Commit Graph

10882 Commits

Author SHA1 Message Date
Jeff Davis ea1db8ae70 Canonicalize ICU locale names to language tags.
Convert to BCP47 language tags before storing in the catalog, except
during binary upgrade or when the locale comes from an existing
collation or template database.

The resulting language tags can vary slightly between ICU
versions. For instance, "@colBackwards=yes" is converted to
"und-u-kb-true" in older versions of ICU, and to the simpler (but
equivalent) "und-u-kb" in newer versions.

The process of canonicalizing to a language tag also understands more
input locale string formats than ucol_open(). For instance,
"fr_CA.UTF-8" is misinterpreted by ucol_open() and the region is
ignored; effectively treating it the same as the locale "fr" and
opening the wrong collator. Canonicalization properly interprets the
language and region, resulting in the language tag "fr-CA", which can
then be understood by ucol_open().

This commit fixes a problem in prior versions due to ucol_open()
misinterpreting locale strings as described above. For instance,
creating an ICU collation with locale "fr_CA.UTF-8" would store that
string directly in the catalog, which would later be passed to (and
misinterpreted by) ucol_open(). After this commit, the locale string
will be canonicalized to language tag "fr-CA" in the catalog, which
will be properly understood by ucol_open(). Because this fix affects
the resulting collator, we cannot change the locale string stored in
the catalog for existing databases or collations; otherwise we'd risk
corrupting indexes. Therefore, only canonicalize locales for
newly-created (not upgraded) collations/databases. For similar
reasons, do not backport.

Discussion: https://postgr.es/m/8c7af6820aed94dc7bc259d2aa7f9663518e6137.camel@j-davis.com
Reviewed-by: Peter Eisentraut
2023-04-04 10:38:58 -07:00
Robert Haas 482675987b Add a run_as_owner option to subscriptions.
This option is normally false, but can be set to true to obtain
the legacy behavior where the subscription runs with the permissions
of the subscription owner rather than the permissions of the
table owner. The advantages of this mode are (1) it doesn't require
that the subscription owner have permission to SET ROLE to each
table owner and (2) since no role switching occurs, the
SECURITY_RESTRICTED_OPERATION restrictions do not apply.

On the downside, it allows any table owner to easily usurp
the privileges of the subscription owner - basically, to take
over their account. Because that's generally quite undesirable,
we don't make this mode the default, but we do make it available,
just in case the new behavior causes too many problems for someone.

Discussion: http://postgr.es/m/CA+TgmoZ-WEeG6Z14AfH7KhmpX2eFh+tZ0z+vf0=eMDdbda269g@mail.gmail.com
2023-04-04 12:03:03 -04:00
Robert Haas 1e10d49b65 Perform logical replication actions as the table owner.
Up until now, logical replication actions have been performed as the
subscription owner, who will generally be a superuser.  Commit
cec57b1a0f documented hazards
associated with that situation, namely, that any user who owns a
table on the subscriber side could assume the privileges of the
subscription owner by attaching a trigger, expression index, or
some other kind of executable code to it. As a remedy, it suggested
not creating configurations where users who are not fully trusted
own tables on the subscriber.

Although that will work, it basically precludes using logical
replication in the way that people typically want to use it,
namely, to replicate a database from one node to another
without necessarily having any restrictions on which database
users can own tables. So, instead, change logical replication to
execute INSERT, UPDATE, DELETE, and TRUNCATE operations as the
table owner when they are replicated.

Since this involves switching the active user frequently within
a session that is authenticated as the subscription user, also
impose SECURITY_RESTRICTED_OPERATION restrictions on logical
replication code. As an exception, if the table owner can SET
ROLE to the subscription owner, these restrictions have no
security value, so don't impose them in that case.

Subscription owners are now required to have the ability to
SET ROLE to every role that owns a table that the subscription
is replicating. If they don't, replication will fail. Superusers,
who normally own subscriptions, satisfy this property by default.
Non-superusers users who own subscriptions will need to be
granted the roles that own relevant tables.

Patch by me, reviewed (but not necessarily in its entirety) by
Jelte Fennema, Jeff Davis, and Noah Misch.

Discussion: http://postgr.es/m/CA+TgmoaSCkg9ww9oppPqqs+9RVqCexYCE6Aq=UsYPfnOoDeFkw@mail.gmail.com
2023-04-04 11:25:23 -04:00
Alvaro Herrera 71bfd1543f
Code review for recent SQL/JSON commits
- At the last minute and for no particularly good reason, I changed the
  WITHOUT token to be marked especially for lookahead, from the one in
  WITHOUT TIME to the one in WITHOUT UNIQUE.  Study of upcoming patches
  (where a new WITHOUT ARRAY WRAPPER clause is added) showed me that the
  former was better, so put it back the way the original patch had it.

- update exprTypmod() for JsonConstructorExpr to return the typmod of
  the RETURNING clause, as a comment there suggested.  Perhaps it's
  possible for this to make a difference with datetime types, but I
  didn't try to build a test case.

- The nodeFuncs.c support code for new nodes was calling walker()
  directly instead of the WALK() macro as introduced by commit 1c27d16e6e.
  Modernize that.  Also add exprLocation() support for a couple of nodes
  that missed it.  Lastly, reorder the code more sensibly.

The WITHOUT_LA -> WITHOUT change means that stored rules containing
either WITHOUT TIME ZONE or WITHOUT UNIQUE KEYS would change
representation.  Therefore, bump catversion.

Discussion: https://postgr.es/m/20230329181708.e64g2tpy7jyufqkr@alvherre.pgsql
2023-04-04 14:04:30 +02:00
Peter Geoghegan e48c817395 Recycle deleted nbtree pages more aggressively.
Commit 61b313e4 made nbtree consistently pass down a heaprel to low
level routines like _bt_getbuf().  Although this was primarily intended
as preparation for logical decoding on standbys, it also made it easy to
correct an old deficiency in how nbtree VACUUM determines whether or not
it's now safe to recycle deleted pages.

