Commit Graph

50464 Commits

Author SHA1 Message Date
Alexander Korotkov 62097a4cc8 Fix selectivity estimation @> (anymultirange, anyrange) operator
Attempt to get selectivity estimation for @> (anymultirange, anyrange) operator
caused an error in buildfarm, because this operator was missed in switch()
of calc_hist_selectivity().  Fix that and also make regression tests reliably
check that selectivity estimation for (multi)ranges doesn't fall.  Previously,
whether we test selectivity estimation for (multi)ranges depended on
whether autovacuum managed to gather concurrently to the test.

Reported-by: Michael Paquier
Discussion: https://postgr.es/m/X%2BwmgjRItuvHNBeV%40paquier.xyz
2020-12-30 20:31:15 +03:00
Tom Lane 860fe27ee1 Fix up usage of krb_server_keyfile GUC parameter.
secure_open_gssapi() installed the krb_server_keyfile setting as
KRB5_KTNAME unconditionally, so long as it's not empty.  However,
pg_GSS_recvauth() only installed it if KRB5_KTNAME wasn't set already,
leading to a troubling inconsistency: in theory, clients could see
different sets of server principal names depending on whether they
use GSSAPI encryption.  Always using krb_server_keyfile seems like
the right thing, so make both places do that.  Also fix up
secure_open_gssapi()'s lack of a check for setenv() failure ---
it's unlikely, surely, but security-critical actions are no place
to be sloppy.

Also improve the associated documentation.

This patch does nothing about secure_open_gssapi()'s use of setenv(),
and indeed causes pg_GSS_recvauth() to use it too.  That's nominally
against project portability rules, but since this code is only built
with --with-gssapi, I do not feel a need to do something about this
in the back branches.  A fix will be forthcoming for HEAD though.

Back-patch to v12 where GSSAPI encryption was introduced.  The
dubious behavior in pg_GSS_recvauth() goes back further, but it
didn't have anything to be inconsistent with, so let it be.

Discussion: https://postgr.es/m/2187460.1609263156@sss.pgh.pa.us
2020-12-30 11:38:42 -05:00
Michael Paquier e665769e6d Sanitize IF NOT EXISTS in EXPLAIN for CTAS and matviews
IF NOT EXISTS was ignored when specified in an EXPLAIN query for CREATE
MATERIALIZED VIEW or CREATE TABLE AS.  Hence, if this clause was
specified, the caller would get a failure if the relation already
exists instead of a success with a NOTICE message.

This commit makes the behavior of IF NOT EXISTS in EXPLAIN consistent
with the non-EXPLAIN'd DDL queries, preventing a failure with IF NOT
EXISTS if the relation to-be-created already exists.  The skip is done
before the SELECT query used for the relation is planned or executed,
and a "dummy" plan is generated instead depending on the format used by
EXPLAIN.

Author: Bharath Rupireddy
Reviewed-by: Zhijie Hou, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACVa3oJ9O_wcGd+FtHWZds04dEKcakxphGz5POVgD4wC7Q@mail.gmail.com
2020-12-30 21:23:24 +09:00
Amit Kapila 0aa8a01d04 Extend the output plugin API to allow decoding of prepared xacts.
This adds six methods to the output plugin API, adding support for
streaming changes of two-phase transactions at prepare time.

* begin_prepare
* filter_prepare
* prepare
* commit_prepared
* rollback_prepared
* stream_prepare

Most of this is a simple extension of the existing methods, with the
semantic difference that the transaction is not yet committed and maybe
aborted later.

Until now two-phase transactions were translated into regular transactions
on the subscriber, and the GID was not forwarded to it. None of the
two-phase commands were communicated to the subscriber.

This patch provides the infrastructure for logical decoding plugins to be
informed of two-phase commands Like PREPARE TRANSACTION, COMMIT PREPARED
and ROLLBACK PREPARED commands with the corresponding GID.

This also extends the 'test_decoding' plugin, implementing these new
methods.

This commit simply adds these new APIs and the upcoming patch to "allow
the decoding at prepare time in ReorderBuffer" will use these APIs.

