Re: Partitioned index can be not dumped

Alvaro Herrera <alvherre@alvh.no-ip.org>

From: Álvaro Herrera <alvherre@alvh.no-ip.org>
To: Alexander Pyhalov <a.pyhalov@postgrespro.ru>
Cc: Pgsql Hackers <pgsql-hackers@postgresql.org>
Date: 2021-06-30T18:54:09Z
Lists: pgsql-hackers

Attachments

On 2021-Jun-30, Alexander Pyhalov wrote:

> I've seen the following effect on PostgreSQL 14 stable branch.
> Index, created on partitioned table, disappears from pg_dump or psql \d
> output.
> This seems to begin after analyze. Partitoned relation relhasindex pg_class
> field suddenly becomes false.

Yeah, that seems correct.

I didn't verify your test case, but after looking at the code I thought
there was a bit too much churn and the new conditions looked quite messy
and unexplained.  It seems simpler to be explicit at the start about
what we're doing, and keep nindexes=0 for partitioned tables; with that,
the code works unchanged because the "for" loops do nothing without
having to check for anything.  My proposal is attached.

I did run the tests and they do pass, but I didn't look very closely at
what the tests are actually doing.

I noticed that part of that comment seems to be a leftover from ... I
don't know when: "We do not analyze index columns if there was an
explicit column list in the ANALYZE command, however."  I suppose this
is about some code that was removed, but I didn't dig into it.

-- 
Álvaro Herrera                        Valdivia, Chile
"How strange it is to find the words "Perl" and "saner" in such close
proximity, with no apparent sense of irony. I doubt that Larry himself
could have managed it."         (ncm, http://lwn.net/Articles/174769/)

Commits

  1. Don't reset relhasindex for partitioned tables on ANALYZE

  2. Set pg_class.reltuples for partitioned tables

  3. autovacuum: handle analyze for partitioned tables