postgresql/contrib
Tom Lane b99b6b9d6c Fix race condition between shutdown and unstarted background workers.
If a database shutdown (smart or fast) is commanded between the time
some process decides to request a new background worker and the time
that the postmaster can launch that worker, then nothing happens
because the postmaster won't launch any bgworkers once it's exited
PM_RUN state.  This is fine ... unless the requesting process is
waiting for that worker to finish (or even for it to start); in that
case the requestor is stuck, and only manual intervention will get us
to the point of being able to shut down.

To fix, cancel pending requests for workers when the postmaster sends
shutdown (SIGTERM) signals, and similarly cancel any new requests that
arrive after that point.  (We can optimize things slightly by only
doing the cancellation for workers that have waiters.)  To fit within
the existing bgworker APIs, the "cancel" is made to look like the
worker was started and immediately stopped, causing deregistration of
the bgworker entry.  Waiting processes would have to deal with
premature worker exit anyway, so this should introduce no bugs that
weren't there before.  We do have a side effect that registration
records for restartable bgworkers might disappear when theoretically
they should have remained in place; but since we're shutting down,
that shouldn't matter.

Back-patch to v10.  There might be value in putting this into 9.6
as well, but the management of bgworkers is a bit different there
(notably see 8ff518699) and I'm not convinced it's worth the effort
to validate the patch for that branch.