Author: Ajin Cherian and Amit Kapila based on previous work by Nikhil Sontakke and Stas Kelvich
Reviewed-by: Amit Kapila, Peter Smith, Sawada Masahiko, and Dilip Kumar
Discussion:
https://postgr.es/m/02DA5F5E-CECE-4D9C-8B4B-418077E2C010@postgrespro.ru
https://postgr.es/m/CAMGcDxeqEpWj3fTXwqhSwBdXd2RS9jzwWscO-XbeCfso6ts3+Q@mail.gmail.com
2020-12-30 16:17:26 +05:30
Noah Misch fa744697c7 In pg_upgrade cross-version test, handle postfix operators.
Commit 1ed6b89563 eliminated support for
them, so drop them from regression databases before upgrading.  This is
necessary but not sufficient for testing v13 -> v14 upgrades.

Discussion: https://postgr.es/m/449144.1600439950@sss.pgh.pa.us
2020-12-30 01:43:43 -08:00
Noah Misch 52202bb396 In pg_upgrade cross-version test, handle lack of oldstyle_length().
This suffices for testing v12 -> v13; some other version pairs need more
changes.  Back-patch to v10, which removed the function.
2020-12-30 01:43:43 -08:00
Michael Paquier 107a2d4204 Remove references to libpq_srcdir in adminpack and old_snapshot
Those two modules included references to libpq's source path, without
using anything from libpq.  Some copy-pastos done when each module was
created are likely at the origin of those useless references (aecf5ee
for old_snapshot, fe59e56 for adminpack).

Reviewed-by: Tom Lane, David Rowley
Discussion: https://postgr.es/m/X+LQpfLyk7jgzUki@paquier.xyz
2020-12-30 12:38:16 +09:00
Tom Lane f20dc2c8dd Doc: fix up PDF build warnings from over-width table columns.
Addition of multirange info to tables 8.27 and 65.1 made them start
throwing "exceed the available area" warnings in PDF docs builds.

For 8.27, twiddling the existing column width hints was enough to
fix this.  For 65.1, I twiddled the widths a little, but to really
fix it I had to insert a space after each comma in the table, to
allow a line break to occur there.  (This seemed easier to read
and maintain than the alternative of inserting &zwsp; entities.)

Per buildfarm.
2020-12-29 20:44:03 -05:00
Tom Lane 1f9158ba48 Suppress log spam from multiple reports of SIGQUIT shutdown.
When the postmaster sends SIGQUIT to its children, there's no real
need for all the children to log that fact; the postmaster already
made a log entry about it, so adding perhaps dozens or hundreds of
child-process log entries adds nothing of value.  So, let's introduce
a new ereport level to specify "WARNING, but never send to log" and
use that for these messages.

Such a change wouldn't have been desirable before commit 7e784d1dc,
because if someone manually SIGQUIT's a backend, we *do* want to log
that.  But now we can tell the difference between a signal that was
issued by the postmaster and one that was not with reasonable
certainty.

While we're here, also clear error_context_stack before ereport'ing,
to prevent error callbacks from being invoked in the signal-handler
context.  This should reduce the odds of getting hung up while trying
to notify the client.

Per a suggestion from Andres Freund.

Discussion: https://postgr.es/m/20201225230331.hru3u6obyy6j53tk@alap3.anarazel.de
2020-12-29 18:02:38 -05:00
Alexander Korotkov db6335b5b1 Add support of multirange matching to the existing range GiST indexes
6df7a9698b has introduced a set of operators between ranges and multiranges.
Existing GiST indexes for ranges could easily support majority of them.
This commit adds support for new operators to the existing range GiST indexes.
New operators resides the same strategy numbers as existing ones.  Appropriate
check function is determined using the subtype.

Catversion is bumped.
2020-12-29 23:36:43 +03:00
Alexander Korotkov d1d61a8b23 Improve the signature of internal multirange functions
There is a set of *_internal() functions exposed in
include/utils/multirangetypes.h.  This commit improves the signatures of these
functions in two ways.
 * Add const qualifies where applicable.
 * Replace multirange typecache argument with range typecache argument.
   Multirange typecache was used solely to find the range typecache.  At the
   same time, range typecache is easier for the caller to find.
2020-12-29 23:35:38 +03:00
Alexander Korotkov 4d7684cc75 Implement operators for checking if the range contains a multirange
We have operators for checking if the multirange contains a range but don't
have the opposite.  This commit improves completeness of the operator set by
adding two new operators: @> (anyrange,anymultirange) and
<@(anymultirange,anyrange).

Catversion is bumped.
2020-12-29 23:35:33 +03:00
Alexander Korotkov a5b81b6f00 Fix bugs in comparison functions for multirange_bsearch_match()
Two functions multirange_range_overlaps_bsearch_comparison() and
multirange_range_contains_bsearch_comparison() contain bugs of returning -1
instead of 1.  This commit fixes these bugs and adds corresponding regression
tests.
2020-12-29 23:35:26 +03:00
Michael Paquier 1b3433e25f doc: Improve description of min_dynamic_shared_memory
While on it, fix one oversight in 90fbf7c, that introduced a reference
to an incorrect value for the compression level of pg_dump.

