| From: | "Joshua D(dot) Drake" <jd(at)commandprompt(dot)com> |
|---|---|
| To: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Cc: | Sriram Dandapani <sdandapani(at)counterpane(dot)com>, "Pgsql-Performance (E-mail)" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: select max(column) from parent table very slow |
| Date: | 2006-08-25 05:16:43 |
| Message-ID: | 44EE87BB.4050104@commandprompt.com |
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| Thread: | |
| Lists: | pgsql-performance |
Tom Lane wrote:
> "Joshua D. Drake" <jd(at)commandprompt(dot)com> writes:
>> Sriram Dandapani wrote:
>>> Parent table has a column say column1 which is indexed (parent table and
>>> all child tables are indexed on that column)
>
>> In older versions of postgresql that would scan the whole table. In 8.1
>> and above it doesn't. However, I am guess that since this is a
>> partitioned table the planner isn't smart enough to just perform the
>> query on each child and a max on the set that is returned.
>
> It is not. Feel free to submit a patch for planagg.c ...
I think my patch to pgbench may have set your expectations of me a bit
high ;)...
Joshua D. Drake
>
> regards, tom lane
>
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