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43518 commits

Author SHA1 Message Date
Tom Lane
85feb77aa0 Assume wcstombs(), towlower(), and sibling functions are always present.
These functions are required by SUS v2, which is our minimum baseline
for Unix platforms, and are present on all interesting Windows versions
as well.  Even our oldest buildfarm members have them.  Thus, we were not
testing the "!USE_WIDE_UPPER_LOWER" code paths, which explains why the bug
fixed in commit e6023ee7f escaped detection.  Per discussion, there seems
to be no more real-world value in maintaining this option.  Hence, remove
the configure-time tests for wcstombs() and towlower(), remove the
USE_WIDE_UPPER_LOWER symbol, and remove all the !USE_WIDE_UPPER_LOWER code.
There's not actually all that much of the latter, but simplifying the #if
nests is a win in itself.

Discussion: https://postgr.es/m/20170921052928.GA188913@rfd.leadboat.com
2017-09-22 11:00:58 -04:00
Peter Eisentraut
e6023ee7fa Fix build with !USE_WIDE_UPPER_LOWER
The placement of the ifdef blocks in formatting.c was pretty bogus, so
the code failed to compile if USE_WIDE_UPPER_LOWER was not defined.

Reported-by: Peter Geoghegan <pg@bowt.ie>
Reported-by: Noah Misch <noah@leadboat.com>
2017-09-22 09:26:38 -04:00
Alvaro Herrera
885cab5811 Document further existing locks as wait events
Reported-by: Jeremy Schneider
Author: Michael Paquier
Discussion: https://postgr.es/m/CA+fnDAZaPCwfY8Lp-pfLnUGFAXRu1VfLyRgdup-L-kwcBj8MqQ@mail.gmail.com
2017-09-22 13:37:28 +02:00
Tom Lane
47f849a3c9 Sync our copy of the timezone library with IANA tzcode master.
This patch absorbs a few unreleased fixes in the IANA code.
It corresponds to commit 2d8b944c1cec0808ac4f7a9ee1a463c28f9cd00a
in https://github.com/eggert/tz.  Non-cosmetic changes include:

TZDEFRULESTRING is updated to match current US DST practice,
rather than what it was over ten years ago.  This only matters
for interpretation of POSIX-style zone names (e.g., "EST5EDT"),
and only if the timezone database doesn't include either an exact
match for the zone name or a "posixrules" entry.  The latter
should not be true in any current Postgres installation, but
this could possibly matter when using --with-system-tzdata.

Get rid of a nonportable use of "++var" on a bool var.
This is part of a larger fix that eliminates some vestigial
support for consecutive leap seconds, and adds checks to
the "zic" compiler that the data files do not specify that.

Remove a couple of ancient compatibility hacks.  The IANA
crew think these are obsolete, and I tend to agree.  But
perhaps our buildfarm will think different.

Back-patch to all supported branches, in line with our policy
that all branches should be using current IANA code.  Before v10,
this includes application of current pgindent rules, to avoid
whitespace problems in future back-patches.

Discussion: https://postgr.es/m/E1dsWhf-0000pT-F9@gemulon.postgresql.org
2017-09-22 00:04:29 -04:00
Tom Lane
a890432a87 Revert "Fix bool/int type confusion"
This reverts commit 0ec2e908ba.
We'll use the upstream (IANA) fix instead.
2017-09-22 00:04:29 -04:00
Andrew Dunstan
d57c7a7c50 Provide a test for variable existence in psql
"\if :{?variable_name}" will be translated to "\if TRUE" if the variable
exists and "\if FALSE" otherwise. Thus it will be possible to execute code
conditionally on the existence of the variable, regardless of its value.

Fabien Coelho, with some review by Robins Tharakan and some light text
editing by me.

Discussion: https://postgr.es/m/alpine.DEB.2.20.1708260835520.3627@lancre
2017-09-21 19:02:23 -04:00
Tom Lane
7148050105 Give a better error for duplicate entries in VACUUM/ANALYZE column list.
Previously, the code didn't think about this case and would just try to
analyze such a column twice.  That would fail at the point of inserting
the second version of the pg_statistic row, with obscure error messsages
like "duplicate key value violates unique constraint" or "tuple already
updated by self", depending on context and PG version.  We could allow
the case by ignoring duplicate column specifications, but it seems better
to reject it explicitly.

