Re: Partition : Append node over a single SeqScan

From: Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com>
To: Ashutosh Bapat <ashutosh(dot)bapat(at)enterprisedb(dot)com>
Cc: pgsql-hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: Partition : Append node over a single SeqScan
Date: 2017-07-05 12:52:29
Message-ID: CAE9k0Pk-=B8YYTQcXY7RB0o9iirThZfncEsT-jbLXgbmtHohYw@mail.gmail.com
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Hi,

On Wed, Jul 5, 2017 at 3:58 PM, Ashutosh Bapat
<ashutosh(dot)bapat(at)enterprisedb(dot)com> wrote:
> On Wed, Jul 5, 2017 at 3:48 PM, Ashutosh Sharma <ashu(dot)coek88(at)gmail(dot)com> wrote:
>> Hi All,
>>
>> Today while exploring a bit on Range table partitioning, I could see
>> that even if scan is performed on a single partition, the plan node
>> has Append node in it. Isn't it a bug?
>
> No. See following comment from create_append_plan()
> 1045 /*
> 1046 * XXX ideally, if there's just one child, we'd not bother to
> generate an
> 1047 * Append node but just return the single child. At the
> moment this does
> 1048 * not work because the varno of the child scan plan won't match the
> 1049 * parent-rel Vars it'll be asked to emit.
> 1050 */
>

Thanks for the information.

--
With Regards,
Ashutosh Sharma
EnterpriseDB:http://www.enterprisedb.com

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