SQL "SET search_path = 'pg_catalog, pg_temp'" is silently equivalent to
"SET search_path = pg_temp, pg_catalog, "pg_catalog, pg_temp"" instead
of the intended "SET search_path = pg_catalog, pg_temp". (The intent
was a two-element search path. With the single quotes, it instead
specifies one element with a comma and a space in the middle of the
element.) In addition to the SET statement, this affects SET clauses of
CREATE FUNCTION, ALTER ROLE, and ALTER DATABASE. It does not affect the
set_config() SQL function.
Though the documentation did not show an insecure command, remove single
quotes that could entice a reader to write an insecure command.
Back-patch to v13 (all supported versions).
Reported-by: Sven Klemm <sven@timescale.com>
Author: Sven Klemm <sven@timescale.com>
Backpatch-through: 13
The variable is a bit magical in how it requires "postgresql" or
"pgsql" to be part of the path, and files end up in its "share" and
"lib" subdirectories. So mention all that and show an example of
setting "extension_control_path" and "dynamic_library_path" to use
those locations.
Author: David E. Wheeler <david@justatheory.com>
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Reviewed-by: Christoph Berg <myon@debian.org>
Discussion: https://www.postgresql.org/message-id/6B5BF07B-8A21-48E3-858C-1DC22F3A28B4@justatheory.com
The additional packaging footprint of the OAuth Curl dependency, as well
as the existence of libcurl in the address space even if OAuth isn't
ever used by a client, has raised some concerns. Split off this
dependency into a separate loadable module called libpq-oauth.
When configured using --with-libcurl, libpq.so searches for this new
module via dlopen(). End users may choose not to install the libpq-oauth
module, in which case the default flow is disabled.
For static applications using libpq.a, the libpq-oauth staticlib is a
mandatory link-time dependency for --with-libcurl builds. libpq.pc has
been updated accordingly.
The default flow relies on some libpq internals. Some of these can be
safely duplicated (such as the SIGPIPE handlers), but others need to be
shared between libpq and libpq-oauth for thread-safety. To avoid
exporting these internals to all libpq clients forever, these
dependencies are instead injected from the libpq side via an
initialization function. This also lets libpq communicate the offsets of
PGconn struct members to libpq-oauth, so that we can function without
crashing if the module on the search path came from a different build of
Postgres. (A minor-version upgrade could swap the libpq-oauth module out
from under a long-running libpq client before it does its first load of
the OAuth flow.)
This ABI is considered "private". The module has no SONAME or version
symlinks, and it's named libpq-oauth-<major>.so to avoid mixing and
matching across Postgres versions. (Future improvements may promote this
"OAuth flow plugin" to a first-class concept, at which point we would
need a public API to replace this anyway.)
Additionally, NLS support for error messages in b3f0be788a was
incomplete, because the new error macros weren't being scanned by
xgettext. Fix that now.
Per request from Tom Lane and Bruce Momjian. Based on an initial patch
by Daniel Gustafsson, who also contributed docs changes. The "bare"
dlopen() concept came from Thomas Munro. Many people reviewed the design
and implementation; thank you!
Co-authored-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Christoph Berg <myon@debian.org>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Jelte Fennema-Nio <postgres@jeltef.nl>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Wolfgang Walther <walther@technowledgy.de>
Discussion: https://postgr.es/m/641687.1742360249%40sss.pgh.pa.us
Add a documentation warning to ts_headline() pointing out that, when
working with untrusted input documents, the output is not guaranteed
to be safe for direct inclusion in web pages. This is because, while
it does remove some XML tags from the input, it doesn't remove all
HTML markup, and so the result may be unsafe (e.g., it might permit
XSS attacks).
To guard against that, all HTML markup should be removed from the
input, making it plain text, or the output should be passed through an
HTML sanitizer.
In addition, document precisely what the default text search parser
recognises as valid XML tags, since that's what determines which XML
tags ts_headline() will remove.
