Thread

1. Backend memory growing too much

   ohp@pyrenet.fr — 2007-07-17T13:19:29Z

   Hi everyone,
   
   I've been using sqlgrey for some time now and I'm very surprised by the
   memory taken by the backends to which sqlgrey is connected.
   
   look at process 4111 and 28108 . They roughly take twice the space the
   other backend take.
   
   Could there be a memory leak?
   
   I don't know much about DBI/DBD but I know sqlgrey uses a lot of
   prepare/prepare_cached statements.
   
   What could cause?
   
   shared_buffer is 400MB here.
   
   TIA
   
   -- 
   Olivier PRENANT        	        Tel: +33-5-61-50-97-00 (Work)
   15, Chemin des Monges                +33-5-61-50-97-01 (Fax)
   31190 AUTERIVE                       +33-6-07-63-80-64 (GSM)
   FRANCE                          Email: ohp@pyrenet.fr
   ------------------------------------------------------------------------------
   Make your life a dream, make your dream a reality. (St Exupery)

2. Re: Backend memory growing too much

   Tom Lane <tgl@sss.pgh.pa.us> — 2007-07-17T15:13:38Z

   ohp@pyrenet.fr writes:
   > I don't know much about DBI/DBD but I know sqlgrey uses a lot of
   > prepare/prepare_cached statements.
   
   Well, those aren't exactly free.
   
   Possibly you could learn something about it by attaching to one of
   these backends with gdb and executing
   
   	call MemoryContextStats(TopMemoryContext)
   
   This will dump a memory map to stderr.
   
   			regards, tom lane
   
   

3. Re: Backend memory growing too much

   Andrew Dunstan <andrew@dunslane.net> — 2007-07-17T15:30:43Z

   
   ohp@pyrenet.fr wrote:
   >
   > I don't know much about DBI/DBD but I know sqlgrey uses a lot of
   > prepare/prepare_cached statements.
   >
   >   
   
   You can inhibit DBD::Pg from using server side prepares  if you need to, 
   by executing:
   
     $dbh->{pg_server_prepare} = 0;
   
   (as documented in the excellent DBD::Pg docs).
   
   cheers
   
   andrew
   
   

4. Re: Backend memory growing too much

   ohp@pyrenet.fr — 2007-07-21T07:40:31Z

   Hi Andrew
   On Tue, 17 Jul 2007, Andrew Dunstan wrote:
   
   > Date: Tue, 17 Jul 2007 11:30:43 -0400
   > From: Andrew Dunstan <andrew@dunslane.net>
   > To: ohp@pyrenet.fr
   > Cc: pgsql-hackers list <pgsql-hackers@postgresql.org>
   > Subject: Re: [HACKERS] Backend memory growing too much
   >
   >
   >
   > ohp@pyrenet.fr wrote:
   > >
   > > I don't know much about DBI/DBD but I know sqlgrey uses a lot of
   > > prepare/prepare_cached statements.
   > >
   > >
   >
   > You can inhibit DBD::Pg from using server side prepares  if you need to,
   > by executing:
   >
   >   $dbh->{pg_server_prepare} = 0;
   >
   > (as documented in the excellent DBD::Pg docs).
   >
   > cheers
   >
   > andrew
   >
   Thanks! That made the trick!
   I assume this is because sqlgrey prepares statements (always the same) and
   neither finish them.
   
   Best regards
   -- 
   Olivier PRENANT        	        Tel: +33-5-61-50-97-00 (Work)
   15, Chemin des Monges                +33-5-61-50-97-01 (Fax)
   31190 AUTERIVE                       +33-6-07-63-80-64 (GSM)
   FRANCE                          Email: ohp@pyrenet.fr
   ------------------------------------------------------------------------------
   Make your life a dream, make your dream a reality. (St Exupery)