2012/01/07 16:58, Heikki Linnakangas wrote:
On 07.01.2012 00:24, Robert Haas wrote:
It's been a while since I did any testing with LWLOCK_STATS defined,
so I thought it might be about time to do that again and see how
things look. Here's how they looked back in July:
http://archives.postgresql.org/pgsql-hackers/2011-07/msg01373.php
Interesting.
A couple of weeks ago I wrote a little patch that's similar to LWLOCK_STATS,
but it prints out % of wallclock time that is spent acquiring, releasing, or
waiting for a lock. I find that more useful than the counters.
Here's the patch, I hope it's useful to others. It uses timer_create() and
timer_settime(), so it probably won't work on all platforms, and requires
linking with -lrt.
I have just written up a systemtap script to observe
lock statistics.
It shows acquire counts, wait counts and
total waiting time for each lwlock every 5 seconds.
Screenshot here:
http://twitpic.com/83p2cz
Is this useful for pg developers?
--
Satoshi Nagayasu <sn...@uptime.jp>
Uptime Technologies, LLC. http://www.uptime.jp
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