On 12/28/16 11:25 AM, Tom Lane wrote:
The idea of just capturing the wait start for heavyweight locks, and not other lock types, still seems superior to any of the alternatives that have been suggested ...
Is some kind of alarm a viable option for the others? If setting the alarm is cheap, you could just set one for say 5ms when you have to wait on a lock. If setting one is too expensive perhaps one could be set at transaction start that looks at a global (and the global would be set when a wait started). Obviously that means there's inaccuracy to the true time spent waiting, but I think that's certainly fine for pg_stat_activity. Most importantly, it would mean that if something has gone horribly wrong you'd at least have some kind of relatively accurate duration to work from.
-- Jim Nasby, Data Architect, Blue Treble Consulting, Austin TX Experts in Analytics, Data Architecture and PostgreSQL Data in Trouble? Get it in Treble! http://BlueTreble.com 855-TREBLE2 (855-873-2532) -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers
