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help / color / mirror / Atom feedFrom: Nathan Bossart <[email protected]>
To: wenhui qiu <[email protected]>
Cc: Frédéric Yhuel <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Imseih (AWS), Sami <[email protected]>
Cc: David Rowley <[email protected]>
Cc: Joe Conway <[email protected]>
Cc: Michael Banck <[email protected]>
Cc: Laurenz Albe <[email protected]>
Cc: Melanie Plageman <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Subject: Re: New GUC autovacuum_max_threshold ?
Date: Sat, 9 Nov 2024 09:59:42 -0600
Message-ID: <Zy-G7u43r1siVkQ6@nathan> (raw)
In-Reply-To: <CAGjGUALGwH9LJUxe+ZbjnW_Cg4B4qyFrXFv+oWYCYnLcwggBJQ@mail.gmail.com>
References: <CA+TgmoYF3HqEUArbsqtCtP7YMJ62G3U8W1mSmZFZoCK8uBSi9g@mail.gmail.com>
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On Sat, Nov 09, 2024 at 10:08:51PM +0800, wenhui qiu wrote:
> Sorry ,I forgot to explain the reason in my last email,In fact, I
> submitted the patch to the community,([email protected]) told me
> there has a same idea ,so ,
> Let me explain those two formulas here,about ( vacthresh = (float4)
> fmin(vac_base_thresh + (vac_scale_factor * reltuples), sqrt(1000.0 *
> reltuples)); A few days ago, I was looking at the sql server
> documentation and found that sql server has optimized the algorithm related
> to updating statistics in the 2016 ,version,I think we can also learn from
> the implementation method of sql server to optimize the problem of
> automatic vacuum triggered by large tables,The Document link(
> https://learn.microsoft.com/en-us/sql/relational-databases/statistics/statistics?view=sql-server-ver...
> ),about ( vacthresh = (float4) fmin(vac_base_thresh + vac_scale_factor *
> reltuples,vac_base_thresh+ vac_scale_factor * log2(reltuples) * 10000);)I
> came to the conclusion by trying to draw a function graph,I personally
> think it is a smooth formula
AFAICT the main advantage of these formulas is that you don't need another
GUC, but they also makes the existing ones more difficult to configure.
Plus, there's no way to go back to the existing behavior.
--
nathan
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Subject: Re: New GUC autovacuum_max_threshold ?
In-Reply-To: <Zy-G7u43r1siVkQ6@nathan>
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