public inbox for [email protected]  

help / color / mirror / Atom feed

From: wenhui qiu <[email protected]>
To: Frédéric Yhuel <[email protected]>
Cc: Nathan Bossart <[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: Wed, 6 Nov 2024 20:51:07 +0800
Message-ID: <CAGjGUALGtQ8MoshY6tEUPiAOjWNefBzq61gZ_5Dx-Uai1cC39Q@mail.gmail.com> (raw)
In-Reply-To: <[email protected]>
References: <CA+Tgmoa9FzNLNtD-PYptJP1ApV=a57RwqOVypb0gL5uLzLtCFQ@mail.gmail.com>
	<CAApHDvo8DWyt4CWhF=NPeRstz_78SteEuuNDfYO7cjp=7YTK4g@mail.gmail.com>
	<CA+TgmoaCQ_GCwn3V8uXc+60oSJivY6ouiAqe81Z3h1kT6zMMYQ@mail.gmail.com>
	<20240507211702.GA2720371@nathanxps13>
	<[email protected]>
	<CA+TgmoYF3HqEUArbsqtCtP7YMJ62G3U8W1mSmZFZoCK8uBSi9g@mail.gmail.com>
	<[email protected]>
	<CA+TgmoaER+O40PA_CB8eSKm7KT37wDT+-y_mnsWXb9-Keivu1Q@mail.gmail.com>
	<ZnD509Q1jROYKhz_@nathan>
	<[email protected]>
	<ZrPprRLBzi1YUBLn@nathan>
	<[email protected]>

Hi frederic.yhuel

> Thank you. FWIW, I would prefer a sub-linear growth, so maybe something
> like this

>   vacthresh = Min(vac_base_thresh + vac_scale_factor * reltuples,
>   vac_base_thresh + vac_scale_factor * pow(reltuples, 0.7) * 100);

>   This would give :

>   * 386M (instead of 5.1 billion currently) for a 25.6 billion tuples
table ;
>   * 77M for a 2.56 billion tuples table (Robert's example) ;
>   * 15M (instead of 51M currently) for a 256M tuples table ;
>   * 3M (instead of 5M currently) for a 25.6M tuples table.
> The other advantage is that you don't need another GUC.
Argee ,We just need to change the calculation formula，But I prefer this
formula because it calculates a smoother value.

vacthresh =  (float4) fmin(vac_base_thresh + vac_scale_factor *
reltuples,vac_base_thresh
+ vac_scale_factor * log2(reltuples) * 10000);
or
vacthresh = (float4) fmin(vac_base_thresh + (vac_scale_factor * reltuples)
, sqrt(1000.0 * reltuples));

Frédéric Yhuel <[email protected]> 于2024年8月12日周一 21:41写道：

>
>
> On 8/7/24 23:39, Nathan Bossart wrote:
> > I've attached a new patch to show roughly what I think this new GUC
> should
> > look like.  I'm hoping this sparks more discussion, if nothing else.
> >
>
> Thank you. FWIW, I would prefer a sub-linear growth, so maybe something
> like this:
>
> vacthresh = Min(vac_base_thresh + vac_scale_factor * reltuples,
> vac_base_thresh + vac_scale_factor * pow(reltuples, 0.7) * 100);
>
> This would give :
>
> * 386M (instead of 5.1 billion currently) for a 25.6 billion tuples table ;
> * 77M for a 2.56 billion tuples table (Robert's example) ;
> * 15M (instead of 51M currently) for a 256M tuples table ;
> * 3M (instead of 5M currently) for a 25.6M tuples table.
>
> The other advantage is that you don't need another GUC.
>
> > On Tue, Jun 18, 2024 at 12:36:42PM +0200, Frédéric Yhuel wrote:
> >> By the way, I wonder if there were any off-list discussions after
> Robert's
> >> conference at PGConf.dev (and I'm waiting for the video of the conf).
> >
> > I don't recall any discussions about this idea, but Robert did briefly
> > mention it in his talk [0].
> >
> > [0] https://www.youtube.com/watch?v=RfTD-Twpvac
> >
>
> Very interesting, thanks!
>
>
>

view thread (16+ messages)  latest in thread

reply

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Reply to all the recipients using the --to and --cc options:
  reply via email

  To: [email protected]
  Cc: [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected], [email protected]
  Subject: Re: New GUC autovacuum_max_threshold ?
  In-Reply-To: <CAGjGUALGtQ8MoshY6tEUPiAOjWNefBzq61gZ_5Dx-Uai1cC39Q@mail.gmail.com>

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

This inbox is served by agora; see mirroring instructions
for how to clone and mirror all data and code used for this inbox