Hi,
On 04/04/12 19:21, Eliot Gable wrote:
I have a Perl daemon handling some events on a system which inserts or
updates rows in Postgres, and something is causing memory usage to
grow. I see the RSS memory size allocated to the Postgres connection
continual going up (slowly) and the RSS size allocated to the Perl
daemon also continually going up (slowly). The Perl daemon is using
DBIx to make insert and update queries to the Postgres DB.
I believe DBIx is more of a namespace than a specific module - do you
mean DBIx::Class or DBI perhaps? If the former, the IRC channel
#dbix-class on irc.perl.org tends to be very helpful in tracing problems
like this, particularly if you can provide a reproducible test case.
There is only one connection open between the Perl daemon and the
Postgres DB. That connection stays open until the daemon exits or is
killed. When the daemon is killed, the Postgres back end is terminated
and all of its memory is released.
Any suggestions on how to go about troubleshooting this would be
useful. Most specifically, I would like to know how to find out what
the Postgres process for that connection is doing with all that
memory. Is there a way I can see what the memory is allocated for?
Would running GDB on the Postgres process help? Is there any logging I
can turn on which might help shed some light on what's using the
memory? Anything in particular anyone knows about which I should look
for which might cause both Perl and Postgres memory usage to climb
continually?
On the Perl side, Devel::Size and possible Test::MemoryGrowth may be of
some use in tracing where the memory is going. Does the memory usage hit
a ceiling at any point, or does it carry on until all virtual memory is
exhausted? You could try running the postgres and perl daemons with
lower ulimit -m / ulimit -v settings if the increase in memory is too
slow to test this in a reasonable timeframe.
Other than that, maybe try looking for statement handles that aren't
closed or long-running transactions?
best regards,
Tom
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