More info in explain analyze

From: Jeff <threshar(at)torgo(dot)978(dot)org>
To: pgsql-performance(at)postgresql(dot)org
Subject: More info in explain analyze
Date: 2003-10-28 14:05:15
Message-ID: 20031028090515.278c8342.threshar@torgo.978.org
Views: Raw Message | Whole Thread | Download mbox | Resend email
Thread:
Lists: pgsql-performance

This has probably been asked before, but I'll re-ask to spark debate on it again.

Is there any good reason to not have explain analyze also include information if temporary files will be required on sorts, hashes, etc. during the processing of a query. [Idea being setting your sort_mem won't be purely anecdotal]... maybe include how much space it needed in temp files?
something along the lines of:

Sort (Cost=1..10) (Actual=1..1000) (Temp Files=5MB)

Seeing that and looking at your current sort_mem and seeing it is 4MB you'll have the info you need to get a nice boost by avoiding that spill at a low cost.

--
Jeff Trout <jeff(at)jefftrout(dot)com>
http://www.jefftrout.com/
http://www.stuarthamm.net/

Browse pgsql-performance by date

  From Date Subject
Next Message Jeff 2003-10-28 14:16:45 Adding foreign key performance
Previous Message Manfred Koizar 2003-10-28 10:59:36 Re: Guesses on what this NestLoop is for?