Date: Sat, 12 May 2007 19:24:51 -0400 (EDT)
From: Greg Smith <gsmith@gregsmith.com>
To: pgsql-hackers@postgresql.org
Subject: Re: Performance monitoring
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On Sat, 12 May 2007, Joshua D. Drake wrote:

> One thing that doesn't seemed to be being looked at it is the cost of 
> logging.

If any of this executed at something like the query level, sure, that 
would be real important.  The majority of the logging I suggested here is 
of things that happen at checkpoint time.  The presumption is that the 
overhead of that is considerably greater than writing a log line or even 
five.

The least intensive event I would like to be loggable is when a new WAL 
segment is created and cleared, which is again a pretty small bit of log 
compared to the 16MB write.  I wouldn't mind seeing that exposed under 
pg_stats instead, just had more interesting things to statify first.

--
* Greg Smith gsmith@gregsmith.com http://www.gregsmith.com Baltimore, MD