public inbox for [email protected]  

help / color / mirror / Atom feed
From: Andres Freund <[email protected]>
To: Tomas Vondra <[email protected]>
Cc: Peter Geoghegan <[email protected]>
Cc: Nazir Bilal Yavuz <[email protected]>
Cc: Thomas Munro <[email protected]>
Cc: Robert Haas <[email protected]>
Cc: Melanie Plageman <[email protected]>
Cc: PostgreSQL Hackers <[email protected]>
Cc: Georgios <[email protected]>
Cc: Konstantin Knizhnik <[email protected]>
Cc: Dilip Kumar <[email protected]>
Subject: Re: index prefetching
Date: Fri, 8 Aug 2025 19:47:13 -0400
Message-ID: <xhe4l63oxs36sunvqbf3bzlzrondjyhumm7ywt4arkxu622f52@yriy7rejf5g2> (raw)
In-Reply-To: <[email protected]>
References: <[email protected]>
	<[email protected]>
	<CAH2-WzmER9kc4OtmkDh+h51QV=v6Yc5BGsJikwJHtucf1C1HWw@mail.gmail.com>
	<[email protected]>
	<CAH2-Wz=0enySZ5g0k0BLY3tHRs=wyG=7yXDYP=Abt=6GM=7XkQ@mail.gmail.com>
	<[email protected]>
	<CAH2-WzkX2fwtiNOX4RrBR8=XKta999NM_5+ghTUnwUBkeyfcHQ@mail.gmail.com>
	<[email protected]>
	<CAH2-WzkPh+L2u8_4jG=NgGgzFNqW7ZZhSxGb6mJR=2YdouL1_Q@mail.gmail.com>
	<[email protected]>

Hi,

On 2025-08-06 16:12:53 +0200, Tomas Vondra wrote:
> That's quite possible. What concerns me about using tables like pgbench
> accounts table is reproducibility - initially it's correlated, and then
> it gets "randomized" by the workload. But maybe the exact pattern
> depends on the workload - how many clients, how long, how it correlates
> with vacuum, etc. Reproducing the dataset might be quite tricky.
> 
> That's why I prefer using "reproducible" data sets. I think the data
> sets with "fuzz" seem like a pretty good model. I plan to experiment
> with adding some duplicate values / runs, possibly with two "levels" of
> randomness (global for all runs, and smaller local perturbations).
> [...]
> Yeah, cases like that are interesting. I plan to do some randomized
> testing, exploring "strange" combinations of parameters, looking for
> weird behaviors like that.

I'm just catching up: Isn't it a bit early to focus this much on testing? ISMT
that the patchsets for both approaches currently have some known architectural
issues and that addressing them seems likely to change their performance
characteristics.

Greetings,

Andres Freund





view thread (348+ 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: index prefetching
  In-Reply-To: <xhe4l63oxs36sunvqbf3bzlzrondjyhumm7ywt4arkxu622f52@yriy7rejf5g2>

* 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