a customer for a while and it
> seems that some funky query makes MySQL use 100% of CPU. Nevertheless,
> even though you can see in top that it's only 1 CPU in 100% (out of 8)
> the server eventually becomes useless and stops responding completely.
> So my question is, how does a user process hang the whole server? What
> system resources could MySQL be draining to make the server stop
> responding completely?
In laymans terms - can't do better - MySQL racing itself to obtain a (
table | memory | file ) lock?
I know I can death-stall the MySQL server at a customer's site if I give
it a big enough query ( like, DROPping a table, recreating it and pushing
backup data inside ) while cron's hourly backup-dump is running on the
database. Just the MySQL server, the machine itself hasn't stalled yet -
but I'm sitting at the console while doing this, so I don't know what
would eventually happen if I'd let it sit for a while.
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