| From: | Greg Stark <stark(at)mit(dot)edu> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org>, Joel Jacobson <joel(at)trustly(dot)com> |
| Subject: | Re: pg_stat_activity.waiting_start |
| Date: | 2016-12-27 17:17:36 |
| Message-ID: | CAM-w4HOR4Jo6ecj12t3ae9Kj7kFg9EFAcvc3X1jNY6c0QeF+iw@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-hackers |
On Dec 24, 2016 5:44 PM, "Tom Lane" <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
I think we'd need at least an order of
magnitude cheaper to consider putting timing calls into spinlock or lwlock
paths, and that's just not available at all, let alone portably.
For spinlocks we could conceivably just bite the bullet and use a raw rdtsc
or the equivalent for other platforms. It might be pretty easy to
distinguish sane numbers from numbers that result after a process
reschedule and we could just discard data when that happens (or count
occurrences).
That may possibly work for spinlocks but it won't work for anything heavier
where process reschedules are routine.
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Fabien COELHO | 2016-12-27 17:51:44 | Re: BUG: pg_stat_statements query normalization issues with combined queries |
| Previous Message | Fabien COELHO | 2016-12-27 17:16:45 | Re: BUG: pg_stat_statements query normalization issues with combined queries |