Wow. That is a nice logging feature in 8.3! 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: Bill Moran [mailto:wmoran@xxxxxxxxxxxxxxxxxxxxxxx] Sent: Friday, November 09, 2007 2:08 PM To: Campbell, Lance Cc: pgsql-performance@xxxxxxxxxxxxxx Subject: Re: work_mem and shared_buffers On Fri, 9 Nov 2007 12:08:57 -0600 "Campbell, Lance" <lance@xxxxxxxx> wrote: > 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? 8.2 and older, it can be difficult to know, and I don't have a specific recommendation. 8.3 includes a parameter to log the usage of temporary files by Postgres. When a sort can't fit in the available memory, it uses a temp file, thus you could use this new feature to track when sorts don't fit in work_mem. -- Bill Moran Potential Technologies http://www.potentialtech.com ---------------------------(end of broadcast)--------------------------- TIP 9: In versions below 8.0, the planner will ignore your desire to choose an index scan if your joining column's datatypes do not match
