Re: sequential scan on child partition tables - Mailing list pgsql-performance

From Anj Adu
Subject Re: sequential scan on child partition tables
Date
Msg-id f2fd819a0910180824u4846a214w6a0a43f75415b72@mail.gmail.com
Whole thread Raw
In response to Re: sequential scan on child partition tables  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-performance
The actual data returned is a tiny fraction of the total table volume.

Is there a way to force an index scan on the partitions in a
guaranteed manner without resorting to re-writing queries with the
union all on partitions.

Thank you

Sriram

On Wed, Oct 14, 2009 at 10:15 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
> Anj Adu <fotographs@gmail.com> writes:
>> This query is doing a sequential scan on the child partitions even
>> though indexes on all constrained columns are present
>
> It looks to me like it's doing exactly what it is supposed to, ie,
> indexscan on the partitions where it would help and seqscans on the
> partitions where it wouldn't.  Indexscan is not better than seqscan
> for retrieving all or most of a table.
>
>                        regards, tom lane
>

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