The bogus error messages seem like arguably a bug, so back-patch to
all supported versions.

Nathan Bossart, per a report from Michael Paquier, and whacked
around a bit by me.

Discussion: https://postgr.es/m/E061A8E3-5E3D-494D-94F0-E8A9B312BBFC@amazon.com
2017-09-21 18:13:11 -04:00
Andrew Dunstan
28ae524bbf Quieten warnings about unused variables
These variables are only ever written to in assertion-enabled builds,
and the latest Microsoft compilers complain about such variables in
non-assertion-enabled builds.

Apparently they don't worry so much about variables that are written to
but not read from, so most of our PG_USED_FOR_ASSERTS_ONLY variables
don't cause the problem.

Discussion: https://postgr.es/m/7800.1505950322@sss.pgh.pa.us
2017-09-21 08:41:14 -04:00
Robert Haas
9140cf8269 Associate partitioning information with each RelOptInfo.
This is not used for anything yet, but it is necessary infrastructure
for partition-wise join and for partition pruning without constraint
exclusion.

Ashutosh Bapat, reviewed by Amit Langote and with quite a few changes,
mostly cosmetic, by me.  Additional review and testing of this patch
series by Antonin Houska, Amit Khandekar, Rafia Sabih, Rajkumar
Raghuwanshi, Thomas Munro, and Dilip Kumar.

Discussion: http://postgr.es/m/CAFjFpRfneFG3H+F6BaiXemMrKF+FY-POpx3Ocy+RiH3yBmXSNw@mail.gmail.com
2017-09-20 23:39:13 -04:00
Tom Lane
7b86c2ac95 Improve dubious memory management in pg_newlocale_from_collation().
pg_newlocale_from_collation() used malloc() and strdup() directly,
which is generally not per backend coding style, and it didn't bother
to check for failure results, but would just SIGSEGV instead.  Also,
if one of the numerous error checks in the middle of the function
failed, the already-allocated memory would be leaked permanently.
Admittedly, it's not a lot of memory, but it could build up if this
function were called repeatedly for a bad collation.

The first two problems are easily cured by palloc'ing in TopMemoryContext
instead of calling libc directly.  We can fairly easily dodge the leakage
problem for the struct pg_locale_struct by filling in a temporary variable
and allocating permanent storage only once we reach the bottom of the
function.  It's harder to get rid of the potential leakage for ICU's copy
of the collcollate string, but at least that's only allocated after most
of the error checks; so live with that aspect.

Back-patch to v10 where this code came in, with one or another of the
ICU patches.
2017-09-20 13:52:36 -04:00
Tom Lane
4939488af9 Fix instability in subscription regression test.
005_encoding.pl neglected to wait for the subscriber's initial
synchronization to happen.  While we have not seen this fail in
the buildfarm, it's pretty easy to demonstrate there's an issue
by hacking logicalrep_worker_launch() to fail most of the time.

Michael Paquier

Discussion: https://postgr.es/m/27032.1505749806@sss.pgh.pa.us
2017-09-20 11:28:34 -04:00
Tom Lane
36b564c648 Fix erroneous documentation about noise word GROUP.
GRANT, REVOKE, and some allied commands allow the noise word GROUP
before a role name (cf. grantee production in gram.y).  This option
does not exist elsewhere, but it had nonetheless snuck into the
documentation for ALTER ROLE, ALTER USER, and CREATE SCHEMA.

Seems to be a copy-and-pasteo in commit 31eae6028, which did expand the
syntax choices here, but not in that way.  Back-patch to 9.5 where that
came in.

Discussion: https://postgr.es/m/20170916123750.8885.66941@wrigleys.postgresql.org
2017-09-20 11:10:36 -04:00
Robert Haas
57eebca03a Fix create_lateral_join_info to handle dead relations properly.
Commit 0a480502b0 broke it.

Report by Andreas Seltenreich.  Fix by Ashutosh Bapat.

Discussion: http://postgr.es/m/874ls2vrnx.fsf@ansel.ydns.eu
2017-09-20 10:20:10 -04:00
Robert Haas
7f3a3312ab Fix typo.
Thomas Munro

Discussion: http://postgr.es/m/CAEepm=2j-HAgnBUrAazwS0ry7Z_ihk+d7g+Ye3u99+6WbiGt_Q@mail.gmail.com
2017-09-20 10:07:53 -04:00
Bruce Momjian
00210e3fb9 docs: re-add instructions on setting wal_level for rsync use
This step was erroneously removed four days ago by me.