Pass the heaprel to GlobalVisTestFor() in nbtree routines that deal with
recycle safety.  nbtree now makes less pessimistic assumptions about
recycle safety within non-catalog relations.  This enhancement
complements the recycling enhancement added by commit 9dd963ae25.

nbtree remains just as pessimistic as ever when it comes to recycle
safety within indexes on catalog relations.  There is no fundamental
reason why we need to treat catalog relations differently, though.  The
behavioral inconsistency is a consequence of the way that nbtree uses
nextXID values to implement what Lanin and Shasha call "the drain
technique".  Note in particular that it has nothing to do with whether
or not index tuples might still be required for an older MVCC snapshot.

Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/CAH2-WzkaiDxCje0yPuH=3Uh2p1V_2pFGY==xfbZoZu7Ax_NB8g@mail.gmail.com
2023-04-03 11:31:43 -07:00
Peter Geoghegan a349b86603 Move heaprel struct field next to index rel field.
Commit 61b313e4 added a heaprel struct member to IndexVacuumInfo, but
placed it last.  Move the heaprel struct member next to the index struct
member to improve the code's readability.

Author: Peter Geoghegan <pg@bowt.ie>
Discussion: https://postgr.es/m/CAH2-WznG=TV6S9d3VA=y0vBHbXwnLs9_LLdiML=aNJuHeriwxg@mail.gmail.com
2023-04-03 11:01:11 -07:00
Alexander Korotkov 2b65bf046d Revert 11470f544e
Discussion: https://postgr.es/m/20230323003003.plgaxjqahjgkuxrk%40awork3.anarazel.de
2023-04-03 16:54:31 +03:00
Andres Freund 6af1793954 Add info in WAL records in preparation for logical slot conflict handling
This commit only implements one prerequisite part for allowing logical
decoding. The commit message contains an explanation of the overall design,
which later commits will refer back to.

Overall design:

1. We want to enable logical decoding on standbys, but replay of WAL
from the primary might remove data that is needed by logical decoding,
causing error(s) on the standby. To prevent those errors, a new replication
conflict scenario needs to be addressed (as much as hot standby does).

2. Our chosen strategy for dealing with this type of replication slot
is to invalidate logical slots for which needed data has been removed.

3. To do this we need the latestRemovedXid for each change, just as we
do for physical replication conflicts, but we also need to know
whether any particular change was to data that logical replication
might access. That way, during WAL replay, we know when there is a risk of
conflict and, if so, if there is a conflict.

4. We can't rely on the standby's relcache entries for this purpose in
any way, because the startup process can't access catalog contents.

5. Therefore every WAL record that potentially removes data from the
index or heap must carry a flag indicating whether or not it is one
that might be accessed during logical decoding.

Why do we need this for logical decoding on standby?

First, let's forget about logical decoding on standby and recall that
on a primary database, any catalog rows that may be needed by a logical
decoding replication slot are not removed.

This is done thanks to the catalog_xmin associated with the logical
replication slot.

But, with logical decoding on standby, in the following cases:

- hot_standby_feedback is off
- hot_standby_feedback is on but there is no a physical slot between
  the primary and the standby. Then, hot_standby_feedback will work,
  but only while the connection is alive (for example a node restart
  would break it)

Then, the primary may delete system catalog rows that could be needed
by the logical decoding on the standby (as it does not know about the
catalog_xmin on the standby).

So, it’s mandatory to identify those rows and invalidate the slots
that may need them if any. Identifying those rows is the purpose of
this commit.

Implementation:

When a WAL replay on standby indicates that a catalog table tuple is
to be deleted by an xid that is greater than a logical slot's
catalog_xmin, then that means the slot's catalog_xmin conflicts with
the xid, and we need to handle the conflict. While subsequent commits
will do the actual conflict handling, this commit adds a new field
isCatalogRel in such WAL records (and a new bit set in the
xl_heap_visible flags field), that is true for catalog tables, so as to
arrange for conflict handling.

The affected WAL records are the ones that already contain the
snapshotConflictHorizon field, namely:

- gistxlogDelete
- gistxlogPageReuse
- xl_hash_vacuum_one_page
- xl_heap_prune
- xl_heap_freeze_page
- xl_heap_visible
- xl_btree_reuse_page
- xl_btree_delete
- spgxlogVacuumRedirect

Due to this new field being added, xl_hash_vacuum_one_page and
gistxlogDelete do now contain the offsets to be deleted as a
FLEXIBLE_ARRAY_MEMBER. This is needed to ensure correct alignment.
It's not needed on the others struct where isCatalogRel has
been added.

This commit just introduces the WAL format changes mentioned above. Handling
the actual conflicts will follow in future commits.

Bumps XLOG_PAGE_MAGIC as the several WAL records are changed.

Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Author: Andres Freund <andres@anarazel.de> (in an older version)
Author: Amit Khandekar <amitdkhan.pg@gmail.com>  (in an older version)
Reviewed-by: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
2023-04-02 12:32:19 -07:00
Andres Freund 61b313e47e Pass down table relation into more index relation functions
This is done in preparation for logical decoding on standby, which needs to
include whether visibility affecting WAL records are about a (user) catalog
table. Which is only known for the table, not the indexes.

It's also nice to be able to pass the heap relation to GlobalVisTestFor() in
vacuumRedirectAndPlaceholder().

Author: "Drouvot, Bertrand" <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/21b700c3-eecf-2e05-a699-f8c78dd31ec7@gmail.com
2023-04-01 20:18:29 -07:00
Alvaro Herrera 6ee30209a6
SQL/JSON: support the IS JSON predicate
This patch introduces the SQL standard IS JSON predicate. It operates
on text and bytea values representing JSON, as well as on the json and
jsonb types. Each test has IS and IS NOT variants and supports a WITH
UNIQUE KEYS flag. The tests are:

IS JSON [VALUE]
IS JSON ARRAY
IS JSON OBJECT
IS JSON SCALAR

These should be self-explanatory.

The WITH UNIQUE KEYS flag makes these return false when duplicate keys
exist in any object within the value, not necessarily directly contained
in the outermost object.

