[RndTbl] hung mysql transaction locks after a php runtime error?
trevor at tecnopolis.ca
Fri Jul 31 23:24:08 CDT 2020
On 2020-07-31 Adam Thompson wrote:
> I think what you need is ErrorException. See
> Basically it's a way to turn regular PHP errors into Exceptions so
> you can Catch them, and then you also get to have a Finally block
> where you can rollback unconditionally.
> The comments on that page are more valuable than the official
> documentation, as usual.
Yes, something like that would be ideal. I was glancing at it as a
possible solution before, but the bit about not being able to catch
some errors, like E_ERROR or E_PARSE, mean it likely won't help. Maybe
I'll do a test run to see exactly what error is produced by things like
calling an invalid fn, or calling with the wrong # of args.
Luckily programmer-stupidity mistakes like that are very rare in my
production code :-) However, they are common on my dev box. In the
end, if the mysql innodb lock timeout really works as I think it does
(rolling back that thread after 50s) then the repercussions aren't as
bad as I had feared. A locked-out user for 50s is possibly acceptable.
Locking all users out for 50s is not.
And I have that rollback to start every hit as Scott suggested, so that
should help too.
What I really require is something in the php-fpm engine that lets me
trigger a script to run after every cgi hit is done processing (whether
successful or crashed). In there I could put a connect/rollback.
Does anyone have any guess what sort of performance hit my site would
take if I turned off all of PHP's mysql connection persistence? Does
starting a new connection for each hit really take that many cycles?
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