work-mem how do I identify the proper size

["Campbell, Lance" <lance(at)uiuc(dot)edu>]

If I set work-mem at a particular amount of memory how do I answer the following questions:

 

1)       How many of my queries were able to run inside the memory I allocated for work-mem?

2)       How many of my queries had to run from disk because work-mem was not set high enough?

3)       If a query had to go to disk in order to be sorted or completed is there a way to identify how much memory it would have taken in order to run the query from memory?

 

Thanks for all of your help,

 

Lance Campbell

Project Manager/Software Architect

Web Services at Public Affairs

University of Illinois

217.333.0382

http://webservices.uiuc.edu