Author: Nikita Glukhov <n.gluhov@postgrespro.ru>
Author: Teodor Sigaev <teodor@sigaev.ru>
Author: Oleg Bartunov <obartunov@gmail.com>
Author: Alexander Korotkov <aekorotkov@gmail.com>
Author: Amit Langote <amitlangote09@gmail.com>
Author: Andrew Dunstan <andrew@dunslane.net>

Reviewers have included (in no particular order) Andres Freund, Alexander
Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu,
Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby.

Discussion: https://postgr.es/m/CAF4Au4w2x-5LTnN_bxky-mq4=WOqsGsxSpENCzHRAzSnEd8+WQ@mail.gmail.com
Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Discussion: https://postgr.es/m/20220616233130.rparivafipt6doj3@alap3.anarazel.de
Discussion: https://postgr.es/m/abd9b83b-aa66-f230-3d6d-734817f0995d%40postgresql.org
2023-03-31 22:34:04 +02:00
Alvaro Herrera 9b058f6b0d
Move ExecEvalJsonConstructor new function to a more natural place
Commit 7081ac46ac put it at the end of the file, but that doesn't look
very nice.
2023-03-31 12:55:25 +02:00
Andres Freund f95c1cd6b2 Bump PGSTAT_FILE_FORMAT_ID, omitted in 8aaa04b32d
I forgot to do so in the referenced commit. While the consequences of omitting
the version change are likely to be harmless (besides discarding stats, as a
PGSTAT_FILE_FORMAT_ID bump also does), it still seems worth doing.
2023-03-30 19:48:01 -07:00
Andres Freund 8aaa04b32d Track shared buffer hits in pg_stat_io
Among other things, this should make it easier to calculate a useful cache hit
ratio by excluding buffer reads via buffer access strategies. As buffer access
strategies reuse buffers (and thus evict the prior buffer contents), it is
normal to see reads on repeated scans of the same data.

Author: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CAAKRu_beMa9Hzih40%3DXPYqhDVz6tsgUGTrhZXRo%3Dunp%2Bszb%3DUA%40mail.gmail.com
2023-03-30 19:24:21 -07:00
Thomas Munro 11c2d6fdf5 Parallel Hash Full Join.
Full and right outer joins were not supported in the initial
implementation of Parallel Hash Join because of deadlock hazards (see
discussion).  Therefore FULL JOIN inhibited parallelism, as the other
join strategies can't do that in parallel either.

Add a new PHJ phase PHJ_BATCH_SCAN that scans for unmatched tuples on
the inner side of one batch's hash table.  For now, sidestep the
deadlock problem by terminating parallelism there.  The last process to
arrive at that phase emits the unmatched tuples, while others detach and
are free to go and work on other batches, if there are any, but
otherwise they finish the join early.

That unfairness is considered acceptable for now, because it's better
than no parallelism at all.  The build and probe phases are run in
parallel, and the new scan-for-unmatched phase, while serial, is usually
applied to the smaller of the two relations and is either limited by
some multiple of work_mem, or it's too big and is partitioned into
batches and then the situation is improved by batch-level parallelism.

Author: Melanie Plageman <melanieplageman@gmail.com>
Author: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKG%2BA6ftXPz4oe92%2Bx8Er%2BxpGZqto70-Q_ERwRaSyA%3DafNg%40mail.gmail.com
2023-03-31 11:34:03 +13:00
Andres Freund ca7b3c4c00 pg_stat_wal: Accumulate time as instr_time instead of microseconds
In instr_time.h it is stated that:

* When summing multiple measurements, it's recommended to leave the
* running sum in instr_time form (ie, use INSTR_TIME_ADD or
* INSTR_TIME_ACCUM_DIFF) and convert to a result format only at the end.

The reason for that is that converting to microseconds is not cheap, and can
loose precision.  Therefore this commit changes 'PendingWalStats' to use
'instr_time' instead of 'PgStat_Counter' while accumulating 'wal_write_time'
and 'wal_sync_time'.

Author: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://postgr.es/m/1feedb83-7aa9-cb4b-5086-598349d3f555@gmail.com
2023-03-30 14:23:14 -07:00
Alvaro Herrera 60966f56c3
Fix inconsistencies and style issues in new SQL/JSON code
Reported by Alexander Lakhin.

Discussion: https://postgr.es/m/60483139-5c34-851d-baee-6c0d014e1710@gmail.com
2023-03-30 21:06:31 +02:00
Robert Haas c3afe8cf5a Add new predefined role pg_create_subscription.
This role can be granted to non-superusers to allow them to issue
CREATE SUBSCRIPTION. The non-superuser must additionally have CREATE
permissions on the database in which the subscription is to be
created.

Most forms of ALTER SUBSCRIPTION, including ALTER SUBSCRIPTION .. SKIP,
now require only that the role performing the operation own the
subscription, or inherit the privileges of the owner. However, to
use ALTER SUBSCRIPTION ... RENAME or ALTER SUBSCRIPTION ... OWNER TO,
you also need CREATE permission on the database. This is similar to
what we do for schemas. To change the owner of a schema, you must also
have permission to SET ROLE to the new owner, similar to what we do
for other object types.

Non-superusers are required to specify a password for authentication
and the remote side must use the password, similar to what is required
for postgres_fdw and dblink.  A superuser who wants a non-superuser to
own a subscription that does not rely on password authentication may
set the new password_required=false property on that subscription. A
non-superuser may not set password_required=false and may not modify a
subscription that already has password_required=false.

This new password_required subscription property works much like the
eponymous postgres_fdw property.  In both cases, the actual semantics
are that a password is not required if either (1) the property is set
to false or (2) the relevant user is the superuser.

Patch by me, reviewed by Andres Freund, Jeff Davis, Mark Dilger,
and Stephen Frost (but some of those people did not fully endorse
all of the decisions that the patch makes).

Discussion: http://postgr.es/m/CA+TgmoaDH=0Xj7OBiQnsHTKcF2c4L+=gzPBUKSJLh8zed2_+Dg@mail.gmail.com
2023-03-30 11:37:19 -04:00
David Rowley 902ecd3bd4 Fix outdated comments regarding TupleTableSlots
The tts_flag is named TTS_FLAG_SHOULDFREE, so use that instead of
TTS_SHOULDFREE, which is the name of the macro that checks for that flag.

