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  1. doc: Update pg_dump/dumpall/upgrade about handling of external statistics

  1. BUG #19529: Documentation appears inconsistent with pg_dump --statistics behavior for CREATE STATISTICS objects

    The Post Office <noreply@postgresql.org> — 2026-06-19T07:17:44Z

    The following bug has been logged on the website:

Bug reference:      19529
Logged by:          Igi Izumi
Email address:      igi@sraoss.co.jp
PostgreSQL version: 19beta1
Operating system:   Rocky Linux 10.2 x86_64
Description:        

The PostgreSQL 19 pg_dump documentation currently states:
"When --statistics is specified, pg_dump will include most optimizer
statistics in the resulting dump file. This does not include all statistics,
such as those created explicitly with CREATE STATISTICS, custom statistics
added by an extension, or statistics collected by the cumulative statistics
system. Therefore, it may still be useful to run ANALYZE after restoring
from a dump file to ensure optimal performance; see Section 24.1.3 and
Section 24.1.6 for more information."
https://www.postgresql.org/docs/19/app-pgdump.html

However, PostgreSQL 19 introduced support for restoring extended statistics
with pg_restore_extended_stats(), and the following commits appear to add
support for dumping and restoring CREATE STATISTICS data:

・Include extended statistics data in pg_dump
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=c32fb29e9

・Add pg_restore_extended_stats()
https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=0e80f3f88

Because of these changes, it appears that statistics created explicitly with
CREATE STATISTICS are now handled by pg_dump --statistics, while the
PostgreSQL 19 documentation still states that they are not included.

Could you please confirm whether the documentation is correct, or whether
this is a documentation bug?

  2. Re: BUG #19529: Documentation appears inconsistent with pg_dump --statistics behavior for CREATE STATISTICS objects

    Fujii Masao <masao.fujii@gmail.com> — 2026-06-20T15:55:34Z

    On Sat, Jun 20, 2026 at 8:19 PM PG Bug reporting form
<noreply@postgresql.org> wrote:
>
> The following bug has been logged on the website:
>
> Bug reference:      19529
> Logged by:          Igi Izumi
> Email address:      igi@sraoss.co.jp
> PostgreSQL version: 19beta1
> Operating system:   Rocky Linux 10.2 x86_64
> Description:
>
> The PostgreSQL 19 pg_dump documentation currently states:
> "When --statistics is specified, pg_dump will include most optimizer
> statistics in the resulting dump file. This does not include all statistics,
> such as those created explicitly with CREATE STATISTICS, custom statistics
> added by an extension, or statistics collected by the cumulative statistics
> system. Therefore, it may still be useful to run ANALYZE after restoring
> from a dump file to ensure optimal performance; see Section 24.1.3 and
> Section 24.1.6 for more information."
> https://www.postgresql.org/docs/19/app-pgdump.html
>
> However, PostgreSQL 19 introduced support for restoring extended statistics
> with pg_restore_extended_stats(), and the following commits appear to add
> support for dumping and restoring CREATE STATISTICS data:
>
> ・Include extended statistics data in pg_dump
> https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=c32fb29e9
>
> ・Add pg_restore_extended_stats()
> https://git.postgresql.org/gitweb/?p=postgresql.git;a=commitdiff;h=0e80f3f88
>
> Because of these changes, it appears that statistics created explicitly with
> CREATE STATISTICS are now handled by pg_dump --statistics, while the
> PostgreSQL 19 documentation still states that they are not included.
>
> Could you please confirm whether the documentation is correct, or whether
> this is a documentation bug?

This looks like a documentation oversight in (maybe) the commit that
added extended statistics support to pg_dump.

I say that because I confirmed that pg_dump --statistics does dump
the extended statistics for table t after running:

    CREATE TABLE t (i int, j int);
    INSERT INTO t SELECT n, n FROM generate_series(1, 100) n;
    CREATE STATISTICS ON i, j FROM t;
    ANALYZE t;

Regards,

-- 
Fujii Masao

  3. Re: BUG #19529: Documentation appears inconsistent with pg_dump --statistics behavior for CREATE STATISTICS objects

    Michael Paquier <michael@paquier.xyz> — 2026-06-22T07:50:34Z

    On Sun, Jun 21, 2026 at 12:55:34AM +0900, Fujii Masao wrote:
> This looks like a documentation oversight in (maybe) the commit that
> added extended statistics support to pg_dump.

This is a doc oversight.  While working on the support of extstats
for this release, I have looked at holes like this one in the docs,
and did not consider the pattern of a linkend based on
sql-createstatistics.

The report mentions pg_dump, but we have the same wrong pattern in the
doc pages for pg_dumpall and pg_upgrade, leading me to the attached
for these three holes.

Thoughts?
--
Michael