Reported-by: Magnus via IM

Backpatch-through: 9.5
2017-09-20 09:36:19 -04:00
Peter Eisentraut
d42294fc00 Fix compiler warning
from gcc-7 -Wformat-truncation (via -Wall)
2017-09-20 09:03:04 -04:00
Peter Eisentraut
be87b70b61 Sync process names between ps and pg_stat_activity
Remove gratuitous differences in the process names shown in
pg_stat_activity.backend_type and the ps output.

Reviewed-by: Takayuki Tsunakawa <tsunakawa.takay@jp.fujitsu.com>
2017-09-20 08:59:03 -04:00
Magnus Hagander
2c74e6c1dc Mention need for --no-inc-recursive in rsync command
Since rsync 3.0.0 (released in 2008), the default way to enumerate
changes was changed in a way that makes it less likely that the hardlink
sync mode works. Since the whole point of the documented procedure is
for the hardlinks to work, change our docs to suggest using the
backwards compatibility switch.
2017-09-20 14:09:05 +02:00
Andres Freund
fc49e24fa6 Make WAL segment size configurable at initdb time.
For performance reasons a larger segment size than the default 16MB
can be useful. A larger segment size has two main benefits: Firstly,
in setups using archiving, it makes it easier to write scripts that
can keep up with higher amounts of WAL, secondly, the WAL has to be
written and synced to disk less frequently.

But at the same time large segment size are disadvantageous for
smaller databases. So far the segment size had to be configured at
compile time, often making it unrealistic to choose one fitting to a
particularly load. Therefore change it to a initdb time setting.

This includes a breaking changes to the xlogreader.h API, which now
requires the current segment size to be configured.  For that and
similar reasons a number of binaries had to be taught how to recognize
the current segment size.

Author: Beena Emerson, editorialized by Andres Freund
Reviewed-By: Andres Freund, David Steele, Kuntal Ghosh, Michael
    Paquier, Peter Eisentraut, Robert Hass, Tushar Ahuja
Discussion: https://postgr.es/m/CAOG9ApEAcQ--1ieKbhFzXSQPw_YLmepaa4hNdnY5+ZULpt81Mw@mail.gmail.com
2017-09-19 22:03:48 -07:00
Andres Freund
5ada1fcd0c Accept that server might not be able to send error in crash recovery test.
As it turns out we can't rely that the script's monitoring session is
terminated with a proper error by the server, because the session
might be terminated while already trying to send data.

Also improve robustness and error reporting facilities of the test,
developed while debugging this issue.

Discussion: https://postgr.es/m/20170920020038.kllxgilo7xzwmtto@alap3.anarazel.de
2017-09-19 21:37:24 -07:00
Tom Lane
2d484f9b05 Remove no-op GiST support functions in the core GiST opclasses.
The preceding patch allowed us to remove useless GiST support functions.
This patch actually does that for all the no-op cases in the core GiST
code.  This buys us whatever performance gain is to be had, and more
importantly exercises the preceding patch.

There remain no-op functions in the contrib GiST opclasses, but those
will take more work to remove.

Discussion: https://postgr.es/m/CAJEAwVELVx9gYscpE=Be6iJxvdW5unZ_LkcAaVNSeOwvdwtD=A@mail.gmail.com
2017-09-19 23:32:59 -04:00
Tom Lane
d3a4f89d8a Allow no-op GiST support functions to be omitted.
There are common use-cases in which the compress and/or decompress
functions can be omitted, with the result being that we make no
data transformation when storing or retrieving index values.
Previously, you had to provide a no-op function anyway, but this
patch allows such opclass support functions to be omitted.

Furthermore, if the compress function is omitted, then the core code
knows that the stored representation is the same as the original data.
This means we can allow index-only scans without requiring a fetch
function to be provided either.  Previously you had to provide a
no-op fetch function if you wanted IOS to work.

This reportedly provides a small performance benefit in such cases,
but IMO the real reason for doing it is just to reduce the amount of
useless boilerplate code that has to be written for GiST opclasses.

