postgres

Heikki Linnakangas b8bff07daa Make ResourceOwners more easily extensible. Instead of having a separate array/hash for each resource kind, use a single array and hash to hold all kinds of resources. This makes it possible to introduce new resource "kinds" without having to modify the ResourceOwnerData struct. In particular, this makes it possible for extensions to register custom resource kinds. The old approach was to have a small array of resources of each kind, and if it fills up, switch to a hash table. The new approach also uses an array and a hash, but now the array and the hash are used at the same time. The array is used to hold the recently added resources, and when it fills up, they are moved to the hash. This keeps the access to recent entries fast, even when there are a lot of long-held resources. All the resource-specific ResourceOwnerEnlarge(), ResourceOwnerRemember(), and ResourceOwnerForget*() functions have been replaced with three generic functions that take resource kind as argument. For convenience, we still define resource-specific wrapper macros around the generic functions with the old names, but they are now defined in the source files that use those resource kinds. The release callback no longer needs to call ResourceOwnerForget on the resource being released. ResourceOwnerRelease unregisters the resource from the owner before calling the callback. That needed some changes in bufmgr.c and some other files, where releasing the resources previously always called ResourceOwnerForget. Each resource kind specifies a release priority, and ResourceOwnerReleaseAll releases the resources in priority order. To make that possible, we have to restrict what you can do between phases. After calling ResourceOwnerRelease(), you are no longer allowed to remember any more resources in it or to forget any previously remembered resources by calling ResourceOwnerForget. There was one case where that was done previously. At subtransaction commit, AtEOSubXact_Inval() would handle the invalidation messages and call RelationFlushRelation(), which temporarily increased the reference count on the relation being flushed. We now switch to the parent subtransaction's resource owner before calling AtEOSubXact_Inval(), so that there is a valid ResourceOwner to temporarily hold that relcache reference. Other end-of-xact routines make similar calls to AtEOXact_Inval() between release phases, but I didn't see any regression test failures from those, so I'm not sure if they could reach a codepath that needs remembering extra resources. There were two exceptions to how the resource leak WARNINGs on commit were printed previously: llvmjit silently released the context without printing the warning, and a leaked buffer io triggered a PANIC. Now everything prints a WARNING, including those cases. Add tests in src/test/modules/test_resowner. Reviewed-by: Aleksander Alekseev, Michael Paquier, Julien Rouhaud Reviewed-by: Kyotaro Horiguchi, Hayato Kuroda, Álvaro Herrera, Zhihong Yu Reviewed-by: Peter Eisentraut, Andres Freund Discussion: https://www.postgresql.org/message-id/cbfabeb0-cd3c-e951-a572-19b365ed314d%40iki.fi		2 years ago
config	Remove distprep	2 years ago
contrib	citext: Allow tests to pass in OpenSSL FIPS mode	2 years ago
doc	Remove distprep	2 years ago
src	Make ResourceOwners more easily extensible.	2 years ago
.cirrus.star	Remove duplicate words in docs and code comments.	2 years ago
.cirrus.tasks.yml	Use "template" data directory in tests	2 years ago
.cirrus.yml	ci: Make compute resources for CI configurable	2 years ago
.dir-locals.el	Make Emacs perl-mode indent more like perltidy.	7 years ago
.editorconfig	Add .editorconfig	6 years ago
.git-blame-ignore-revs	Add "Add trailing commas to enum definitions" to .git-blame-ignore-revs	2 years ago
.gitattributes	gitattributes: Ignore imported pg_bsd_indent code for whitespace checks	2 years ago
.gitignore	Update top-level .gitignore.	3 years ago
COPYRIGHT	Update copyright for 2023	3 years ago
GNUmakefile.in	Remove distprep	2 years ago
HISTORY	Canonicalize some URLs	5 years ago
Makefile	Dynamically find correct installation docs in Makefile.	3 years ago
README	Canonicalize some URLs	5 years ago
README.git	Canonicalize some URLs	5 years ago
aclocal.m4	autoconf: Move export_dynamic determination to configure	3 years ago
configure	Remove distprep	2 years ago
configure.ac	Log OpenSSL version in ./configure output	2 years ago
meson.build	Remove distprep	2 years ago
meson_options.txt	meson: Attach colon to keyword argument	2 years ago

README

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/.