| From: | Stephan Szabo <sszabo(at)megazone(dot)bigpanda(dot)com> |
|---|---|
| To: | Jon Lapham <lapham(at)jandr(dot)org> |
| Cc: | pgsql-general(at)postgresql(dot)org |
| Subject: | Re: EXPLAIN ANALYZE total runtime != walltime |
| Date: | 2004-08-26 02:10:33 |
| Message-ID: | 20040825190945.H6086@megazone.bigpanda.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-general |
On Wed, 25 Aug 2004, Jon Lapham wrote:
> I have been using the EXPLAIN ANALYZE command to debug some performance
> bottlenecks in my database. In doing so, I have found an oddity (to me
> anyway). The "19ms" total runtime reported below actually takes 25
> seconds on my computer (no other CPU intensive processes running). Is
> this normal for EXPLAIN ANALYZE to report a total runtime so vastly
> different from wall clock time?
>
> During the "explain ANALYZE delete from msgid;" the CPU is pegged at
> 100% for the postmaster process, and the HD light only flashes
> intermittently, so I do not think it is HD I/O.
>
> I tossed in a "EXPLAIN ANALYZE VERBOSE" at the end of this email, in
> case that helps anyone.
I think EXPLAIN ANALYZE time doesn't include after trigger time (for
example for foreign keys). Do any tables reference this one?
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Tom Lane | 2004-08-26 02:18:30 | Re: EXPLAIN ANALYZE total runtime != walltime |
| Previous Message | Greg Stark | 2004-08-26 01:16:44 | Re: Aggregate query for multiple records |