Andrey Borodin, reviewed by Dmitriy Sarafannikov

Discussion: https://postgr.es/m/CAJEAwVELVx9gYscpE=Be6iJxvdW5unZ_LkcAaVNSeOwvdwtD=A@mail.gmail.com
2017-09-19 23:32:59 -04:00
Andres Freund
896537f078 s/NULL byte/NUL byte/ in comment refering to C string terminator.
Reported-By: Robert Haas
Discussion: https://postgr.es/m/CA+Tgmoa+YBvWgFST2NVoeXjVSohEpK=vqnVCsoCkhTVVxfLcVQ@mail.gmail.com
2017-09-19 16:41:07 -07:00
Peter Eisentraut
f41e56c76e Add basic TAP test setup for pg_upgrade
The plan is to convert the current pg_upgrade test to the TAP
framework.  This commit just puts a basic TAP test in place so that we
can see how the build farm behaves, since the build farm client has some
special knowledge of the pg_upgrade tests.

Author: Michael Paquier <michael.paquier@gmail.com>
2017-09-19 18:51:25 -04:00
Andres Freund
71edbb6f66 Avoid use of non-portable strnlen() in pgstat_clip_activity().
The use of strnlen rather than strlen was just paranoia. Instead of
giving up on the paranoia, just implement the safeguard
differently. And add a comment explaining why we're careful.

Author: Andres Freund
Discussion: https://postgr.es/m/E1duOkJ-0001Mc-U5@gemulon.postgresql.org
2017-09-19 14:25:47 -07:00
Andres Freund
54b6cd589a Speedup pgstat_report_activity by moving mb-aware truncation to read side.
Previously multi-byte aware truncation was done on every
pgstat_report_activity() call - proving to be a bottleneck for
workloads with long query strings that execute quickly.

Instead move the truncation to the read side, which commonly is
executed far less frequently. That's possible because all server
encodings allow to determine the length of a multi-byte string from
the first byte.

Rename PgBackendStatus.st_activity to st_activity_raw so existing
extension users of the field break - their code has to be adjusted to
use pgstat_clip_activity().

Author: Andres Freund
Tested-By: Khuntal Ghosh
Reviewed-By: Robert Haas, Tom Lane
Discussion: https://postgr.es/m/20170912071948.pa7igbpkkkviecpz@alap3.anarazel.de
2017-09-19 12:51:14 -07:00
Andrew Dunstan
d1687c6926 Disable multi-byte citext tests
This reverts commit 890faaf1 which attempted unsuccessfully to deal with
the problem, and instead just comments out these tests like other similar
tests elsewhere in the script.
2017-09-19 15:31:37 -04:00
Tom Lane
ed22fb8b00 Cache datatype-output-function lookup info across calls of concat().
Testing indicates this can save a third to a half of the runtime
of the function.

Pavel Stehule, reviewed by Alexander Kuzmenkov

Discussion: https://postgr.es/m/CAFj8pRAT62pRgjoHbgTfJUc2uLmeQ4saUj+yVJAEZUiMwNCmdg@mail.gmail.com
2017-09-19 15:09:38 -04:00
Andrew Dunstan
890faaf195 Set client encoding to UTF8 for the citext regression script
Problem introduced with non-ascii characters in commit f246499764
and discovered on various buildfarm animals.
2017-09-19 14:51:51 -04:00
Andres Freund
1910353675 Make new crash restart test a bit more robust.
Add timeouts in case psql doesn't deliver the expected output, and try
to cause the monitoring psql to be fully connected to a backend.  This
isn't necessarily everything needed, but at least the timeouts should
reduce the pain for buildfarm owners.

Author: Andres Freund
Reported-By: Tom Lane, BF animals prairiedog and calliphoridae
Discussion: https://postgr.es/m/E1du6ZT-00043I-91@gemulon.postgresql.org
2017-09-19 10:39:52 -07:00
Bruce Momjian
d61f5bb7c4 doc: add example of % substitution for connection URIs
Reported-by: Zhou Digoal

Discussion: https://postgr.es/m/20170912133722.25637.91@wrigleys.postgresql.org

Backpatch-through: 10
2017-09-19 12:23:18 -04:00
Andrew Dunstan
f246499764 Add citext_pattern_ops for citext contrib module
This is similar to text_pattern_ops.

Alexey Chernyshov, reviewed by Jacob Champion.
2017-09-19 08:31:45 -04:00
Andres Freund
f8e5f156b3 Rearm statement_timeout after each executed query.
Previously statement_timeout, in the extended protocol, affected all
messages till a Sync message.  For clients that pipeline/batch query
execution that's problematic.

