Re: work_mem and shared_buffers

[Cédric Villemain <cedric(dot)villemain(at)dalibo(dot)com>]

Bill Moran a écrit :
> On Fri, 9 Nov 2007 12:08:57 -0600
> "Campbell, Lance" <lance(at)uiuc(dot)edu> 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.
>
>