On Sat, Oct 13, 2012 at 11:34 PM, Satoshi Nagayasu <sn...@uptime.jp> wrote: > Hi, > > 2012/10/13 23:05, Satoshi Nagayasu wrote: >> Hi all, >> >> I have fixed my previous patch for pg_stat_lwlocks view, and >> as Josh commented, it now supports local and global (shared) >> statistics in the same system view. > > Sorry, I found my mistakes. New fixed one is attached to this mail.
Thanks for revising the patch. Here are the comments: The document needs to be updated. The patch caused the following compile warnings in my machine. pgstat.c:1357: warning: no previous prototype for 'pgstat_report_lwlockstat' postgres.c:3922: warning: implicit declaration of function 'pgstat_report_lwlockstat' pgstatfuncs.c:1854: warning: no previous prototype for 'pg_stat_reset_lwlocks' In my test, this patch caused the measurable performance overhead. I created the test database by pgbench -s10 and ran pgbench -c8 -j8 -T60 -S. Results are: [HEAD] number of transactions actually processed: 1401369 tps = 23351.375811 (including connections establishing) tps = 23355.900043 (excluding connections establishing) [PATCH] number of transactions actually processed: 1401369 tps = 23351.375811 (including connections establishing) tps = 23355.900043 (excluding connections establishing) So I think that tracking lwlock usage should be enabled only when trace_lwlocks is enabled, so that a user who is not interested in lwlock usage can avoid such performance overhead. As far as I read the patch, only lwlock usage by backends is collected. Why aren't the lwlock usages by autovacuum worker and auxiliary processes collected? Regards, -- Fujii Masao -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