Reported-by: Richard Neill <richard.neill@telos.digital>
Author: Dean Rasheed <dean.a.rasheed@gmail.com>
Reviewed-by: Noah Misch <noah@leadboat.com>
Backpatch-through: 13
Further improvement for commit 11bd8318602. That commit confused
identity and generated columns; fix that. Also, virtual generated
columns have since been added; add more details about that. Also some
small rewordings and reformattings to further improve clarity.
Reviewed-by: Robert Treat <rob@xzilla.net>
Discussion: https://postgr.es/m/00e6eb5f5c793b8ef722252c7a519c9a@oss.nttdata.com
30a6ed0ce4b has added four attributes to pg_stat_all_tables to track the
cumulative time spent in [auto]vacuum and [auto]analyze. It was not
mentioned that the vacuum cost-based delays are included in these
numbers, which could be confusing now that the delays are included in
the vacuum progress view (bb8dff9995f2).
This commit adds an extra note about this matter.
Reported-by: Magnus Hagander <magnus@hagander.net>
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/CABUevEz9v1ZNToPyD98JnWDGZgG=SmPZKkSNzU9hXQ-nGTQF0g@mail.gmail.com
Since pg_upgrade does not transfer the cumulative statistics used
to trigger autovacuum and autoanalyze, the server may take much
longer than expected to process them post-upgrade. Currently, we
recommend analyzing only relations for which optimizer statistics
were not transferred by using the --analyze-in-stages and
--missing-stats-only options. This commit appends another
recommendation to analyze all relations to update the relevant
cumulative statistics by using the --analyze-only option. This is
similar to the recommendation for pg_stat_reset().
Reported-by: Christoph Berg <myon@debian.org>
Reviewed-by: Christoph Berg <myon@debian.org>
Discussion: https://postgr.es/m/aAfxfKC82B9NvJDj%40msg.df7cb.de
The current ordering strategy for these pages is to list the short
options in alphabetical order followed by the long options in
alphabetical order. If an option has both a short variant and a
long variant, the short variant takes precedence. This commit
moves a few recently added options to match this style. We should
probably adjust all pages and --help output to list the long and
short options in one combined alphabetical list (with the long
variants taking precedence), but that is a much larger change, so
it is left as a future exercise.
Oversights in commits a5cf808be5, 1fd1bd8710, and bde2fb797a.
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/aBFBtsltgu3-IU1d%40nathan
This reverts commit 38da053463bef32adf563ddee5277d16d2b6c5af, which
attempted to preserve our ability to start with only 60 semaphores.
Subsequent changes (particularly 55b454d0e) have put that idea pretty
much permanently out of reach: people wishing to use Postgres v18 on
OpenBSD or NetBSD will have no choice but to increase those platforms'
default values of SEMMNI and SEMMNS.
Hence, revert 38da05346's changes in SEMAS_PER_SET and the minimum
tested value of max_connections. Adjust a comment from the subsequent
patch 6d0154196, and tweak the wording in runtime.sgml to make it
clear that changing SEMMNI/SEMMNS is no longer even a little bit
optional on these platforms.
Although 38da05346 was later back-patched into v17, leave that branch
alone: it's still capable of starting with 60 semaphores, and there's
no reason to break that.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Nathan Bossart <nathandbossart@gmail.com>
Discussion: https://postgr.es/m/E1tuZNv-0037Gs-34@gemulon.postgresql.org
Discussion: https://postgr.es/m/1052019.1745947915@sss.pgh.pa.us
Python 3.2 is no longer tested by the buildfarm, and there are only a
handful of buildfarm animals running versions older than 3.6, which
itself went end-of-life in 2021. Python 3.6.8 is the default version
shipped in RHEL8, so that seems like a reasonable baseline for PG18.
Now that we use the Python Limited API as of 0793ab810, older versions
of Python should continue functioning for users of PL/Python in
particular, so soften the language from "required" to "supported".
