postgresql/contrib
Tom Lane 7519bd16d1 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 06:26:53 -04:00
amcheck Fix some typos 2020-11-14 11:43:10 +09:00
auth_delay Update copyrights for 2020 2020-01-01 12:21:45 -05:00
auto_explain Add the option to report WAL usage in EXPLAIN and auto_explain. 2020-04-06 08:02:15 +05:30
bloom Invent "amadjustmembers" AM method for validating opclass members. 2020-08-01 17:12:47 -04:00
bool_plperl Create contrib/bool_plperl to provide a bool transform for PL/Perl[U]. 2020-03-06 17:11:23 -05:00
btree_gin Remove support for upgrading extensions from "unpackaged" state. 2020-02-19 16:59:14 -05:00
btree_gist Expose internal function for converting int64 to numeric 2020-09-09 20:16:28 +02:00
citext Make contrib modules' installation scripts more secure. 2020-08-10 10:44:42 -04:00
cube Make contrib modules' installation scripts more secure. 2020-08-10 10:44:42 -04:00
dblink Improve hash_create()'s API for some added robustness. 2020-12-15 11:38:53 -05:00
dict_int Preserve integer and float values accurately in (de)serialize_deflist. 2020-03-10 12:30:02 -04:00
dict_xsyn Remove support for upgrading extensions from "unpackaged" state. 2020-02-19 16:59:14 -05:00
earthdistance Make contrib modules' installation scripts more secure. 2020-08-10 10:44:42 -04:00
file_fdw Remove leftover comments, left behind by removal of WITH OIDS. 2020-11-30 10:26:43 +02:00
fuzzystrmatch Remove support for upgrading extensions from "unpackaged" state. 2020-02-19 16:59:14 -05:00
hstore Allow subscripting of hstore values. 2020-12-11 18:58:21 -05:00
hstore_plperl Make contrib modules' installation scripts more secure. 2020-08-10 10:44:42 -04:00
hstore_plpython Split all OBJS style lines in makefiles into one-line-per-entry style. 2019-11-05 14:41:07 -08:00
intagg Make contrib modules' installation scripts more secure. 2020-08-10 10:44:42 -04:00
intarray Make contrib modules' installation scripts more secure. 2020-08-10 10:44:42 -04:00
isn Remove support for upgrading extensions from "unpackaged" state. 2020-02-19 16:59:14 -05:00
jsonb_plperl Expose internal function for converting int64 to numeric 2020-09-09 20:16:28 +02:00
jsonb_plpython Support infinity and -infinity in the numeric data type. 2020-07-22 19:19:44 -04:00
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 10:44:42 -04:00
ltree_plpython Improve error messages in ltree_in and lquery_in. 2020-03-31 11:14:42 -04:00
oid2name Remove arbitrary restrictions on password length. 2020-09-03 20:09:18 -04:00
old_snapshot Add new 'old_snapshot' contrib module. 2020-09-24 13:55:47 -04:00
pageinspect Remove unused parameter 2020-09-04 08:08:23 +02:00
passwordcheck passwordcheck: Log cracklib diagnostics 2020-08-28 08:18:24 +02:00
pg_buffercache Remove support for upgrading extensions from "unpackaged" state. 2020-02-19 16:59:14 -05:00
pg_freespacemap Remove support for upgrading extensions from "unpackaged" state. 2020-02-19 16:59:14 -05:00
pg_prewarm Fix race condition between shutdown and unstarted background workers. 2020-12-24 17:00:43 -05:00
pg_standby pg_standby: Don't use HAVE_WORKING_LINK 2020-03-03 08:54:44 +01:00
pg_stat_statements Fix typos and grammar in docs and comments 2020-12-24 17:05:49 +09:00
pg_surgery pg_surgery: Try to stabilize regression tests. 2020-09-18 13:26:48 -04:00
pg_trgm Handle equality operator in contrib/pg_trgm 2020-11-15 08:52:35 +03:00
pg_visibility snapshot scalability: Don't compute global horizons while building snapshots. 2020-08-12 16:03:49 -07:00
pgcrypto Refactor logic to check for ASCII-only characters in string 2020-12-21 09:37:11 +09:00
pgrowlocks Avoid holding a directory FD open across assorted SRF calls. 2020-03-16 21:05:52 -04:00
pgstattuple Redefine pg_class.reltuples to be -1 before the first VACUUM or ANALYZE. 2020-08-30 12:21:51 -04:00
postgres_fdw Improve hash_create()'s API for some added robustness. 2020-12-15 11:38:53 -05:00
seg Make contrib modules' installation scripts more secure. 2020-08-10 10:44:42 -04:00
sepgsql Fix expected output: the order of agg permission checks changed. 2020-11-24 12:50:16 +02:00
spi Remove support for upgrading extensions from "unpackaged" state. 2020-02-19 16:59:14 -05:00
sslinfo Use be_tls_* API for SSL information in sslinfo 2020-11-03 09:47:36 +01:00
start-scripts Remove contrib/start-scripts/osx/. 2017-11-17 12:53:20 -05:00
tablefunc Improve hash_create()'s API for some added robustness. 2020-12-15 11:38:53 -05:00
tcn Mark some contrib modules as "trusted". 2020-02-13 15:02:35 -05:00
test_decoding Fix 'skip-empty-xacts' option in test_decoding for streaming mode. 2020-11-17 12:14:53 +05:30
tsm_system_rows Mark some contrib modules as "trusted". 2020-02-13 15:02:35 -05:00
tsm_system_time Mark some contrib modules as "trusted". 2020-02-13 15:02:35 -05:00
unaccent Update Unicode data to Unicode 13.0.0 and CLDR 37 2020-04-24 09:52:59 +02:00
uuid-ossp Improve some code around cryptohash functions 2020-12-14 12:38:13 +09:00
vacuumlo Remove arbitrary restrictions on password length. 2020-09-03 20:09:18 -04:00
xml2 Remove support for upgrading extensions from "unpackaged" state. 2020-02-19 16:59:14 -05:00
contrib-global.mk Respect TEMP_CONFIG when pg_regress_check and friends are called 2016-02-27 12:28:21 -05:00
Makefile Add new 'old_snapshot' contrib module. 2020-09-24 13:55:47 -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.