Author: Justin Pryzby
Reviewed-by: Thomas Munro, Michael Paquier
Discussion: https://postgr.es/m/CA+hUKGJRTLWWPcQfjm_xaOk98M8aROK903X92O0x-4vLJPWrrA@mail.gmail.com
2020-12-29 16:49:14 +09:00
Tom Lane 3995c42498 Improve log messages related to pg_hba.conf not matching a connection.
Include details on whether GSS encryption has been activated;
since we added "hostgssenc" type HBA entries, that's relevant info.

Kyotaro Horiguchi and Tom Lane.  Back-patch to v12 where
GSS encryption was introduced.

Discussion: https://postgr.es/m/e5b0b6ed05764324a2f3fe7acfc766d5@smhi.se
2020-12-28 17:58:58 -05:00
Tom Lane 622ae4621e Fix assorted issues in backend's GSSAPI encryption support.
Unrecoverable errors detected by GSSAPI encryption can't just be
reported with elog(ERROR) or elog(FATAL), because attempting to
send the error report to the client is likely to lead to infinite
recursion or loss of protocol sync.  Instead make this code do what
the SSL encryption code has long done, which is to just report any
such failure to the server log (with elevel COMMERROR), then pretend
we've lost the connection by returning errno = ECONNRESET.

Along the way, fix confusion about whether message translation is done
by pg_GSS_error() or its callers (the latter should do it), and make
the backend version of that function work more like the frontend
version.

Avoid allocating the port->gss struct until it's needed; we surely
don't need to allocate it in the postmaster.

Improve logging of "connection authorized" messages with GSS enabled.
(As part of this, I back-patched the code changes from dc11f31a1.)

Make BackendStatusShmemSize() account for the GSS-related space that
will be allocated by CreateSharedBackendStatus().  This omission
could possibly cause out-of-shared-memory problems with very high
max_connections settings.

Remove arbitrary, pointless restriction that only GSS authentication
can be used on a GSS-encrypted connection.

Improve documentation; notably, document the fact that libpq now
prefers GSS encryption over SSL encryption if both are possible.

Per report from Mikael Gustavsson.  Back-patch to v12 where
this code was introduced.

Discussion: https://postgr.es/m/e5b0b6ed05764324a2f3fe7acfc766d5@smhi.se
2020-12-28 17:44:17 -05:00
Tom Lane ff6ce9a3a6 Fix bugs in libpq's GSSAPI encryption support.
The critical issue fixed here is that if a GSSAPI-encrypted connection
is successfully made, pqsecure_open_gss() cleared conn->allow_ssl_try,
as an admittedly-hacky way of preventing us from then trying to tunnel
SSL encryption over the already-encrypted connection.  The problem
with that is that if we abandon the GSSAPI connection because of a
failure during authentication, we would not attempt SSL encryption
in the next try with the same server.  This can lead to unexpected
connection failure, or silently getting a non-encrypted connection
where an encrypted one is expected.

Fortunately, we'd only manage to make a GSSAPI-encrypted connection
if both client and server hold valid tickets in the same Kerberos
infrastructure, which is a relatively uncommon environment.
Nonetheless this is a very nasty bug with potential security
consequences.  To fix, don't reset the flag, instead adding a
check for conn->gssenc being already true when deciding whether
to try to initiate SSL.

While here, fix some lesser issues in libpq's GSSAPI code:

* Use the need_new_connection stanza when dropping an attempted
GSSAPI connection, instead of partially duplicating that code.
The consequences of this are pretty minor: AFAICS it could only
lead to auth_req_received or password_needed remaining set when
they shouldn't, which is not too harmful.

* Fix pg_GSS_error() to not repeat the "mprefix" it's given multiple
times, and to notice any failure return from gss_display_status().

* Avoid gratuitous dependency on NI_MAXHOST in
pg_GSS_load_servicename().

Per report from Mikael Gustavsson.  Back-patch to v12 where
this code was introduced.

Discussion: https://postgr.es/m/e5b0b6ed05764324a2f3fe7acfc766d5@smhi.se
2020-12-28 15:43:44 -05:00
Tom Lane cf61b0734c Expose the default for channel_binding in PQconndefaults().
If there's a static default value for a connection option,
it should be shown in the PQconninfoOptions array.

