Re: [PERFORMANCE] work_mem vs temp files issue - Mailing list pgsql-performance

From Tom Lane
Subject Re: [PERFORMANCE] work_mem vs temp files issue
Date
Msg-id 10990.1263397358@sss.pgh.pa.us
Whole thread Raw
In response to Re: [PERFORMANCE] work_mem vs temp files issue  (Robert Haas <robertmhaas@gmail.com>)
Responses Re: [PERFORMANCE] work_mem vs temp files issue
List pgsql-performance
Robert Haas <robertmhaas@gmail.com> writes:
> I had an idea at one point of making explain show the planned and
> actual # of batches for each hash join.  I believe that "actual # of
> batches > 1" is isomorphic to "hash join went to disk".  The code is
> actually pretty easy; the hard part is figuring out what to do about
> the UI.  The choices seem to be:

> 1. Create a new EXPLAIN option just for this - what would we call it?
> 2. Think of some more, similar things and come up with a new EXPLAIN
> option covering all of them - what else would go along with?
> 3. Sandwhich it into an existing EXPLAIN option, most likely VERBOSE.
> 4. Display it by default.

Treat it the same as the Sort-node actual usage information.  We did not
add a special option when we added that.

            regards, tom lane

pgsql-performance by date:

Previous
From: Robert Haas
Date:
Subject: Re: [PERFORMANCE] work_mem vs temp files issue
Next
From: Eduardo Piombino
Date:
Subject: Re: a heavy duty operation on an "unused" table kills my server