Re: OOM on large SELECT

On Thu, 2009-09-17 at 19:03 +0200, Angelo Nicolosi wrote:
> Sorry for the delay of this answer but i was trying to figure out.
> However I saw that the memory that the postgres is using is getting
> larger step by step.
> So it doesn't free it.

If the memory is allocated using palloc() and not freed even after the
query finishes, then you must be using a wrong memory context.

> After the third query it is already full and one of the thread of the
> postgres is killed from the OOM.
> When the process is killed the program usually is going to call again
> a stored function.
> By the way the info that you required me are:
>
>
> postgres (PostgreSQL) 8.4.0
> Linux kernel 2.6.18 64bits
>
>
> For the memory settings I have to contact the system admin because i
> don't have the rights, on that machines, to read the configurations
> file.

do

show work_mem;

from psql;

to see all conf params, do

show all;

> Thank you again to all for your help.
> Cheers,
> Angelo.
>
> > Date: Wed, 16 Sep 2009 09:30:59 -0700
> > From: pierce(at)hogranch(dot)com
> > To: amenuor(at)hotmail(dot)com
> > CC: pgsql-jdbc(at)postgresql(dot)org
> > Subject: Re: [JDBC] OOM on large SELECT
> >
> > Angelo Nicolosi wrote:
> > > It's possible that the problem is in my C code but every time that
> I'm
> > > allocating memory, using always the palloc() function, I'm always
> > > calling the pfree().
> > > There is some way to analyze the code meanwhile is working inside
> the
> > > Postgre server (something like valgrind)?
> > > However the command free -m on my machine outputs:
> > >
> > > total used free shared buffers cached
> > > Mem: 2010 664 1345 0 157 383
> > > -/+ buffers/cache: 123 1886
> > > Swap: 16386 41 16345
> > >
> > > I think that the swap is enough.
> > > Could you give me some tips about how can I see where is the
> problem?
> > > Thank you for your help!
> >
> > do you know what query you were making when you ran out of memory?
> it
> > -appears- it was a postgres server process that was OOM'd.
> >
> > what OS and version are you on (OOM seems to imply its likely
> linux,
> > since no other OS I'm familiar with would randomly kill processes
> like
> > that), what version postgres, etc ?
> >
> > also, what are the various memory settings in your postgresql.conf
> > (shared_buffers, work_mem, etc)
> >
> >
>
>
>
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