Discussion: https://postgr.es/m/661570.1608673226@sss.pgh.pa.us
2020-12-24 17:00:43 -05:00
..
adminpack Read until EOF vice stat-reported size in read_binary_file 2020-07-04 06:29:03 -04:00
amcheck Restore lost amcheck TOAST test coverage. 2020-07-31 15:34:23 -07:00
auth_delay Update copyright for 2018 2018-01-02 23:30:12 -05:00
auto_explain Fix contrib/auto_explain to not cause problems in parallel workers. 2019-06-03 18:06:04 -04:00
bloom Fix failure with lock mode used for custom relation options 2019-09-25 10:08:30 +09:00
btree_gin Clean up warnings from -Wimplicit-fallthrough. 2018-05-01 19:35:08 -04:00
btree_gist Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
citext Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
cube Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
dblink Initialize dblink remoteConn struct in all cases 2020-05-28 13:45:02 -04:00
dict_int Ensure maxlen is at leat 1 in dict_int 2019-12-03 18:41:29 +01:00
dict_xsyn Avoid unnecessary use of pg_strcasecmp for already-downcased identifiers. 2018-01-26 18:25:14 -05:00
earthdistance Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
file_fdw Ensure that foreign scans with lateral refs are planned correctly. 2019-02-07 13:11:13 -05:00
fuzzystrmatch Replace search.cpan.org with metacpan.org 2018-06-29 22:02:20 +09:00
hstore Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
hstore_plperl Still further rethinking of build changes for macOS Mojave. 2018-10-18 14:55:23 -04:00
hstore_plpython Fix volatile vs. pointer confusion 2019-03-15 08:37:48 +01:00
intagg Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
intarray Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
isn Provide for contrib and pgxs modules to install include files. 2018-07-31 19:58:39 +01:00
jsonb_plperl Fix handling of "undef" in contrib/jsonb_plperl. 2019-08-04 14:05:35 -04:00
jsonb_plpython In jsonb_plpython.c, suppress warning message from gcc 10. 2020-01-30 18:26:15 -05:00
lo Fix bogus CALLED_AS_TRIGGER() defenses. 2020-04-03 11:24:56 -04:00
ltree Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
ltree_plpython Fix out-of-tree build for transform modules. 2018-09-16 19:13:59 +01:00
oid2name Switch client-side code to include catalog/pg_foo_d.h not pg_foo.h. 2018-04-08 13:59:52 -04:00
pageinspect Paper over bt_metap() oldest_xact bug in backbranches. 2020-03-11 14:15:00 -07:00
passwordcheck Fix handling of previous password hooks in passwordcheck 2019-08-01 09:38:02 +09:00
pg_buffercache Phase 2 of pgindent updates. 2017-06-21 15:19:25 -04:00
pg_freespacemap Default monitoring roles 2017-03-30 14:18:53 -04:00
pg_prewarm Fix race condition between shutdown and unstarted background workers. 2020-12-24 17:00:43 -05:00
pg_standby Avoid using potentially-under-aligned page buffers. 2018-09-01 15:27:13 -04:00
pg_stat_statements Revoke pg_stat_statements_reset() permissions 2018-09-25 09:56:41 +09:00
pg_trgm pg_trgm: fix crash in 2-item picksplit 2020-11-12 14:57:04 +00:00
pg_visibility Update copyright for 2018 2018-01-02 23:30:12 -05:00
pgcrypto pgcrypto: Detect errors with EVP calls from OpenSSL 2020-12-08 15:22:48 +09:00
pgrowlocks Avoid holding a directory FD open across assorted SRF calls. 2020-03-16 21:05:54 -04:00
pgstattuple pgstatindex, pageinspect: handle partitioned indexes 2018-05-09 14:22:59 -03:00
postgres_fdw Fix and simplify some usages of TimestampDifference(). 2020-11-10 22:51:56 -05:00
seg Make contrib modules' installation scripts more secure. 2020-08-10 10:44:43 -04:00
sepgsql Fix cache reference leak in contrib/sepgsql. 2020-04-16 14:45:54 -04:00
spi Prevent accidental linking of system-supplied copies of libpq.so etc. 2018-04-03 16:26:05 -04:00
sslinfo Phase 3 of pgindent updates. 2017-06-21 15:35:54 -04:00
start-scripts Remove contrib/start-scripts/osx/. 2017-11-17 12:53:20 -05:00
tablefunc Disallow null category in crosstab_hash 2019-12-23 13:33:42 -05:00
tcn Post-feature-freeze pgindent run. 2018-04-26 14:47:16 -04:00
test_decoding Propagate ALTER TABLE ... SET STORAGE to indexes 2020-05-08 09:30:57 +02:00
tsm_system_rows Update copyright for 2018 2018-01-02 23:30:12 -05:00
tsm_system_time Update copyright for 2018 2018-01-02 23:30:12 -05:00
unaccent Make contrib/unaccent's unaccent() function work when not in search path. 2018-09-06 10:49:45 -04:00
uuid-ossp Update copyright for 2018 2018-01-02 23:30:12 -05:00
vacuumlo Fix copy-pasto in freeing memory on error in vacuumlo. 2019-06-07 12:43:55 +03:00
xml2 Phase 3 of pgindent updates. 2017-06-21 15:35:54 -04:00
contrib-global.mk Respect TEMP_CONFIG when pg_regress_check and friends are called 2016-02-27 12:28:21 -05:00
Makefile Transforms for jsonb to PL/Perl 2018-04-03 09:47:18 -04:00
README Rename 'gmake' to 'make' in docs and recommended commands 2014-02-12 17:29:19 -05:00

The PostgreSQL contrib tree
---------------------------

This subtree contains porting tools, analysis utilities, and plug-in
features that are not part of the core PostgreSQL system, mainly
because they address a limited audience or are too experimental to be
part of the main source tree.  This does not preclude their
usefulness.

User documentation for each module appears in the main SGML
documentation.

When building from the source distribution, these modules are not
built automatically, unless you build the "world" target.  You can
also build and install them all by running "make all" and "make
install" in this directory; or to build and install just one selected
module, do the same in that module's subdirectory.

Some directories supply new user-defined functions, operators, or
types.  To make use of one of these modules, after you have installed
the code you need to register the new SQL objects in the database
system by executing a CREATE EXTENSION command.  In a fresh database,
you can simply do

    CREATE EXTENSION module_name;

See the PostgreSQL documentation for more information about this
procedure.