Message-ID: <504e576d-984f-d73c-2694-8ee9624f8def@enterprisedb.com>
Date: Tue, 19 Oct 2021 15:25:52 +0200
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Subject: Re: Partial aggregates pushdown
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To: Alexander Pyhalov <a.pyhalov@postgrespro.ru>
Cc: pgsql-hackers@postgresql.org
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 <2486a6db3f068efb97c1277c23402e0d@postgrespro.ru>
From: Tomas Vondra <tomas.vondra@enterprisedb.com>
In-Reply-To: <2486a6db3f068efb97c1277c23402e0d@postgrespro.ru>
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On 10/19/21 08:56, Alexander Pyhalov wrote:
> Hi.
> 
> Tomas Vondra писал 2021-10-15 17:56:
>> As for the proposed approach, it's probably good enough for the first
>> version to restrict this to aggregates where the aggregate result is
>> sufficient, i.e. we don't need any new export/import procedures.
>>
>> But it's very unlikely we'd want to restrict it the way the patch does
>> it, i.e. based on aggregate name. That's both fragile (people can
>> create new aggregates with such name) and against the PostgreSQL
>> extensibility (people may implement custom aggregates, but won't be
>> able to benefit from this just because of name).
>>
>> So for v0 maybe, but I think there neeeds to be a way to relax this in
>> some way, for example we could add a new flag to pg_aggregate to mark
>> aggregates supporting this.
>>
> 
> Updated patch to mark aggregates as pushdown-safe in pg_aggregates.
> 
> So far have no solution for aggregates with internal aggtranstype.

Thanks. Please add it to the next CF, so that we don't lose track of it.

regards

-- 
Tomas Vondra
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