Re: sort_mem statistics ...

On Wed, 26 Oct 2005, Jim C. Nasby wrote:

> On Tue, Oct 18, 2005 at 06:15:02PM -0400, Tom Lane wrote:
>> "Marc G. Fournier" <scrappy@postgresql.org> writes:
>>> do we maintain anything anywhere for this?  mainly, some way of
>>> determining # of 'sorts to disk' vs 'sort in memory', to determine whether
>>> or not sort_mem is set to a good value?
>>
>> As of 8.1 you could turn on trace_sort to collect some data about this.
>
> While trace_sort is good, it doesn't really help for monitoring. What I
> would find useful would be statistics along the lines of:
>
> How many sorts have occured?
> How many spilled to disk?
> What's the largest amount of memory used by an in-memory sort?
> What's the largest amount of memory used by an on-disk sort?

Actually, I'd like to see largest/smallest and average in this ... but if 
all is being logged to syslog, I can easily determine those #s with a perl 
script ..

----
Marc G. Fournier           Hub.Org Networking Services (http://www.hub.org)
Email: scrappy@hub.org           Yahoo!: yscrappy              ICQ: 7615664