Instead disable timeout after each Execute message, and enable, if
necessary, the timer in start_xact_command(). As that's done only for
Execute and not Parse / Bind, pipelining the latter two could still
cause undesirable timeouts. But a survey of protocol implementations
shows that all drivers issue Sync messages when preparing, and adding
timeout rearming to both is fairly expensive for the common parse /
bind / execute sequence.

Author: Tatsuo Ishii, editorialized by Andres Freund
Reviewed-By: Takayuki Tsunakawa, Andres Freund
Discussion: https://postgr.es/m/20170222.115044.1665674502985097185.t-ishii@sraoss.co.jp
2017-09-18 19:36:44 -07:00
Andres Freund
0fb9e4ace5 Fix uninitialized variable in dshash.c.
A bugfix for commit 8c0d7bafad.  The code
would have crashed if hashtable->size_log2 ever had the same value as
hashtable->control->size_log2 by coincidence.

Per Valgrind.

Author: Thomas Munro
Reported-By: Tomas Vondra
Discussion: https://postgr.es/m/e72fb33c-4f31-f276-e972-263d9b59554d%402ndquadrant.com
2017-09-18 17:43:37 -07:00
Andres Freund
a1924a4ea2 Add test for postmaster crash restarts.
Given that I managed to break this...  We probably should extend the
tests to also cover other sub-processes dying, but that's something
for later.

Author: Andres Freund
Discussion: https://postgr.es/m/20170917080752.rcmihzfmgbeuqjk2@alap3.anarazel.de
2017-09-18 17:25:53 -07:00
Andres Freund
ec9e05b3c3 Fix crash restart bug introduced in 8356753c21.
The bug was caused by not re-reading the control file during crash
recovery restarts, which lead to an attempt to pfree() shared memory
contents. The fix is to re-read the control file, which seems good
anyway.

It's unclear as of this moment, whether we want to keep the
refactoring introduced in the commit referenced above, or come up with
an alternative approach. But fixing the bug in the mean time seems
like a good idea regardless.

A followup commit will introduce regression test coverage for crash
restarts.

Reported-By: Tom Lane
Discussion: https://postgr.es/m/14134.1505572349@sss.pgh.pa.us
2017-09-18 17:25:49 -07:00
Tom Lane
eb5c404b17 Minor code-cleanliness improvements for btree.
Make the btree page-flags test macros (P_ISLEAF and friends) return clean
boolean values, rather than values that might not fit in a bool.  Use them
in a few places that were randomly referencing the flag bits directly.

In passing, change access/nbtree/'s only direct use of BUFFER_LOCK_SHARE to
BT_READ.  (Some think we should go the other way, but as long as we have
BT_READ/BT_WRITE, let's use them consistently.)

Masahiko Sawada, reviewed by Doug Doole

Discussion: https://postgr.es/m/CAD21AoBmWPeN=WBB5Jvyz_Nt3rmW1ebUyAnk3ZbJP3RMXALJog@mail.gmail.com
2017-09-18 16:36:28 -04:00
Tom Lane
66917bfaa7 Make ExplainOpenGroup and ExplainCloseGroup public.
Extensions with custom plan nodes might like to use these in their
EXPLAIN output.

Hadi Moshayedi

Discussion: https://postgr.es/m/CA+_kT_dU-rHCN0u6pjA6bN5CZniMfD=-wVqPY4QLrKUY_uJq5w@mail.gmail.com
2017-09-18 16:01:16 -04:00
Tom Lane
4bd1994650 Make DatumGetFoo/PG_GETARG_FOO/PG_RETURN_FOO macro names more consistent.
By project convention, these names should include "P" when dealing with a
pointer type; that is, if the result of a GETARG macro is of type FOO *,
it should be called PG_GETARG_FOO_P not just PG_GETARG_FOO.  Some newer
types such as JSONB and ranges had not followed the convention, and a
number of contrib modules hadn't gotten that memo either.  Rename the
offending macros to improve consistency.

In passing, fix a few places that thought PG_DETOAST_DATUM() returns
a Datum; it does not, it returns "struct varlena *".  Applying
DatumGetPointer to that happens not to cause any bad effects today,
but it's formally wrong.  Also, adjust an ltree macro that was designed
without any thought for what pgindent would do with it.

This is all cosmetic and shouldn't have any impact on generated code.

