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Michael Paquier c1201ffcfb Remove assertion based on pending_since in pgstat_report_stat()
This assertion, based on pending_since (timestamp used to prevent stats
reports to be too frequent or should a partial flush happen), is reached
when it is found that no data can be flushed but a previous call of
pgstat_report_stat() determined that some stats data has been found as
in need of a flush.  So pending_since is set when some stats data is
pending (in non-force mode) or if report attempts are too frequent, and
reset to 0 once all stats have been flushed.

Since 5cbbe70a9c, WAL senders have begun to report their stats on a
periodic basis for IO stats in v16~ and backend stats on HEAD, creating
some friction with the concurrent pgstat_report_stat() calls that can
happen in the context of a WAL sender (shutdown callback doing a final
report or backend-related code paths).  This problem is the cause of
spurious failures in the TAP tests.

In theory, this assertion can be also reached in v15, even if that's
very unlikely.  For example, a process, say a background worker, could
do periodic and direct stats flushes with concurrent calls of
pgstat_report_stat() that could cause conflicting values of
pending_since.  This can be done with WAL or SLRU stats flushes using
pgstat_flush_wal() or pgstat_slru_flush().  HEAD makes this situation
easier to happen with custom cumulative stats.

This commit removes the assertion altogether, per discussion, as it is
more useful to keep the state of things as they are for the WAL sender.
The assertion could use a special state based on for example
am_walsender, but I doubt that this would be meaningful in the long run
based on the other arguments raised while discussing this issue.

Reported-by: Tom Lane <tgl@sss.pgh.pa.us>
Reported-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/1489124.1744685908@sss.pgh.pa.us
Discussion: https://postgr.es/m/dwrkeszz6czvtkxzr5mqlciy652zau5qqnm3cp5f3p2po74ppk@omg4g3cc6dgq
Backpatch-through: 15
2025-04-23 13:54:57 +09:00
config Log LLVM library version in configure output. 2023-10-22 14:24:04 +13:00
contrib Be more wary of corrupt data in pageinspect's heap_page_items(). 2025-04-19 16:37:42 -04:00
doc Doc: reword text explaining the --maintenance-db option 2025-04-22 14:57:25 +12:00
src Remove assertion based on pending_since in pgstat_report_stat() 2025-04-23 13:54:57 +09:00
.cirrus.star ci: Prepare to make compute resources for CI configurable 2023-08-23 15:15:29 -07:00
.cirrus.tasks.yml ci: Upgrade FreeBSD image 2025-03-05 10:29:05 -05:00
.cirrus.yml ci: Make compute resources for CI configurable 2023-08-23 15:15:29 -07:00
.dir-locals.el Make Emacs perl-mode indent more like perltidy. 2019-01-13 11:32:31 -08:00
.editorconfig Add .editorconfig 2019-12-18 09:13:13 +01:00
.git-blame-ignore-revs Backpatch addition of .git-blame-ignore-revs 2022-08-05 19:36:24 +02:00
.gitattributes Exclude LLVM files from whitespace checks 2024-11-27 11:09:48 +01:00
.gitignore Add portlock directory to .gitignore 2022-11-26 07:47:01 -05:00
aclocal.m4 Probe $PROVE not $PERL while checking for modules needed by TAP tests. 2021-11-22 12:54:52 -05:00
configure Fix detection and handling of strchrnul() for macOS 15.4. 2025-04-01 16:49:51 -04:00
configure.ac Fix detection and handling of strchrnul() for macOS 15.4. 2025-04-01 16:49:51 -04:00
COPYRIGHT Update copyright for 2025 2025-01-01 11:21:54 -05:00
GNUmakefile.in Remove temporary portlock directory during make [dist]clean. 2022-11-26 10:30:46 -05:00
HISTORY Canonicalize some URLs 2020-02-10 20:47:50 +01:00
Makefile Dynamically find correct installation docs in Makefile. 2022-01-19 14:48:25 +01:00
README Canonicalize some URLs 2020-02-10 20:47:50 +01:00
README.git Canonicalize some URLs 2020-02-10 20:47:50 +01:00

PostgreSQL Database Management System
=====================================

This directory contains the source code distribution of the PostgreSQL
database management system.

PostgreSQL is an advanced object-relational database management system
that supports an extended subset of the SQL standard, including
transactions, foreign keys, subqueries, triggers, user-defined types
and functions.  This distribution also contains C language bindings.

PostgreSQL has many language interfaces, many of which are listed here:

	https://www.postgresql.org/download/

See the file INSTALL for instructions on how to build and install
PostgreSQL.  That file also lists supported operating systems and
hardware platforms and contains information regarding any other
software packages that are required to build or run the PostgreSQL
system.  Copyright and license information can be found in the
file COPYRIGHT.  A comprehensive documentation set is included in this
distribution; it can be read as described in the installation
instructions.

The latest version of this software may be obtained at
https://www.postgresql.org/download/.  For more information look at our
web site located at https://www.postgresql.org/.