Additionally, 4da597edf got rid of the TupleTableSlot.tts_tuple field but
forgot to update a comment which referenced that field.  Fix that.

Reported-by: Zhen Mingyang <zhenmingyang@yeah.net>
Reported-by: Richard Guo <guofenglinux@gmail.com>
Discussion: https://postgr.es/m/1a96696c.9d3.187193989c3.Coremail.zhenmingyang@yeah.net
2023-03-30 16:37:03 +13:00
Daniel Gustafsson 44d85ba5a3 Copy and store addrinfo in libpq-owned private memory
This refactors libpq to copy addrinfos returned by getaddrinfo to
memory owned by libpq such that future improvements can alter for
example the order of entries.

As a nice side effect of this refactor the mechanism for iteration
over addresses in PQconnectPoll is now identical to its iteration
over hosts.

Author: Jelte Fennema <postgres@jeltef.nl>
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Reviewed-by: Michael Banck <mbanck@gmx.net>
Reviewed-by: Andrey Borodin <amborodin86@gmail.com>
Discussion: https://postgr.es/m/PR3PR83MB04768E2FF04818EEB2179949F7A69@PR3PR83MB0476.EURPRD83.prod.outlook.com
2023-03-29 21:41:27 +02:00
Tom Lane 58c9600a9f Remove empty function BufmgrCommit().
This function has been a no-op for over a decade.  Even if bufmgr
regains a need to be called during commit, it seems unlikely that
the most appropriate call points would be precisely here, so it's not
doing us much good as a placeholder either.  Now, removing it probably
doesn't save any noticeable number of cycles --- but the main call is
inside the commit critical section, and the less work done there the
better.

Matthias van de Meent

Discussion: https://postgr.es/m/CAEze2Wi1=tLKbxZnXzcD+8fYKyKqBtivVakLQC_mYBsP4Y8qVA@mail.gmail.com
2023-03-29 09:13:57 -04:00
Alvaro Herrera 7081ac46ac
SQL/JSON: add standard JSON constructor functions
This commit introduces the SQL/JSON standard-conforming constructors for
JSON types:

JSON_ARRAY()
JSON_ARRAYAGG()
JSON_OBJECT()
JSON_OBJECTAGG()

Most of the functionality was already present in PostgreSQL-specific
functions, but these include some new functionality such as the ability
to skip or include NULL values, and to allow duplicate keys or throw
error when they are found, as well as the standard specified syntax to
specify output type and format.

Author: Nikita Glukhov <n.gluhov@postgrespro.ru>
Author: Teodor Sigaev <teodor@sigaev.ru>
Author: Oleg Bartunov <obartunov@gmail.com>
Author: Alexander Korotkov <aekorotkov@gmail.com>
Author: Amit Langote <amitlangote09@gmail.com>

Reviewers have included (in no particular order) Andres Freund, Alexander
Korotkov, Pavel Stehule, Andrew Alsup, Erik Rijkers, Zihong Yu,
Himanshu Upadhyaya, Daniel Gustafsson, Justin Pryzby.

Discussion: https://postgr.es/m/CAF4Au4w2x-5LTnN_bxky-mq4=WOqsGsxSpENCzHRAzSnEd8+WQ@mail.gmail.com
Discussion: https://postgr.es/m/cd0bb935-0158-78a7-08b5-904886deac4b@postgrespro.ru
Discussion: https://postgr.es/m/20220616233130.rparivafipt6doj3@alap3.anarazel.de
Discussion: https://postgr.es/m/abd9b83b-aa66-f230-3d6d-734817f0995d%40postgresql.org
2023-03-29 12:11:36 +02:00
Peter Eisentraut 563f21cda8 Move definition of standard collations from initdb to pg_collation.dat
The standard collations "ucs_basic" and "unicode" were defined in
initdb, even though pg_collation.dat seems like the correct place for
them.  It seems this was just forgotten during various reorganizations
of initdb and pg_collation.dat/.h over time.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/08b58ecd-0d50-9395-ed51-dc8294e3fd2b%40enterprisedb.com
2023-03-29 09:45:21 +02:00
Amit Kapila 062a844424 Avoid syncing data twice for the 'publish_via_partition_root' option.
When there are multiple publications for a subscription and one of those
publishes via the parent table by using publish_via_partition_root and the
other one directly publishes the child table, we end up copying the same
data twice during initial synchronization. The reason for this was that we
get both the parent and child tables from the publisher and try to copy
the data for both of them.

This patch extends the function pg_get_publication_tables() to take a
publication list as its input parameter. This allows us to exclude a
partition table whose ancestor is published by the same publication list.

This problem does exist in back-branches but we decide to fix it there in
a separate commit if required. The fix for back-branches requires quite
complicated changes to fetch the required table information from the
publisher as we can't update the function pg_get_publication_tables() in
back-branches. We are not sure whether we want to deviate and complicate
the code in back-branches for this problem as there are no field reports
yet.

Author: Wang wei
Reviewed-by: Peter Smith, Jacob Champion, Kuroda Hayato, Vignesh C, Osumi Takamichi, Amit Kapila
Discussion: https://postgr.es/m/OS0PR01MB57167F45D481F78CDC5986F794B99@OS0PR01MB5716.jpnprd01.prod.outlook.com
2023-03-29 10:46:58 +05:30
Jeff Davis 1671f990dd Validate ICU locales.
For ICU collations, ensure that the locale's language exists in ICU,
and that the locale can be opened.

Basic validation helps avoid minor mistakes and misspellings, which
often fall back to the root locale instead of the intended
locale. It's even more important to avoid such mistakes in ICU
versions 54 and earlier, where the same (misspelled) locale string
could fall back to different locales depending on the environment.

Discussion: https://postgr.es/m/11b1eeb7e7667fdd4178497aeb796c48d26e69b9.camel@j-davis.com
Discussion: https://postgr.es/m/df2efad0cae7c65180df8e5ebb709e5eb4f2a82b.camel@j-davis.com
Reviewed-by: Peter Eisentraut
2023-03-28 16:34:29 -07:00
Peter Eisentraut 90189eefc1 Save a few bytes in pg_attribute
Change the columns attndims, attstattarget, and attinhcount from int32
to int16, and reorder a bit.  This saves some space (currently 4
bytes) in pg_attribute and tuple descriptors, which translates into
small performance benefits and/or room for new columns in pg_attribute
needed by future features.

attndims and attinhcount are never realistically used with values
larger than int16.  Just to be sure, add some overflow checks.
attstattarget is currently limited explicitly to 10000.

