Re: pg_stat_lwlocks view - lwlocks statistics

On 6/25/12 1:29 PM, Satoshi Nagayasu wrote:
> (1) Performance
> 
>   I've measured LWLock performance both with and without the patch,
>   and confirmed that this patch does not affect the LWLock perfomance
>   at all.

This would be my main concern with this patch; it's hard for me to
imagine that it has no performance impact *at all*, since trace_lwlocks
has quite a noticable one in my experience.  However, the answer to that
is to submit the patch and let people test.

I will remark that it would be far more useful to me if we could also
track lwlocks per session.  Overall counts are somewhat useful, but more
granular counts are even more useful.  What period of time does the
table cover?  Since last reset?

-- 
Josh Berkus
PostgreSQL Experts Inc.
http://pgexperts.com