Wording by Tom Lane. Separate from the review of the patch itself,
several people provided input on the choice of cutoff: Christoph Berg,
Devrim Gündüz, Florents Tselai, Jelte Fennema-Nio, and Renan Alves
Fonseca. Thank you!
Suggested-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/16098.1745079444%40sss.pgh.pa.us
Previously, config.sgml included secondary index terms for
max_replication_slots and max_active_replication_origins. These are
no longer necessary, as each parameter now has a single distinct index entry.
The secondary index terms were originally useful because
max_active_replication_origins was part of max_replication_slots,
and separate index entries helped users locate each setting. However,
commit 04ff636cbce split them into independent parameters,
making the secondary terms redundant.
This commit removes the unnecessary secondary index entries to
simplify the documentation.
Author: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: Euler Taveira <euler@eulerto.com>
Reviewed-by: Robert Treat <rob@xzilla.net>
Discussion: https://postgr.es/m/e825e7a7-4877-441d-93c1-25377db36c31@oss.nttdata.com
All the injection points used in the tree have relied on an implied
rule: their names should be made of lower-case characters, with dashes
between the words used.
This commit adds a light mention about that in the docs, encouraging the
practice.
Author: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Discussion: https://postgr.es/m/OSCPR01MB14966E14C1378DEE51FB7B7C5F5B32@OSCPR01MB14966.jpnprd01.prod.outlook.com
Backpatch-through: 17
* Use <symbol> tags for CONNECTION_* #defines
We were using an inconsistent mix of <literal> and sometimes <function>
tags.
* Use <application> tag for libpq
There was a mix of <literal> and <productname>
Also fix a whitespace issue.
None of these seem critical enough mistakes to backpatch.
Author: Noboru Saito <noborusai@gmail.com>
Discussion: https://postgr.es/m/CAAM3qnJtv5YbjpwDfVOYN2gZ9zGSLFM1UGJgptSXmwfifOZJFQ@mail.gmail.com
Commit d9e03864b6b changed the memory context level numbers shown by
pg_log_backend_memory_contexts() to be 1-based. However, the example in
the documentation was not updated and still used 0-based numbering.
This commit updates the example to match the current 1-based output.
Author: Fujii Masao <masao.fujii@gmail.com>
Reviewed-by: David Rowley <drowleyml@gmail.com>
Discussion: https://postgr.es/m/1ad6d388-1b43-400d-bec9-36d52f755f74@oss.nttdata.com
Backpatch to 17, where the line was added.
Reported by Noboru Saito while he was working on translating the file
into Japanese.
Discussion: https://postgr.es/m/20250417.203047.1321297410457834775.ishii%40postgresql.org
Reported-by: Noboru Saito <noborusai@gmail.com>
Reviewed-by: Daniel Gustafs <daniel@yesql.se>
Backpatch-through: 17
Previously, a space was missing between "<option>--exclude-schema</option>"
and "for" in the pg_restore documentation. This commit fixes the typo by
adding the missing whitespace.
Back-patch to v17 where the typo was added.
Author: Lele Gaifax <lele@metapensiero.it>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/87lds3ysm0.fsf@metapensiero.it
Backpatch-through: 17
Per the precedent set by 04539e73f, adjust article prefixes for "SQL" to
use "an" consistently rather than "a", i.e., "an es-que-ell" rather than
"a sequel".
Both of these are new to v18. Also see b1b13d2b5, d866f0374 and
7bdd489d3.
Add a paragraph break per suggestion from David G. Johnston.
Use a consistent voice for all the different parameter
descriptions, and fix a couple of grammatical issues.
Reported-by: Igor Korot <ikorot01@gmail.com>
Co-authored-by: "David G. Johnston" <david.g.johnston@gmail.com>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA+FnnTz=EW1VQRpWB9J+G-NSchrPFcw4nR7d0JqzEK9jWKB35A@mail.gmail.com
It's been twenty years since we generated constraint names that
look like "$N". So this advice about double-quoting such names
is well past its sell-by date, and now it merely seems confusing.