Mark Dilger, some further tweaks by me

Discussion: https://postgr.es/m/EA5676F4-766F-4F38-8348-ECC7DB427C6A@gmail.com
2017-09-18 15:21:23 -04:00
Tom Lane
3e1683d37e Fix, or at least ameliorate, bugs in logicalrep_worker_launch().
If we failed to get a background worker slot, the code just walked
away from the logicalrep-worker slot it already had, leaving that
looking like the worker is still starting up.  This led to an indefinite
hang in subscription startup, as reported by Thomas Munro.  We must
release the slot on failure.

Also fix a thinko: we must capture the worker slot's generation before
releasing LogicalRepWorkerLock the first time, else testing to see if
it's changed is pretty meaningless.

BTW, the CHECK_FOR_INTERRUPTS() in WaitForReplicationWorkerAttach is a
ticking time bomb, even without considering the possibility of elog(ERROR)
in one of the other functions it calls.  Really, this entire business needs
a redesign with some actual thought about error recovery.  But for now
I'm just band-aiding the case observed in testing.

Back-patch to v10 where this code was added.

Discussion: https://postgr.es/m/CAEepm=2bP3TBMFBArP6o20AZaRduWjMnjCjt22hSdnA-EvrtCw@mail.gmail.com
2017-09-18 11:39:55 -04:00
Peter Eisentraut
4b17c89429 Update some dead external links in the documentation 2017-09-18 11:09:15 -04:00
Peter Eisentraut
d31892e210 Remove dead external links from documentation 2017-09-18 10:41:48 -04:00
Peter Eisentraut
8edacab209 Fix DROP SUBSCRIPTION hang
When ALTER SUBSCRIPTION DISABLE is run in the same transaction before
DROP SUBSCRIPTION, the latter will hang because workers will still be
running, not having seen the DISABLE committed, and DROP SUBSCRIPTION
will wait until the workers have vacated the replication origin slots.

Previously, DROP SUBSCRIPTION killed the logical replication workers
immediately only if it was going to drop the replication slot, otherwise
it scheduled the worker killing for the end of the transaction, as a
result of 7e174fa793.  This, however,
causes the present problem.  To fix, kill the workers immediately in all
cases.  This covers all cases: A subscription that doesn't have a
replication slot must be disabled.  It was either disabled in the same
transaction, or it was already disabled before the current transaction,
but then there shouldn't be any workers left and this won't make a
difference.

Reported-by: Arseny Sher <a.sher@postgrespro.ru>
Discussion: https://www.postgresql.org/message-id/flat/87mv6av84w.fsf%40ars-thinkpad
2017-09-17 22:00:23 -04:00
Tom Lane
68ab9acd85 Doc: update v10 release notes through today.
Add item about number of times statement-level triggers will be fired.
Rearrange the compatibility items into (what seems to me) a less
random ordering.
2017-09-17 17:04:21 -04:00
Tom Lane
6f44fe7f12 Allow rel_is_distinct_for() to look through RelabelType below OpExpr.
This lets it do the right thing for, eg, varchar columns.
Back-patch to 9.5 where this logic appeared.

David Rowley, per report from Kim Rose Carlsen

Discussion: https://postgr.es/m/VI1PR05MB17091F9A9876528055D6A827C76D0@VI1PR05MB1709.eurprd05.prod.outlook.com
2017-09-17 15:28:51 -04:00
Tom Lane
27c6619e9c Fix possible dangling pointer dereference in trigger.c.
AfterTriggerEndQuery correctly notes that the query_stack could get
repalloc'd during a trigger firing, but it nonetheless passes the address
of a query_stack entry to afterTriggerInvokeEvents, so that if such a
repalloc occurs, afterTriggerInvokeEvents is already working with an
obsolete dangling pointer while it scans the rest of the events.  Oops.
The only code at risk is its "delete_ok" cleanup code, so we can
prevent unsafe behavior by passing delete_ok = false instead of true.

However, that could have a significant performance penalty, because the
point of passing delete_ok = true is to not have to re-scan possibly
a large number of dead trigger events on the next time through the loop.
There's more than one way to skin that cat, though.  What we can do is
delete all the "chunks" in the event list except the last one, since
we know all events in them must be dead.  Deleting the chunks is work
we'd have had to do later in AfterTriggerEndQuery anyway, and it ends
up saving rescanning of just about the same events we'd have gotten
rid of with delete_ok = true.

