| From: | Andres Freund <andres(at)anarazel(dot)de> |
|---|---|
| To: | Alvaro Herrera <alvherre(at)alvh(dot)no-ip(dot)org> |
| Cc: | Kyotaro HORIGUCHI <horiguchi(dot)kyotaro(at)lab(dot)ntt(dot)co(dot)jp>, yuzuko <yuzukohosoya(at)gmail(dot)com>, Tomas Vondra <tomas(dot)vondra(at)enterprisedb(dot)com>, David Steele <david(at)pgmasters(dot)net>, Kyotaro Horiguchi <horikyota(dot)ntt(at)gmail(dot)com>, Justin Pryzby <pryzby(at)telsasoft(dot)com>, Daniel Gustafsson <daniel(at)yesql(dot)se>, Amit Langote <amitlangote09(at)gmail(dot)com>, Masahiko Sawada <masahiko(dot)sawada(at)2ndquadrant(dot)com>, Laurenz Albe <laurenz(dot)albe(at)cybertec(dot)at>, PostgreSQL Hackers <pgsql-hackers(at)lists(dot)postgresql(dot)org>, Greg Stark <stark(at)mit(dot)edu> |
| Subject: | Re: Autovacuum on partitioned table (autoanalyze) |
| Date: | 2021-08-09 22:25:49 |
| Message-ID: | 20210809222549.jkfg4bh5xhww4teb@alap3.anarazel.de |
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| Lists: | pgsql-hackers |
Hi,
On 2021-08-09 16:02:33 -0400, Alvaro Herrera wrote:
> On 2021-Jul-27, Andres Freund wrote:
>
> > Isn't this going to create a *lot* of redundant sampling? Especially if you
> > have any sort of nested partition tree. In the most absurd case a partition
> > with n parents will get sampled n times, solely due to changes to itself.
>
> It seems to me that you're barking up the wrong tree on this point.
> This problem you describe is not something that was caused by this
> patch; ANALYZE has always worked like this. We have discussed the idea
> of avoiding redundant sampling, but it's clear that it is not a simple
> problem, and solving it was not in scope for this patch.
I don't agree. There's a difference between this happening after a manual
ANALYZE on partition roots, and this continuously happening in production
workloads due to auto-analyzes...
Greetings,
Andres Freund
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