Reported-by: Yaroslav Saburov <y.saburov@gmail.com>
Author: "David G. Johnston" <david.g.johnston@gmail.com>
Discussion: https://postgr.es/m/174393459040.678.17810152410419444783@wrigleys.postgresql.org
Backpatch-through: 13
It's weird to have the core regression tests depending on contrib
code, and coverage testing shows that those test queries add nothing
to the core-code coverage of the core tests. So pull those test bits
out and put them into ordinary test scripts inside contrib/spi/,
making that more like other contrib modules.
Aside from being structurally nicer, anything we can take out of the
core tests (which are executed multiple times per check-world run)
and put into tests executed only once should be a win. It doesn't
look like this change will buy a whole lot of milliseconds, but a
cycle saved is a cycle earned.
Also, there is some discussion around possibly removing refint and/or
autoinc altogether. I don't know if that will happen, but we'd
certainly need to decouple them from the core tests to do so.
The tests for autoinc were quite intertwined with the undocumented
"ttdummy" trigger in regress.c. That made the tests very hard to
understand and contributed nothing to autoinc's testing either.
So I just deleted ttdummy and rewrote the autoinc tests without it.
I realized while doing this that the description of autoinc in
the SGML docs is not a great description of what the function
actually does, so the patch includes some updates to those docs.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/3872677.1744077559@sss.pgh.pa.us
The page_num was defined as integer, which should be sufficient for the
near future (with 4K pages it's 8TB). But it's virtually free to return
bigint, and get a wider range. This was agreed on the thread, but I
forgot to tweak this in ba2a3c2302f1.
While at it, make the data types in CREATE VIEW a bit more consistent.
Discussion: https://postgr.es/m/CAKZiRmxh6KWo0aqRqvmcoaX2jUxZYb4kGp3N%3Dq1w%2BDiH-696Xw%40mail.gmail.co
It can be set to either COPY (the default) or CLONE if the system
supports it. CLONE causes callers of copydir(), currently CREATE
DATABASE ... STRATEGY=FILE_COPY and ALTER DATABASE ... SET TABLESPACE =
..., to use copy_file_range (Linux, FreeBSD) or copyfile (macOS) to copy
files instead of a read-write loop over the contents.
CLONE gives the kernel the opportunity to share block ranges on
copy-on-write file systems and push copying down to storage on others,
depending on configuration. On some systems CLONE can be used to clone
large databases quickly with CREATE DATABASE ... TEMPLATE=source
STRATEGY=FILE_COPY.
Other operating systems could be supported; patches welcome.
Co-authored-by: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Ranier Vilela <ranier.vf@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGLM%2Bt%2BSwBU-cHeMUXJCOgBxSHLGZutV5zCwY4qrCcE02w%40mail.gmail.com
This adds a function for retrieving memory context statistics
and information from backends as well as auxiliary processes.
The intended usecase is cluster debugging when under memory
pressure or unanticipated memory usage characteristics.
When calling the function it sends a signal to the specified
process to submit statistics regarding its memory contexts
into dynamic shared memory. Each memory context is returned
in detail, followed by a cumulative total in case the number
of contexts exceed the max allocated amount of shared memory.
Each process is limited to use at most 1Mb memory for this.
A summary can also be explicitly requested by the user, this
will return the TopMemoryContext and a cumulative total of
all lower contexts.
In order to not block on busy processes the caller specifies
the number of seconds during which to retry before timing out.
In the case where no statistics are published within the set
timeout, the last known statistics are returned, or NULL if
no previously published statistics exist. This allows dash-
board type queries to continually publish even if the target
process is temporarily congested. Context records contain a
timestamp to indicate when they were submitted.
