Re: Draft LIMIT pushdown to Append and MergeAppend patch

From: Andy Fan <zhihui(dot)fan1213(at)gmail(dot)com>
To: Michał Kłeczek <michal(at)kleczek(dot)org>
Cc: PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>
Subject: Re: Draft LIMIT pushdown to Append and MergeAppend patch
Date: 2023-10-08 01:33:50
Message-ID: CAKU4AWpSHwfr1PNk30hxjD75V+nTraeApJ-SHx7K8EeSpbAMBA@mail.gmail.com
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On Sun, Oct 8, 2023 at 5:04 AM Michał Kłeczek <michal(at)kleczek(dot)org> wrote:

> Hi All,
>
> Attached is a second version of the patch.
>
> The goal is to:
> 1. Apply LIMIT as early as possible - especially to apply LIMIT in
> partition scans
>

For the patches for performance improvement, it is better to provide
an example to show how much benefits we can get. As for this case,
I'm doubtful it can work as an improvement.

2. Enable LIMIT pushdown for FDW partitions.
>

The same as above, some testing is helpful.

--
Best Regards
Andy Fan

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