In v10 and HEAD, we also have to be careful to mop up any per-table
after_trig_events pointers that would become dangling.  This is slightly
annoying, but I don't think that normal use-cases will traverse this code
path often enough for it to be a performance problem.

It's pretty hard to hit this in practice because of the unlikelihood
of the query_stack getting resized at just the wrong time.  Nonetheless,
it's definitely a live bug of ancient standing, so back-patch to all
supported branches.

Discussion: https://postgr.es/m/2891.1505419542@sss.pgh.pa.us
2017-09-17 14:50:01 -04:00
Tom Lane
fd31f9f033 Ensure that BEFORE STATEMENT triggers fire the right number of times.
Commit 0f79440fb introduced mechanism to keep AFTER STATEMENT triggers
from firing more than once per statement, which was formerly possible
if more than one FK enforcement action had to be applied to a given
table.  Add a similar mechanism for BEFORE STATEMENT triggers, so that
we don't have the unexpected situation of firing BEFORE STATEMENT
triggers more often than AFTER STATEMENT.

As with the previous patch, back-patch to v10.

Discussion: https://postgr.es/m/22315.1505584992@sss.pgh.pa.us
2017-09-17 12:16:38 -04:00
Tom Lane
cad22075bc Fix bogus size calculation introduced by commit cc5f81366.
The elements of RecordCacheArray are TupleDesc, not TupleDesc *.
Those are actually the same size, so that this error is harmless,
but it's still wrong --- and it might bite us someday, if TupleDesc
ever became a struct, say.

Per Coverity.
2017-09-17 11:35:27 -04:00
Tom Lane
936df5ba80 Doc: add example of transition table use in a trigger.
I noticed that there were exactly no complete examples of use of
a transition table in a trigger function, and no clear description
of just how you'd do it either.  Improve that.
2017-09-16 15:31:26 -04:00
Tom Lane
0f79440fb0 Fix SQL-spec incompatibilities in new transition table feature.
The standard says that all changes of the same kind (insert, update, or
delete) caused in one table by a single SQL statement should be reported
in a single transition table; and by that, they mean to include foreign key
enforcement actions cascading from the statement's direct effects.  It's
also reasonable to conclude that if the standard had wCTEs, they would say
that effects of wCTEs applying to the same table as each other or the outer
statement should be merged into one transition table.  We weren't doing it
like that.

Hence, arrange to merge tuples from multiple update actions into a single
transition table as much as we can.  There is a problem, which is that if
the firing of FK enforcement triggers and after-row triggers with
transition tables is interspersed, we might need to report more tuples
after some triggers have already seen the transition table.  It seems like
a bad idea for the transition table to be mutable between trigger calls.
There's no good way around this without a major redesign of the FK logic,
so for now, resolve it by opening a new transition table each time this
happens.

Also, ensure that AFTER STATEMENT triggers fire just once per statement,
or once per transition table when we're forced to make more than one.
Previous versions of Postgres have allowed each FK enforcement query
to cause an additional firing of the AFTER STATEMENT triggers for the
referencing table, but that's certainly not per spec.  (We're still
doing multiple firings of BEFORE STATEMENT triggers, though; is that
something worth changing?)

Also, forbid using transition tables with column-specific UPDATE triggers.
The spec requires such transition tables to show only the tuples for which
the UPDATE trigger would have fired, which means maintaining multiple
transition tables or else somehow filtering the contents at readout.
Maybe someday we'll bother to support that option, but it looks like a
lot of trouble for a marginal feature.

The transition tables are now managed by the AfterTriggers data structures,
rather than being directly the responsibility of ModifyTable nodes.  This
removes a subtransaction-lifespan memory leak introduced by my previous
band-aid patch 3c4359521.

In passing, refactor the AfterTriggers data structures to reduce the
management overhead for them, by using arrays of structs rather than
several parallel arrays for per-query-level and per-subtransaction state.

I failed to resist the temptation to do some copy-editing on the SGML
docs about triggers, above and beyond merely documenting the effects
of this patch.

Back-patch to v10, because we don't want the semantics of transition
tables to change post-release.

Patch by me, with help and review from Thomas Munro.

Discussion: https://postgr.es/m/20170909064853.25630.12825@wrigleys.postgresql.org
2017-09-16 13:20:36 -04:00