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From:Dan Nelson Date:January 12 2011 5:33pm
Subject:Re: mySQLdump has a lot of variation for time to complete
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In the last episode (Jan 12), Feighen Oosterbroek said:
> I know that this is a bit of a vague question, but over a period of days
> mysqldump will take on one day 2min to complete and on the following day
> 25min to complete, with the resulting sql file being maybe 200M bigger. 
> The dataset isn't really all that large 14Gb on disk with the dump files
> being around 7G gzipped down to ~700M.  What I'd like to know is how can I
> check to see what is causing the slowness on any given day, or, if indeed,
> there is something I can check.

If you are dumping myisam tables, mysqldump's SELECT statements will queue
up behind INSERTs just like any other query, and if you happen to have
kicked off an UPDATE that takes 20 minutes to run, your dump will have an
elapsed time of 25 minutes just because it had to wait to the UPDATE to
finish.  If you are on the system on a day that it's taking a long time to
run, run some "show processlist" commands and see if there are any INSERT or
UPDATEs running.

	Dan Nelson
mySQLdump has a lot of variation for time to completeFeighen Oosterbroek12 Jan
  • Re: mySQLdump has a lot of variation for time to completeDan Nelson12 Jan