Horton

Re: document the need to analyze partitioned tables

Laurenz Albe <laurenz.albe@cybertec.at>

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From: Laurenz Albe <laurenz.albe@cybertec.at>
To: Bruce Momjian <bruce@momjian.us>
Cc: David Rowley <dgrowleyml@gmail.com>, Justin Pryzby <pryzby@telsasoft.com>, Nathan Bossart <nathandbossart@gmail.com>, Tomas Vondra <tomas.vondra@enterprisedb.com>, Robert Haas <robertmhaas@gmail.com>, Álvaro Herrera <alvherre@alvh.no-ip.org>, yuzuko <yuzukohosoya@gmail.com>, pgsql-hackers@postgresql.org
Date: 2023-09-29T22:39:43Z
Lists: pgsql-hackers 
On Fri, 2023-09-29 at 18:08 -0400, Bruce Momjian wrote:
> On Wed, Sep  6, 2023 at 05:53:56AM +0200, Laurenz Albe wrote:
> > > We may have different mental models here. This relates to the part
> > > that I wasn't keen on in your patch, i.e:
> > > 
> > > +    The partitions of a partitioned table are normal tables and get processed
> > > +    by autovacuum
> > > 
> > > While I agree that the majority of partitions are likely to be
> > > relkind='r', which you might ordinarily consider a "normal table", you
> > > just might change your mind when you try to INSERT or UPDATE records
> > > that would violate the partition constraint. Some partitions might
> > > also be themselves partitioned tables and others might be foreign
> > > tables. That does not really matter much when it comes to what
> > > autovacuum does or does not do, but I'm not really keen to imply in
> > > our documents that partitions are "normal tables".
> > 
> > Agreed, there are differences between partitions and normal tables.
> > And this is not the place in the documentation where we would like to
> > get into detail about the differences.
> > 
> > Attached is the next version of my patch.
> 
> I adjusted your patch to be shorter and clearer, patch attached.  I am
> planning to apply this back to PG 11.

Thanks for looking at this.

I am mostly fine with your version, but it does not directly state that
autovacuum does not process partitioned tables.  I think this should be
clarified in the beginning.

Yours,
Laurenz Albe

Commits

  1. doc: Fix typo in ANALYZE documentation

  2. Document autoanalyze limitations for partitioned tables

  3. Revert analyze support for partitioned tables

  4. Describe (auto-)analyze behavior for partitioned tables