For consistency, pg_constraint.coninhcount is also changed like
attinhcount.

Discussion: https://www.postgresql.org/message-id/flat/d07ffc2b-e0e8-77f7-38fb-be921dff71af%40enterprisedb.com
2023-03-28 10:05:56 +02:00
Daniel Gustafsson b577743000 Make SCRAM iteration count configurable
Replace the hardcoded value with a GUC such that the iteration
count can be raised in order to increase protection against
brute-force attacks.  The hardcoded value for SCRAM iteration
count was defined to be 4096, which is taken from RFC 7677, so
set the default for the GUC to 4096 to match.  In RFC 7677 the
recommendation is at least 15000 iterations but 4096 is listed
as a SHOULD requirement given that it's estimated to yield a
0.5s processing time on a mobile handset of the time of RFC
writing (late 2015).

Raising the iteration count of SCRAM will make stored passwords
more resilient to brute-force attacks at a higher computational
cost during connection establishment.  Lowering the count will
reduce computational overhead during connections at the tradeoff
of reducing strength against brute-force attacks.

There are however platforms where even a modest iteration count
yields a too high computational overhead, with weaker password
encryption schemes chosen as a result.  In these situations,
SCRAM with a very low iteration count still gives benefits over
weaker schemes like md5, so we allow the iteration count to be
set to one at the low end.

The new GUC is intentionally generically named such that it can
be made to support future SCRAM standards should they emerge.
At that point the value can be made into key:value pairs with
an undefined key as a default which will be backwards compatible
with this.

Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Jonathan S. Katz <jkatz@postgresql.org>
Discussion: https://postgr.es/m/F72E7BC7-189F-4B17-BF47-9735EB72C364@yesql.se
2023-03-27 09:46:29 +02:00
Daniel Gustafsson d435f15fff Add SysCacheGetAttrNotNull for guaranteed not-null attrs
When extracting an attr from a cached tuple in the syscache with
SysCacheGetAttr the isnull parameter must be checked in case the
attr cannot be NULL.  For cases when this is known beforehand, a
wrapper is introduced which perform the errorhandling internally
on behalf of the caller, invoking an elog in case of a NULL attr.

Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/AD76405E-DB45-46B6-941F-17B1EB3A9076@yesql.se
2023-03-25 22:49:33 +01:00
Tom Lane 27f5c712b2 Fix CREATE INDEX progress reporting for multi-level partitioning.
The "partitions_total" and "partitions_done" fields were updated
as though the current level of partitioning was the only one.
In multi-level cases, not only could partitions_total change
over the course of the command, but partitions_done could go
backwards or exceed the currently-reported partitions_total.

Fix by setting partitions_total to the total number of direct
and indirect children once at command start, and then just
incrementing partitions_done at appropriate points.  Invent
a new progress monitoring function "pgstat_progress_incr_param"
to simplify doing the latter.  We can avoid adding cost for the
former when doing CREATE INDEX, because ProcessUtility already
enumerates the children and it's pretty easy to pass the count
down to DefineIndex.  In principle the same could be done in
ALTER TABLE, but that's structurally difficult; for now, just
eat the cost of an extra find_all_inheritors scan in that case.

Ilya Gladyshev and Justin Pryzby

Discussion: https://postgr.es/m/a15f904a70924ffa4ca25c3c744cff31e0e6e143.camel@gmail.com
2023-03-25 15:34:03 -04:00
Tom Lane 3c05284d83 Invent GENERIC_PLAN option for EXPLAIN.
This provides a very simple way to see the generic plan for a
parameterized query.  Without this, it's necessary to define
a prepared statement and temporarily change plan_cache_mode,
which is a bit tedious.

One thing that's a bit of a hack perhaps is that we disable
execution-time partition pruning when the GENERIC_PLAN option
is given.  That's because the pruning code may attempt to
fetch the value of one of the parameters, which would fail.

Laurenz Albe, reviewed by Julien Rouhaud, Christoph Berg,
Michel Pelletier, Jim Jones, and myself

Discussion: https://postgr.es/m/0a29b954b10b57f0d135fe12aa0909bd41883eb0.camel@cybertec.at
2023-03-24 17:07:22 -04:00
Michael Paquier 36f40ce2dc libpq: Add sslcertmode option to control client certificates
The sslcertmode option controls whether the server is allowed and/or
required to request a certificate from the client.  There are three
modes:
- "allow" is the default and follows the current behavior, where a
configured client certificate is sent if the server requests one
(via one of its default locations or sslcert).  With the current
implementation, will happen whenever TLS is negotiated.
- "disable" causes the client to refuse to send a client certificate
even if sslcert is configured or if a client certificate is available in
one of its default locations.
- "require" causes the client to fail if a client certificate is never
sent and the server opens a connection anyway.  This doesn't add any
additional security, since there is no guarantee that the server is
validating the certificate correctly, but it may helpful to troubleshoot
more complicated TLS setups.

sslcertmode=require requires SSL_CTX_set_cert_cb(), available since
OpenSSL 1.0.2.  Note that LibreSSL does not include it.

Using a connection parameter different than require_auth has come up as
the simplest design because certificate authentication does not rely
directly on any of the AUTH_REQ_* codes, and one may want to require a
certificate to be sent in combination of a given authentication method,
like SCRAM-SHA-256.

TAP tests are added in src/test/ssl/, some of them relying on sslinfo to
check if a certificate has been set.  These are compatible across all
the versions of OpenSSL supported on HEAD (currently down to 1.0.1).

