Re: An issue in remote query optimization

From: Etsuro Fujita <fujita(dot)etsuro(at)lab(dot)ntt(dot)co(dot)jp>
To: Abbas Butt <abbas(dot)butt(at)enterprisedb(dot)com>, PostgreSQL Hackers <pgsql-hackers(at)postgresql(dot)org>
Subject: Re: An issue in remote query optimization
Date: 2017-01-31 10:25:15
Message-ID: ee1b3b18-95b2-94b5-9c12-d8596fd216a9@lab.ntt.co.jp
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On 2017/01/31 18:24, Abbas Butt wrote:
> Postgres_fdw optimizes remote queries by pushing down the where clause.
> This feature does not work consistently when the query is executed from
> within a pl/pgsql function. The optimization works when the function
> executes the query for the first 5 times, and fails afterwards.

> I understand that this is because PostgreSQL starts using generic plan
> with pulled up where clause after the 5th invocation hoping that it
> would be faster since we have skiped planning the query on each
> invocation, but in this case this decision is causing the query to slow
> down.
>
> How should we fix this problem?

ANALYZE for the foreign table doesn't work?

Best regards,
Etsuro Fujita

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