Daniele Varrazzo

Discussion: https://postgr.es/m/CA+mi_8Zo8Rgn7p+6ZRY7QdDu+23ukT9AvoHNyPbgKACxwgGhZA@mail.gmail.com
2020-12-28 12:13:40 -05:00
Tom Lane 5f2e09bccc Further fix thinko in plpgsql memory leak fix.
There's a second call of get_eval_mcontext() that should also be
get_stmt_mcontext().  This is actually dead code, since no
interesting allocations happen before switching back to the
original context, but we should keep it in sync with the other
call to forestall possible future bugs.

Discussion: https://postgr.es/m/f075f7be-c654-9aa8-3ffc-e9214622f02a@enterprisedb.com
2020-12-28 11:55:23 -05:00
Tom Lane ea80d8d943 Fix thinko in plpgsql memory leak fix.
Commit a6b1f5365 intended to place the transient "target" list of
a CALL statement in the function's statement-lifespan context,
but I fat-fingered that and used get_eval_mcontext() instead of
get_stmt_mcontext().  The eval_mcontext belongs to the "simple
expression" infrastructure, which is destroyed at transaction end.
The net effect is that a CALL in a procedure to another procedure
that has OUT or INOUT parameters would fail if the called procedure
did a COMMIT.

Per report from Peter Eisentraut.  Back-patch to v11, like the
prior patch.

Discussion: https://postgr.es/m/f075f7be-c654-9aa8-3ffc-e9214622f02a@enterprisedb.com
2020-12-28 11:41:25 -05:00
Michael Paquier 643428c54b Fix inconsistent code with shared invalidations of snapshots
The code in charge of processing a single invalidation message has been
using since 568d413 the structure for relation mapping messages.  This
had fortunately no consequence as both locate the database ID at the
same location, but it could become a problem in the future if this area
of the code changes.

Author: Konstantin Knizhnik
Discussion: https://postgr.es/m/8044c223-4d3a-2cdb-42bf-29940840ce94@postgrespro.ru
Backpatch-through: 9.5
2020-12-28 22:16:49 +09:00
Fujii Masao e3ebcca843 postgres_fdw: Fix connection leak.
In postgres_fdw, the cached connections to foreign servers will not be
closed until the local session exits if the user mappings or foreign servers
that those connections depend on are dropped. Those connections can be
leaked.

To fix that connection leak issue, after a change to a pg_foreign_server
or pg_user_mapping catalog entry, this commit makes postgres_fdw close
the connections depending on that entry immediately if current
transaction has not used those connections yet. Otherwise, mark those
connections as invalid and then close them at the end of current transaction,
since they cannot be closed in the midst of the transaction using them.
Closed connections will be remade at the next opportunity if necessary.

Back-patch to all supported branches.

Author: Bharath Rupireddy
Reviewed-by: Zhihong Yu, Zhijie Hou, Fujii Masao
Discussion: https://postgr.es/m/CALj2ACVNcGH_6qLY-4_tXz8JLvA+4yeBThRfxMz7Oxbk1aHcpQ@mail.gmail.com
2020-12-28 19:56:13 +09:00
Bruce Momjian 3187ef7c46 Revert "Add key management system" (978f869b99) & later commits
The patch needs test cases, reorganization, and cfbot testing.
Technically reverts commits 5c31afc49d..e35b2bad1a (exclusive/inclusive)
and 08db7c63f3..ccbe34139b.

Reported-by: Tom Lane, Michael Paquier

Discussion: https://postgr.es/m/E1ktAAG-0002V2-VB@gemulon.postgresql.org
2020-12-27 21:37:42 -05:00
Jeff Davis facad31474 Second attempt to stabilize 05c02589.
Removing the EXPLAIN test to stabilize the buildfarm. The execution
test should still be effective to catch the bug even if the plan is
slightly different on different platforms.
2020-12-27 12:09:00 -08:00
Jeff Davis fa0fdf0510 Stabilize test introduced in 05c02589, per buildfarm.
In passing, make the capitalization match the rest of the file.

Reported-by: Tom Lane
2020-12-27 09:48:44 -08:00
Jeff Davis 05c0258966 Fix bug #16784 in Disk-based Hash Aggregation.
Before processing tuples, agg_refill_hash_table() was setting all
pergroup pointers to NULL to signal to advance_aggregates() that it
should not attempt to advance groups that had spilled.

The problem was that it also set the pergroups for sorted grouping
sets to NULL, which caused rescanning to fail.