Author: Jacob Champion
Reviewed-by: Aleksander Alekseev, Peter Eisentraut, David G. Johnston,
Michael Paquier
Discussion: https://postgr.es/m/9e5a8ccddb8355ea9fa4b75a1e3a9edc88a70cd3.camel@vmware.com
2023-03-24 13:34:26 +09:00
Michael Paquier 8089517ab8 Rename fields in pgstat structures for functions and relations
This commit renames the members of a few pgstat structures related to
functions and relations, by respectively removing their prefix "f_" and
"t_".  The statistics for functions and relations and handled in their
own file, and pgstatfuncs.c associates each field in a structure
variable named based on the object type handled, so no information is
lost with this rename.

This will help with some of the refactoring aimed for pgstatfuncs.c, as
this makes more consistent the field names with the SQL functions
retrieving them.

Author: Bertrand Drouvot
Reviewed-by: Michael Paquier, Melanie Plageman
Discussion: https://postgr.es/m/9142f62a-a422-145c-bde0-b5bc498a4ada@gmail.com
2023-03-24 08:46:29 +09:00
Peter Geoghegan ae4fdde135 Count updates that move row to a new page.
Add pgstat counter to track row updates that result in the successor
version going to a new heap page, leaving behind an original version
whose t_ctid points to the new version.  The current count is shown by
the n_tup_newpage_upd column of each of the pg_stat_*_tables views.

The new n_tup_newpage_upd column complements the existing n_tup_hot_upd
and n_tup_upd columns.  Tables that have high n_tup_newpage_upd values
(relative to n_tup_upd) are good candidates for tuning heap fillfactor.

Corey Huinker, with small tweaks by me.

Author: Corey Huinker <corey.huinker@gmail.com>
Reviewed-By: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/CADkLM=ded21M9iZ36hHm-vj2rE2d=zcKpUQMds__Xm2pxLfHKA@mail.gmail.com
2023-03-23 11:16:17 -07:00
Thomas Munro 8fba928fd7 Improve the naming of Parallel Hash Join phases.
* Commit 3048898e dropped -ING from PHJ wait event names.  Update the
  corresponding barrier phases names to match.

* Rename the "DONE" phases to "FREE".  That's symmetrical with
  "ALLOCATE", and names the activity that actually happens in that phase
  (as we do for the other phases) rather than a state.  The bug fixed by
  commit 8d578b9b might have been more obvious with this name.

* Rename the batch/bucket growth barriers' "ALLOCATE" phases to
  "REALLOCATE", a better description of what they do.

* Update the high level comments about phases to highlight phases
  are executed by a single process with an asterisk (mostly memory
  management phases).

No behavior change, as this is just improving internal identifiers.  The
only user-visible sign of this is that a couple of wait events' display
names change from "...Allocate" to "...Reallocate" in pg_stat_activity,
to stay in sync with the internal names.

Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKG%2BMDpwF2Eo2LAvzd%3DpOh81wUTsrwU1uAwR-v6OGBB6%2B7g%40mail.gmail.com
2023-03-23 13:14:25 +13:00
Alexander Korotkov 11470f544e Allow locking updated tuples in tuple_update() and tuple_delete()
Currently, in read committed transaction isolation mode (default), we have the
following sequence of actions when tuple_update()/tuple_delete() finds
the tuple updated by concurrent transaction.

1. Attempt to update/delete tuple with tuple_update()/tuple_delete(), which
   returns TM_Updated.
2. Lock tuple with tuple_lock().
3. Re-evaluate plan qual (recheck if we still need to update/delete and
   calculate the new tuple for update).
4. Second attempt to update/delete tuple with tuple_update()/tuple_delete().
   This attempt should be successful, since the tuple was previously locked.

This patch eliminates step 2 by taking the lock during first
tuple_update()/tuple_delete() call.  Heap table access method saves some
efforts by checking the updated tuple once instead of twice.  Future
undo-based table access methods, which will start from the latest row version,
can immediately place a lock there.

The code in nodeModifyTable.c is simplified by removing the nested switch/case.

Discussion: https://postgr.es/m/CAPpHfdua-YFw3XTprfutzGp28xXLigFtzNbuFY8yPhqeq6X5kg%40mail.gmail.com
Reviewed-by: Aleksander Alekseev, Pavel Borisov, Vignesh C, Mason Sharp
Reviewed-by: Andres Freund, Chris Travers
2023-03-23 00:26:59 +03:00
Tom Lane b0d8f2d983 Add SHELL_ERROR and SHELL_EXIT_CODE magic variables to psql.
These are set after a \! command or a backtick substitution.
SHELL_ERROR is just "true" for error (nonzero exit status) or "false"
for success, while SHELL_EXIT_CODE records the actual exit status
following standard shell/system(3) conventions.

Corey Huinker, reviewed by Maxim Orlov and myself

Discussion: https://postgr.es/m/CADkLM=cWao2x2f+UDw15W1JkVFr_bsxfstw=NGea7r9m4j-7rQ@mail.gmail.com
2023-03-21 13:03:56 -04:00
Thomas Munro 8d578b9b2e Fix race in parallel hash join batch cleanup, take II.
With unlucky timing and parallel_leader_participation=off (not the
default), PHJ could attempt to access per-batch shared state just as it
was being freed.  There was code intended to prevent that by checking
for a cleared pointer, but it was racy.  Fix, by introducing an extra
barrier phase.  The new phase PHJ_BUILD_RUNNING means that it's safe to
access the per-batch state to find a batch to help with, and
PHJ_BUILD_DONE means that it is too late.  The last to detach will free
the array of per-batch state as before, but now it will also atomically
advance the phase, so that late attachers can avoid the hazard.  This
mirrors the way per-batch hash tables are freed (see phases
PHJ_BATCH_PROBING and PHJ_BATCH_DONE).

An earlier attempt to fix this (commit 3b8981b6, later reverted) missed
one special case.  When the inner side is empty (the "empty inner
optimization), the build barrier would only make it to
PHJ_BUILD_HASHING_INNER phase before workers attempted to detach from
the hashtable.  In that case, fast-forward the build barrier to
PHJ_BUILD_RUNNING before proceeding, so that our later assertions hold
and we can still negotiate who is cleaning up.

Revealed by build farm failures, where BarrierAttach() failed a sanity
check assertion, because the memory had been clobbered by dsa_free().
In non-assert builds, the result could be a segmentation fault.

