Bill Moran a écrit :
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.
I haven't use it in that context before, but perhaps inotify can be used
to catch postgresql usage of temp files. ( http://inotify.aiken.cz/ ,
http://inotify.aiken.cz/?section=incron&page=about&lang=en )
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.
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