Instead, change agg_refill_hash_table() to only set the pergroups for
hashed grouping sets to NULL; and when compiling the expression, pass
doSort=false.

Reported-by: Alexander Lakhin
Discussion: https://postgr.es/m/16784-7ff169bf2c3d1588%40postgresql.org
Backpatch-through: 13
2020-12-26 17:25:30 -08:00
Bruce Momjian ccbe34139b initdb: document that -K requires an argument
Reported-by: "Shinoda, Noriyoshi"

Discussion: https://postgr.es/m/TU4PR8401MB1152E92B4D44C81E496D6032EEDB0@TU4PR8401MB1152.NAMPRD84.PROD.OUTLOOK.COM

Author: "Shinoda, Noriyoshi"

Backpatch-through: msater
2020-12-26 10:00:05 -05:00
Bruce Momjian ba6725df36 auth commands: list specific commands to install in Makefile
Previously I used Makefile functions.

Backpatch-through: master
2020-12-26 09:25:05 -05:00
Bruce Momjian e174a6f193 pg_alterckey: remove TAP check rules from Makefile
Reported-by: Pavel Stehule, Michael Paquier

Discussion: https://postgr.es/m/CAFj8pRBRNo4co5bqCx4BLx1ZZ45Z_T-opPxA+u7SLp7gAtBpNA@mail.gmail.com

Backpatch-through: master
2020-12-26 09:03:12 -05:00
Bruce Momjian d7602afa2e Add scripts for retrieving the cluster file encryption key
Scripts are passphrase, direct, AWS, and two Yubikey ones.

Backpatch-through: master
2020-12-26 01:19:09 -05:00
Bruce Momjian 3d4843babc doc: fix SGML markup for pg_alterckey from commit 62afb42a7f
Backpatch-through: master
2020-12-26 01:10:24 -05:00
Bruce Momjian 82f8c45be5 pg_alterckey: adjust doc build and Win32 sleep/open build fails
Fix for commit 62afb42a7f.

Reported-by: Tom Lane

Discussion: https://postgr.es/m/1252111.1608953815@sss.pgh.pa.us

Backpatch-through: master
2020-12-25 22:47:16 -05:00
Bruce Momjian 7705f8ca03 Fix function call typo in frontend Win32 code, commit 978f869b99
Reported-by: buildfarm member walleye

Backpatch-through: master
2020-12-25 20:49:50 -05:00
Bruce Momjian 300e430c76 Allow ssl_passphrase_command to prompt the terminal
Previously the command could not access the terminal for a passphrase.

Backpatch-through: master
2020-12-25 20:41:06 -05:00
Bruce Momjian 62afb42a7f Add pg_alterckey utility to change the cluster key
This can change the key that encrypts the data encryption keys used for
cluster file encryption.

Discussion: https://postgr.es/m/20201202213814.GG20285@momjian.us

Backpatch-through: master
2020-12-25 20:24:53 -05:00
Bruce Momjian f234899353 remove missing reference to crypto test from patch 978f869b99
Reported-by: Tom Lane

Discussion: https://postgr.es/m/1205031.1608925990@sss.pgh.pa.us

Backpatch-through: master
2020-12-25 15:13:25 -05:00
Tom Lane 0848cf4f55 Really fix the dummy implementations in cipher.c.
945083b2f wasn't enough to silence compiler warnings.
2020-12-25 14:45:24 -05:00
Bruce Momjian 8e59813e22 fix no-return function call in cipher.c from commit 978f869b99
Reported-by: buildfarm member sifaka

Backpatch-through: master
2020-12-25 14:40:46 -05:00
Bruce Momjian 26d60f2a6c fixes docs and missing initdb help option for commit 978f869b99
Reported-by: Erik Rijkers

Discussion: https://postgr.es/m/a27e7bb60fc4c4a1fe960f7b055ba822@xs4all.nl

Backpatch-through: master
2020-12-25 14:00:22 -05:00
Noah Misch 08db7c63f3 Invalidate acl.c caches when pg_authid changes.
This makes existing sessions reflect "ALTER ROLE ... [NO]INHERIT" as
quickly as they have been reflecting "GRANT role_name".  Back-patch to
9.5 (all supported versions).

Reviewed by Nathan Bossart.

Discussion: https://postgr.es/m/20201221095028.GB3777719@rfd.leadboat.com
2020-12-25 10:41:59 -08:00
Bruce Momjian e35b2bad1a remove uint128 requirement from patch 978f869b99 (CFE)
Used char[16] instead.

