On Oct 22, 2009, at 3:26 PM, Eddie Drapkin wrote:
On Thu, Oct 22, 2009 at 4:14 PM, Philip Thompson <philthathril@xxxxxxxxx
> wrote:
Hi all.
I'm running into a random issue where sometimes it take several
minutes (up
to 10 or 15) to complete a query. According to 1 or 2 references,
this may
be a mysql bug. These links explain the similar problem I'm
experiencing:
http://forums.mysql.com/read.php?24,57257
http://forum.percona.com/s/m/790/
I did some testing yesterday and this 1 sql statement successfully
queried
(in milliseconds) approximately 50,000 times before it took several
minutes
to query, which hung all the other processes on the database.
Because it
occurs successfully so many times, I know the query is good.
Is it possible to set a time limit on a single function in PHP?
E.g., when I
call mysql_query() and it takes 30 seconds, then quit processing that
function and continue on. I know I could set_time_limit() to a
specific
time, but that would cause a fatal error... and I want to be able
to catch
it.
Any thoughts on what direction I should go? Also, I'm going to do
some
research to see if a newer version of mysql has fixed this bug. We're
running 5.0.45.
Thanks,
~Philip
You could use ErrorException and catch that:
http://www.php.net/manual/en/class.errorexception.php
Or you could just set your own error handler:
http://www.php.net/manual/en/function.set-error-handler.php
Something I don't know if you've thought of that came to mind, though,
is the MySQL query cache. It's entirely likely that you have a query
that takes several minutes to run, then is stored in query cache for
the next 50,000 iterations of the query. Have you observed this same
behavior without the query cache enabled (it also looks like the bug
mentioned in the second link - the one that pertains to the 5.0.x
branch of mysql - has to do with an overly large query cache)? Based
on that post, I'd guess that your next action would be to disable the
query cache and determine from there if it's a slow query or actually
the bug in MySQL.
I didn't think you could catch fatal errors - isn't that why they're
fatal?
I will check into the query cache thing. However, the query that I'm
running isn't exactly the same each time. Each iteration has a
different ID value in the WHERE clause.
Thank you,
~Philip