Author: Rahila Syed <rahilasyed90@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Reviewed-by: Atsushi Torikoshi <torikoshia@oss.nttdata.com>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Discussion: https://postgr.es/m/CAH2L28v8mc9HDt8QoSJ8TRmKau_8FM_HKS41NeO9-6ZAkuZKXw@mail.gmail.com
In addition to the added functions, the pg_buffercache_evict() function now
shows whether the buffer was flushed.
pg_buffercache_evict_relation(): Evicts all shared buffers in a
relation at once.
pg_buffercache_evict_all(): Evicts all shared buffers at once.
Both functions provide mechanism to evict multiple shared buffers at
once. They are designed to address the inefficiency of repeatedly calling
pg_buffercache_evict() for each individual buffer, which can be time-consuming
when dealing with large shared buffer pools. (e.g., ~477ms vs. ~2576ms for
16GB of fully populated shared buffers).
These functions are intended for developer testing and debugging
purposes and are available to superusers only.
Minimal tests for the new functions are included. Also, there was no test for
pg_buffercache_evict(), test for this added too.
No new extension version is needed, as it was already increased this release
by ba2a3c2302f.
Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Aidar Imamov <a.imamov@postgrespro.ru>
Reviewed-by: Joseph Koshakow <koshy44@gmail.com>
Discussion: https://postgr.es/m/CAN55FZ0h_YoSqqutxV6DES1RW8ig6wcA8CR9rJk358YRMxZFmw%40mail.gmail.com
A PG 17 optimization allowed columns with NOT NULL constraints to skip
table scans for IS NULL queries, and to skip IS NOT NULL checks for IS
NOT NULL queries. This didn't work for domain types, since domain types
don't follow the IS NULL/IS NOT NULL constraint logic. To fix, disable
this optimization for domains for PG 17+.
Reported-by: Jan Behrens
Diagnosed-by: Tom Lane
Discussion: https://postgr.es/m/Z37p0paENWWUarj-@momjian.us
Backpatch-through: 17
Introduces a new view pg_buffercache_numa, showing NUMA memory nodes
for individual buffers. For each buffer the view returns an entry for
each memory page, with the associated NUMA node.
The database blocks and OS memory pages may have different size - the
default block size is 8KB, while the memory page is 4K (on x86). But
other combinations are possible, depending on configure parameters,
platform, etc. This means buffers may overlap with multiple memory
pages, each associated with a different NUMA node.
To determine the NUMA node for a buffer, we first need to touch the
memory pages using pg_numa_touch_mem_if_required, otherwise we might get
status -2 (ENOENT = The page is not present), indicating the page is
either unmapped or unallocated.
The view may be relatively expensive, especially when accessed for the
first time in a backend, as it touches all memory pages to get reliable
information about the NUMA node. This may also force allocation of the
shared memory.
Author: Jakub Wartak <jakub.wartak@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Discussion: https://postgr.es/m/CAKZiRmxh6KWo0aqRqvmcoaX2jUxZYb4kGp3N%3Dq1w%2BDiH-696Xw%40mail.gmail.com
Introduce new pg_shmem_alloctions_numa view with information about how
shared memory is distributed across NUMA nodes. For each shared memory
segment, the view returns one row for each NUMA node backing it, with
the total amount of memory allocated from that node.
The view may be relatively expensive, especially when executed for the
first time in a backend, as it has to touch all memory pages to get
reliable information about the NUMA node. This may also force allocation
of the shared memory.
Unlike pg_shmem_allocations, the view does not show anonymous shared
memory allocations. It also does not show memory allocated using the
dynamic shared memory infrastructure.
Author: Jakub Wartak <jakub.wartak@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Discussion: https://postgr.es/m/CAKZiRmxh6KWo0aqRqvmcoaX2jUxZYb4kGp3N%3Dq1w%2BDiH-696Xw%40mail.gmail.com
Add basic NUMA awareness routines, using a minimal src/port/pg_numa.c
portability wrapper and an optional build dependency, enabled by
--with-libnuma configure option. For now this is Linux-only, other
platforms may be supported later.
A built-in SQL function pg_numa_available() allows checking NUMA
support, i.e. that the server was built/linked with the NUMA library.