Reported-by: buildfarm member florican

Backpatch-through: master
2020-12-25 11:35:59 -05:00
Bruce Momjian 945083b2f7 Fix return value and const declaration from commit 978f869b99
This fixes the non-OpenSSL compile case.

Reported-by: buildfarm member sifaka

Backpatch-through: master
2020-12-25 11:00:32 -05:00
Bruce Momjian 978f869b99 Add key management system
This adds a key management system that stores (currently) two data
encryption keys of length 128, 192, or 256 bits.  The data keys are
AES256 encrypted using a key encryption key, and validated via GCM
cipher mode.  A command to obtain the key encryption key must be
specified at initdb time, and will be run at every database server
start.  New parameters allow a file descriptor open to the terminal to
be passed.  pg_upgrade support has also been added.

Discussion: https://postgr.es/m/CA+fd4k7q5o6Nc_AaX6BcYM9yqTbC6_pnH-6nSD=54Zp6NBQTCQ@mail.gmail.com
Discussion: https://postgr.es/m/20201202213814.GG20285@momjian.us

Author: Masahiko Sawada, me, Stephen Frost
2020-12-25 10:19:44 -05:00
Tom Lane 5c31afc49d Avoid time-of-day-dependent failure in log rotation test.
Buildfarm members pogona and petalura have shown a failure when
pg_ctl/t/004_logrotate.pl starts just before local midnight.
The default rotate-at-midnight behavior occurs just before the
Perl script examines current_logfiles, so it figures that the
rotation it's already requested has occurred ... but in reality,
that rotation happens just after it looks, so the expected new
log data goes into a different file than the one it's examining.

In HEAD, src/test/kerberos/t/001_auth.pl has acquired similar code
that evidently has a related failure mode.  Besides being quite new,
few buildfarm critters run that test, so it's unsurprising that
we've not yet seen a failure there.

Fix both cases by setting log_rotation_age = 0 so that no time-based
rotation can occur.  Also absorb 004_logrotate.pl's decision to
set lc_messages = 'C' into the kerberos test, in hopes that it will
work in non-English prevailing locales.

Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=pogona&dt=2020-12-24%2022%3A10%3A04
Report: https://buildfarm.postgresql.org/cgi-bin/show_log.pl?nm=petalura&dt=2020-02-01%2022%3A20%3A04
2020-12-24 21:37:46 -05:00
Bruce Momjian 558a6e8e21 revert removal of hex_decode() from ecpg from commit c3826f831e
ecpglib on certain platforms can't handle the pg_log_fatal calls from
libraries.  This was reported by the buildfarm.  It needs a refactoring
and return value change if it is later removed.

Backpatch-through: master
2020-12-24 18:21:37 -05:00
Bruce Momjian c3826f831e move hex_decode() to /common so it can be called from frontend
This allows removal of a copy of hex_decode() from ecpg, and will be
used by the soon-to-be added pg_alterckey command.

Backpatch-through: master
2020-12-24 17:25:48 -05:00
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
Tom Lane 7e784d1dc1 Improve client error messages for immediate-stop situations.
Up to now, if the DBA issued "pg_ctl stop -m immediate", the message
sent to clients was the same as for a crash-and-restart situation.
This is confusing, not least because the message claims that the
database will soon be up again, something we have no business
predicting.

Improve things so that we can generate distinct messages for the two
cases (and also recognize an ad-hoc SIGQUIT, should somebody try that).
To do that, add a field to pmsignal.c's shared memory data structure
that the postmaster sets just before broadcasting SIGQUIT to its
children.  No interlocking seems to be necessary; the intervening
signal-sending and signal-receipt should sufficiently serialize accesses
to the field.  Hence, this isn't any riskier than the existing usages
of pmsignal.c.

We might in future extend this idea to improve other
postmaster-to-children signal scenarios, although none of them
currently seem to be as badly overloaded as SIGQUIT.

Discussion: https://postgr.es/m/559291.1608587013@sss.pgh.pa.us
2020-12-24 12:58:32 -05:00
Michael Paquier 90fbf7c57d Fix typos and grammar in docs and comments
This fixes several areas of the documentation and some comments in
matters of style, grammar, or even format.

Author: Justin Pryzby
Discussion: https://postgr.es/m/20201222041153.GK30237@telsasoft.com
2020-12-24 17:05:49 +09:00
Bruce Momjian 6ecf488d91 dummy commit 2020-12-23 09:33:20 -05:00