Back-patch to all supported releases.

Author: Thomas Munro <thomas.munro@gmail.com>
Author: Melanie Plageman <melanieplageman@gmail.com>
Reported-by: Michael Paquier <michael@paquier.xyz>
Reported-by: David Geier <geidav.pg@gmail.com>
Tested-by: David Geier <geidav.pg@gmail.com>
Discussion: https://postgr.es/m/20200929061142.GA29096%40paquier.xyz
2023-03-21 14:29:34 +13:00
Tomas Vondra 19d8e2308b Ignore BRIN indexes when checking for HOT updates
When determining whether an index update may be skipped by using HOT, we
can ignore attributes indexed by block summarizing indexes without
references to individual tuples that need to be cleaned up.

A new type TU_UpdateIndexes provides a signal to the executor to
determine which indexes to update - no indexes, all indexes, or only the
summarizing indexes.

This also removes rd_indexattr list, and replaces it with rd_attrsvalid
flag. The list was not used anywhere, and a simple flag is sufficient.

This was originally committed as 5753d4ee32, but then got reverted by
e3fcca0d0d because of correctness issues.

Original patch by Josef Simanek, various fixes and improvements by Tomas
Vondra and me.

Authors: Matthias van de Meent, Josef Simanek, Tomas Vondra
Reviewed-by: Tomas Vondra, Alvaro Herrera
Discussion: https://postgr.es/m/05ebcb44-f383-86e3-4f31-0a97a55634cf@enterprisedb.com
Discussion: https://postgr.es/m/CAFp7QwpMRGcDAQumN7onN9HjrJ3u4X3ZRXdGFT0K5G2JWvnbWg%40mail.gmail.com
2023-03-20 11:02:42 +01:00
Tom Lane 75bd846b68 Add functions to do timestamptz arithmetic in a non-default timezone.
Add versions of timestamptz + interval, timestamptz - interval, and
generate_series(timestamptz, ...) in which a timezone can be specified
explicitly instead of defaulting to the TimeZone GUC setting.

The new functions for the first two are named date_add and
date_subtract.  This might seem too generic, but we could use
overloading to add additional variants if that seems useful.

Along the way, improve the docs' pretty inadequate explanation
of how timestamptz +- interval works.

Przemysław Sztoch and Gurjeet Singh; cosmetic changes and most of
the docs work by me

Discussion: https://postgr.es/m/01a84551-48dd-1359-bf7e-f6b0203a6bd0@sztoch.pl
2023-03-18 14:12:16 -04:00
Michael Paquier 0e681cf039 Add files related to query jumbling in src/include/nodes/ for meson
This caused ninja clean to not remove the two files generated by
gen_node_support.pl for the query jumbling, for example:
queryjumblefuncs.funcs.c and queryjumblefuncs.switch.c.

Reported-by: Pavel Stehule
Discussion: https://postgr.es/m/CAFj8pRBFiWVRyGYSPziyFuXJbHirNmfWwzbfTyCf8YOdiwK74w@mail.gmail.com
2023-03-18 18:04:04 +09:00
Tom Lane 3e59e5048d Refactor datetime functions' timezone lookup code to reduce duplication.
We already had five copies of essentially the same logic, and an
upcoming patch introduces yet another use-case.  That's past my
threshold of pain, so introduce a common subroutine.  There's not
that much net code savings, but the chance of typos should go down.

Inspired by a patch from Przemysław Sztoch, but different in detail.

Discussion: https://postgr.es/m/01a84551-48dd-1359-bf7e-f6b0203a6bd0@sztoch.pl
2023-03-17 17:47:19 -04:00
Jeff Davis f413941f41 Fix t_isspace(), etc., when datlocprovider=i and datctype=C.
Check whether the datctype is C to determine whether t_isspace() and
related functions use isspace() or iswspace().

Previously, t_isspace() checked whether the database default collation
was C; which is incorrect when the default collation uses the ICU
provider.

Discussion: https://postgr.es/m/79e4354d9eccfdb00483146a6b9f6295202e7890.camel@j-davis.com
Reviewed-by: Peter Eisentraut
Backpatch-through: 15
2023-03-17 12:08:46 -07:00
Amit Kapila e709596b25 Add macros for ReorderBufferTXN toptxn.
Currently, there are quite a few places in reorderbuffer.c that tries to
access top-transaction for a subtransaction. This makes the code to access
top-transaction consistent and easier to follow.

Author: Peter Smith
Reviewed-by: Vignesh C, Sawada Masahiko
Discussion: https://postgr.es/m/CAHut+PuCznOyTqBQwjRUu-ibG-=KHyCv-0FTcWQtZUdR88umfg@mail.gmail.com
2023-03-17 08:29:41 +05:30
Michael Paquier 98ae2c84a4 libpq: Remove code for SCM credential authentication
Support for SCM credential authentication has been removed in the
backend in 9.1, and libpq has kept some code to handle it for
compatibility.

Commit be4585b, that did the cleanup of the backend code, has done
so because the code was not really portable originally.  And, as there
are likely little chances that this is used these days, this removes the
remaining code from libpq.  An error will now be raised by libpq if
attempting to connect to a server that returns AUTH_REQ_SCM_CREDS,
instead.

References to SCM credential authentication are removed from the
protocol documentation.  This removes some meson and configure checks.

Author: Michael Paquier
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/ZBLH8a4otfqgd6Kn@paquier.xyz
2023-03-17 10:52:26 +09:00
Michael Paquier e731aeac89 Remove PgStat_BackendFunctionEntry
This structure included only PgStat_FunctionCounts, and removing it
facilitates some upcoming refactoring for pgstatfuncs.c to use more
macros rather that mostly-duplicated functions.

Author: Bertrand Drouvot
Reviewed-by: Nathan Bossart
Discussion: https://postgr.es/m/11d531fe-52fc-c6ea-7e8e-62f1b6ec626e@gmail.com
2023-03-16 14:22:34 +09:00
Tom Lane 483bdb2afe Support [NO] INDENT option in XMLSERIALIZE().
This adds the ability to pretty-print XML documents ... according to
libxml's somewhat idiosyncratic notions of what's pretty, anyway.
One notable divergence from a strict reading of the spec is that
libxml is willing to collapse empty nodes "<node></node>" to just
"<node/>", whereas SQL and the underlying XML spec say that this
option should only result in whitespace tweaks.  Nonetheless,
it seems close enough to justify using the SQL-standard syntax.