The main function introduced is pg_numa_query_pages(), which allows
determining the NUMA node for individual memory pages. Internally the
function uses move_pages(2) syscall, as it allows batching, and is more
efficient than get_mempolicy(2).
Author: Jakub Wartak <jakub.wartak@enterprisedb.com>
Co-authored-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Discussion: https://postgr.es/m/CAKZiRmxh6KWo0aqRqvmcoaX2jUxZYb4kGp3N%3Dq1w%2BDiH-696Xw%40mail.gmail.com
check_foreign_key incorrectly used a single cache entry for its saved
plans for a 'c' (cascade) trigger, although there are two different
queries to execute depending on whether it fires for an update or a
delete. This caused the wrong things to be done if both types of
event occur in one session. (This was indeed visible in the triggers
regression test, but apparently nobody ever questioned it.) To fix,
add the operation type to the cache key.
Its debug log output failed to distinguish update from delete
events, too.
Also, change the intended trigger usage from BEFORE ROW to AFTER ROW,
and add checks insisting on that usage. BEFORE is really rather
unsafe, since if there are other BEFORE triggers they might change or
cancel the operation we are trying to check. AFTER triggers are the
standard way to propagate changes to other rows, so we should follow
that way here.
In passing, remove a useless duplicate lookup of the cache entry.
This code is mostly intended as a documentation example, so we
won't consider a back-patch.
Author: Dmitrii Bondar <d.bondar@postgrespro.ru>
Reviewed-by: Paul Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Lilian Ontowhee <ontowhee@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/79755a2b18ed4fe5e29da6a87a1e00d1@postgrespro.ru
This allows them to be added without scanning the table, and validating
them afterwards without holding access exclusive lock on the table after
any violating rows have been deleted or fixed.
Doing ALTER TABLE ... SET NOT NULL for a column that has an invalid
not-null constraint validates that constraint. ALTER TABLE .. VALIDATE
CONSTRAINT is also supported. There are various checks on whether an
invalid constraint is allowed in a child table when the parent table has
a valid constraint; this should match what we do for enforced/not
enforced constraints.
pg_attribute.attnotnull is now only an indicator for whether a not-null
constraint exists for the column; whether it's valid or invalid must be
queried in pg_constraint. Applications can continue to query
pg_attribute.attnotnull as before, but now it's possible that NULL rows
are present in the column even when that's set to true.
For backend internal purposes, we cache the nullability status in
CompactAttribute->attnullability that each tuple descriptor carries
(replacing CompactAttribute.attnotnull, which was a mirror of
Form_pg_attribute.attnotnull). During the initial tuple descriptor
creation, based on the pg_attribute scan, we set this to UNRESTRICTED if
pg_attribute.attnotnull is false, or to UNKNOWN if it's true; then we
update the latter to VALID or INVALID depending on the pg_constraint
scan. This flag is also copied when tupledescs are copied.
Comparing tuple descs for equality must also compare the
CompactAttribute.attnullability flag and return false in case of a
mismatch.
pg_dump deals with these constraints by storing the OIDs of invalid
not-null constraints in a separate array, and running a query to obtain
their properties. The regular table creation SQL omits them entirely.
They are then dealt with in the same way as "separate" CHECK
constraints, and dumped after the data has been loaded. Because no
additional pg_dump infrastructure was required, we don't bump its
version number.
I decided not to bump catversion either, because the old catalog state
works perfectly in the new world. (Trying to run with new catalog state
and the old server version would likely run into issues, however.)
System catalogs do not support invalid not-null constraints (because
commit 14e87ffa5c54 didn't allow them to have pg_constraint rows
anyway.)
Author: Rushabh Lathia <rushabh.lathia@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Tested-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Discussion: https://postgr.es/m/CAGPqQf0KitkNack4F5CFkFi-9Dqvp29Ro=EpcWt=4_hs-Rt+bQ@mail.gmail.com
