| Lists: | pgsql-hackers |
|---|
| From: | Rudyar <rudyar(dot)cortes(at)gmail(dot)com> |
|---|---|
| To: | pgsql-hackers(at)postgresql(dot)org |
| Subject: | explain analyze query execution time |
| Date: | 2011-11-22 01:33:33 |
| Message-ID: | 4ECAFBED.4090208@gmail.com |
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| Lists: | pgsql-hackers |
Hello,
I try to get the execution time of a query workload. I try using explain
analyze but this time is allways higher than
the execution time of a query across a client like pgadmin3
what is the reason about that difference?
| From: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
|---|---|
| To: | Rudyar <rudyar(dot)cortes(at)gmail(dot)com>, pgsql-hackers <pgsql-hackers(at)postgresql(dot)org> |
| Subject: | Re: explain analyze query execution time |
| Date: | 2011-11-22 04:20:18 |
| Message-ID: | CAMkU=1wFOAL726P9e18i1pZePu1QE++JfdFGSD1p2_e8eEAfHw@mail.gmail.com |
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| Lists: | pgsql-hackers |
On 11/21/11, Rudyar <rudyar(dot)cortes(at)gmail(dot)com> wrote:
> Hello,
>
> I try to get the execution time of a query workload. I try using explain
> analyze but this time is allways higher than
> the execution time of a query across a client like pgadmin3
>
> what is the reason about that difference?
Analyze has to do a lot of gettimeofday calls and other bookkeeping,
and that takes time. If the data queried is all in memory, this
analyze overhead can be far more than the query itself.
Jeff