Jim Jones, reviewed by Peter Smith and myself

Discussion: https://postgr.es/m/2f5df461-dad8-6d7d-4568-08e10608a69b@uni-muenster.de
2023-03-15 16:59:09 -04:00
Andrew Dunstan 419a8dd814 Add a hook for modifying the ldapbind password
The hook can be installed by a shared_preload library.

A similar mechanism could be used for radius paswords, for example, and
the type name auth_password_hook_typ has been shosen with that in mind.

John Naylor and Andrew Dunstan

Discussion: https://postgr.es/m/469b06ed-69de-ba59-c13a-91d2372e52a9@dunslane.net
2023-03-15 16:37:28 -04:00
Amit Kapila 89e46da5e5 Allow the use of indexes other than PK and REPLICA IDENTITY on the subscriber.
Using REPLICA IDENTITY FULL on the publisher can lead to a full table scan
per tuple change on the subscription when REPLICA IDENTITY or PK index is
not available. This makes REPLICA IDENTITY FULL impractical to use apart
from some small number of use cases.

This patch allows using indexes other than PRIMARY KEY or REPLICA
IDENTITY on the subscriber during apply of update/delete. The index that
can be used must be a btree index, not a partial index, and it must have
at least one column reference (i.e. cannot consist of only expressions).
We can uplift these restrictions in the future. There is no smart
mechanism to pick the index. If there is more than one index that
satisfies these requirements, we just pick the first one. We discussed
using some of the optimizer's low-level APIs for this but ruled it out
as that can be a maintenance burden in the long run.

This patch improves the performance in the vast majority of cases and the
improvement is proportional to the amount of data in the table. However,
there could be some regression in a small number of cases where the indexes
have a lot of duplicate and dead rows. It was discussed that those are
mostly impractical cases but we can provide a table or subscription level
option to disable this feature if required.

Author: Onder Kalaci, Amit Kapila
Reviewed-by: Peter Smith, Shi yu, Hou Zhijie, Vignesh C, Kuroda Hayato, Amit Kapila
Discussion: https://postgr.es/m/CACawEhVLqmAAyPXdHEPv1ssU2c=dqOniiGz7G73HfyS7+nGV4w@mail.gmail.com
2023-03-15 08:49:04 +05:30
Dean Rasheed d5d574146d Add support for the error functions erf() and erfc().
Expose the standard error functions as SQL-callable functions. These
are expected to be useful to people working with normal distributions,
and we use them here to test the distribution from random_normal().

Since these functions are defined in the POSIX and C99 standards, they
should in theory be available on all supported platforms. If that
turns out not to be the case, more work will be needed.

On all platforms tested so far, using extra_float_digits = -1 in the
regression tests is sufficient to allow for variations between
implementations. However, past experience has shown that there are
almost certainly going to be additional unexpected portability issues,
so these tests may well need further adjustments, based on the
buildfarm results.

Dean Rasheed, reviewed by Nathan Bossart and Thomas Munro.

Discussion: https://postgr.es/m/CAEZATCXv5fi7+Vu-POiyai+ucF95+YMcCMafxV+eZuN1B-=MkQ@mail.gmail.com
2023-03-14 09:17:36 +00:00
Michael Paquier 3a465cc678 libpq: Add support for require_auth to control authorized auth methods
The new connection parameter require_auth allows a libpq client to
define a list of comma-separated acceptable authentication types for use
with the server.  There is no negotiation: if the server does not
present one of the allowed authentication requests, the connection
attempt done by the client fails.

The following keywords can be defined in the list:
- password, for AUTH_REQ_PASSWORD.
- md5, for AUTH_REQ_MD5.
- gss, for AUTH_REQ_GSS[_CONT].
- sspi, for AUTH_REQ_SSPI and AUTH_REQ_GSS_CONT.
- scram-sha-256, for AUTH_REQ_SASL[_CONT|_FIN].
- creds, for AUTH_REQ_SCM_CREDS (perhaps this should be removed entirely
now).
- none, to control unauthenticated connections.

All the methods that can be defined in the list can be negated, like
"!password", in which case the server must NOT use the listed
authentication type.  The special method "none" allows/disallows the use
of unauthenticated connections (but it does not govern transport-level
authentication via TLS or GSSAPI).

Internally, the patch logic is tied to check_expected_areq(), that was
used for channel_binding, ensuring that an incoming request is
compatible with conn->require_auth.  It also introduces a new flag,
conn->client_finished_auth, which is set by various authentication
routines when the client side of the handshake is finished.  This
signals to check_expected_areq() that an AUTH_REQ_OK from the server is
expected, and allows the client to complain if the server bypasses
authentication entirely, with for example the reception of a too-early
AUTH_REQ_OK message.

Regression tests are added in authentication TAP tests for all the
keywords supported (except "creds", because it is around only for
compatibility reasons).  A new TAP script has been added for SSPI, as
there was no script dedicated to it yet.  It relies on SSPI being the
default authentication method on Windows, as set by pg_regress.

Author: Jacob Champion
Reviewed-by: Peter Eisentraut, David G. Johnston, Michael Paquier
Discussion: https://postgr.es/m/9e5a8ccddb8355ea9fa4b75a1e3a9edc88a70cd3.camel@vmware.com
2023-03-14 14:00:05 +09:00
Andrew Dunstan 9f8377f7a2 Add a DEFAULT option to COPY FROM
This allows for a string which if an input field matches causes the
column's default value to be inserted. The advantage of this is that
the default can be inserted in some rows and not others, for which
non-default data is available.

The file_fdw extension is also modified to take allow use of this
option.

Israel Barth Rubio

Discussion: https://postgr.es/m/CAO_rXXAcqesk6DsvioOZ5zmeEmpUN5ktZf-9=9yu+DTr0Xr8Uw@mail.gmail.com
2023-03-13 10:01:56 -04:00