Re: Postgres consuming way too much memory???

[Bruce Momjian <pgman(at)candle(dot)pha(dot)pa(dot)us>]

Added to TODO:

>               o Fix memory leak from exceptions
>
>                http://archives.postgresql.org/pgsql-performance/2006-06/msg0$


---------------------------------------------------------------------------

Tom Lane wrote:
> "jody brownell" <jody(dot)brownell(at)Q1Labs(dot)com> writes:
> > 	BEGIN
> >           INSERT into attacker_target_link (attacker_id, target_id) values (p_attacker, v_target);
> >           v_returns_size := v_returns_size + 1;
> >           v_returns[v_returns_size] := v_target;
>           
> > 	EXCEPTION WHEN unique_violation THEN
> > 		-- do nothing... app cache may be out of date.
> > 	END;
> 
> Hmm.  There is a known problem that plpgsql leaks some memory when
> catching an exception:
> http://archives.postgresql.org/pgsql-hackers/2006-02/msg00885.php
> 
> So if your problem case involves a whole lot of duplicates then that
> could explain the initial bloat.  However, AFAIK that leakage is in
> a transaction-local memory context, so the space ought to be freed at
> transaction end.  And Linux's malloc does know about giving space back
> to the kernel (unlike some platforms).  So I'm not sure why you're
> seeing persistent bloat.
> 
> Can you rewrite the function to not use an EXCEPTION block (perhaps
> a separate SELECT probe for each row --- note this won't be reliable
> if there are concurrent processes making insertions)?  If so, does
> that fix the problem?
> 
> 			regards, tom lane
> 
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-- 
  Bruce Momjian   http://candle.pha.pa.us
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