| From: | Tobias Brox <tobixen(at)gmail(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Artur Zając <azajac(at)ang(dot)com(dot)pl>, pgsql-performance(at)postgresql(dot)org |
| Subject: | Re: Difference between explain analyze and real execution time |
| Date: | 2010-11-15 15:25:18 |
| Message-ID: | AANLkTikS9iNgDB651S4x7FZHRqo_GSQ_1dbjX+3RRYg_@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
[Tom Lane]
> EXPLAIN ANALYZE doesn't account for all of the runtime involved. In
> this case, I'd bet that session startup/shutdown is a big part of the
> difference.
The session startup/shutdown should be the same for the real SQL and
the broken SQL, shouldn't it?
[Artur Zając]
> time psql -c 'explain analyze SELECT te.idt FROM t_positions AS te
> JOIN t_st AS stm ON (te.idt=stm.idt AND 4=stm.idm) WHERE te.idtr IN
> (347186)'
Is this weidness only observed for this query? What happens with
other queries? "explain analyze select 1"? "explain analyze select *
from t_positions where idtr=347816"? plain select without "explain
analyze"? etc?
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Andy Colson | 2010-11-15 19:27:43 | Re: Running PostgreSQL as fast as possible no matter the consequences |
| Previous Message | Artur Zając | 2010-11-15 15:24:30 | Re: Difference between explain analyze and real execution time |