How do you know when you should up the value of work_mem? Just play with the number. Is there a query I could do that would tell me if PostgreSql is performing SQL that could use more memory for sorting? Thanks, Lance Campbell Project Manager/Software Architect Web Services at Public Affairs University of Illinois 217.333.0382 http://webservices.uiuc.edu -----Original Message----- From: Heikki Linnakangas [mailto:hlinnaka@xxxxxxxxx] On Behalf Of Heikki Linnakangas Sent: Friday, November 09, 2007 11:57 AM To: Campbell, Lance Cc: pgsql-performance@xxxxxxxxxxxxxx Subject: Re: work_mem and shared_buffers Campbell, Lance wrote: > Does the amount of memory allocate to work_mem get subtracted from > shared_buffers? > > Example: > > If work_mem is 1M and there are 10 connections and shared_buffers is > 100M then would the total be 90 M left for shared_buffers? > > Or does the amount of memory allocated for work_mem have nothing to do > with shared_buffers? No, they're completely separate. Note that a connection can use more than work_mem of memory. For example, if you run a query with multiple Sort or hash-nodes, each such node allocates up to work_mem of memory. -- Heikki Linnakangas EnterpriseDB http://www.enterprisedb.com ---------------------------(end of broadcast)--------------------------- TIP 4: Have you searched our list archives? http://archives.postgresql.org
