This was useful before widespread Unicode adoption, and was based on the
internal encoding Emacs used to mix multiple sub-encodings. Emacs
itself has stopped using it, and our implementation hadn't been updated
with modern underlying standards. It is thought to be very unlikely
that anyone is still using it in the field. Since such a complex
encoding comes with costs and risks, we agreed to drop support.
Any existing database using this encoding would need to be dumped and
restored with a new encoding to upgrade to PostgreSQL 19, most likely
UTF8, since pg_upgrade would fail.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Tatsuo Ishii <ishii@postgresql.org>
Reviewed-by: Jeff Davis <pgsql@j-davis.com>
Discussion: https://postgr.es/m/CA%2BhUKGKXDXh-FdU0orjfv%2BF08f%3DD91BhV3Ra-4zL-q%2BJmGYqTA%40mail.gmail.com
This adds support to pg_test_timing for the different timing sources added by
294520c444.
Author: Lukas Fittl <lukas@fittl.com>
Author: David Geier <geidav.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: David Geier <geidav.pg@gmail.com>
Reviewed-by: Zsolt Parragi <zsolt.parragi@percona.com>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de> (in an earlier version)
Discussion: https://www.postgresql.org/message-id/flat/20200612232810.f46nbqkdhbutzqdg%40alap3.anarazel.de
Allows collecting details about AIO / prefetch for scan nodes backed by
a ReadStream. This may be enabled by a new "IO" option in EXPLAIN, and
it shows information about the prefetch distance and I/O requests.
As of this commit this applies only to BitmapHeapScan, because that's
the only scan node using a ReadStream and collecting instrumentation
from workers in a parallel query. Support for SeqScan and TidRangeScan,
the other scan nodes using ReadStream, will be added in subsequent
commits.
The stats are collected only when required by EXPLAIN ANALYZE, with the
IO option (disabled by default). The amount of collected statistics is
very limited, but we don't want to clutter EXPLAIN with too much data.
The IOStats struct is stored in the scan descriptor as a field, next to
other fields used by table AMs. A pointer to the field is passed to the
ReadStream, and updated directly.
It's the responsibility of the table AM to allocate the struct (e.g. in
ambeginscan) whenever the flag SO_SCAN_INSTRUMENT flag is passed to the
scan, so that the executor and ReadStream has access to it.
The collected stats are designed for ReadStream, but are meant to be
reasonably generic in case a TAM manages I/Os in different ways.
Author: Tomas Vondra <tomas@vondra.me>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Lukas Fittl <lukas@fittl.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/flat/a177a6dd-240b-455a-8f25-aca0b1c08c6e%40vondra.me
This allows the direct use of the Time-Stamp Counter (TSC) value retrieved
from the CPU using RDTSC/RDTSCP instructions, instead of APIs like
clock_gettime() on POSIX systems.
This reduces the overhead of EXPLAIN with ANALYZE and TIMING ON. Tests showed
that the overhead on top of actual runtime when instrumenting queries moving
lots of rows through the plan can be reduced from 2x as slow to 1.2x as slow
compared to the actual runtime. More complex workloads such as TPCH queries
have also shown ~20% gains when instrumented compared to before.
To control use of the TSC, the new "timing_clock_source" GUC is introduced,
whose default ("auto") automatically uses the TSC when reliable, for example
when running on modern Intel CPUs, or when running on Linux and the system
clocksource is reported as "tsc". The use of the operating system clock source
can be enforced by setting "system", or on x86-64 architectures the use of TSC
can be enforced by explicitly setting "tsc".
In order to use the TSC the frequency is first determined by use of CPUID, and
if not available, by running a short calibration loop at program start,
falling back to the system clock source if TSC values are not stable.
Note, that we split TSC usage into the RDTSC CPU instruction which does not
wait for out-of-order execution (faster, less precise) and the RDTSCP
instruction, which waits for outstanding instructions to retire. RDTSCP is
deemed to have little benefit in the typical InstrStartNode() /
InstrStopNode() use case of EXPLAIN, and can be up to twice as slow. To
separate these use cases, the new macro INSTR_TIME_SET_CURRENT_FAST() is
introduced, which uses RDTSC.
The original macro INSTR_TIME_SET_CURRENT() uses RDTSCP and is supposed to be
used when precision is more important than performance. When the system timing
clock source is used both of these macros instead utilize the system
APIs (clock_gettime / QueryPerformanceCounter) like before.
Additional users of interval timing, such as track_io_timing and
track_wal_io_timing could also benefit from being converted to use
INSTR_TIME_SET_CURRENT_FAST() but are left for future changes.
Author: Lukas Fittl <lukas@fittl.com>
Author: Andres Freund <andres@anarazel.de>
Author: David Geier <geidav.pg@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: David Geier <geidav.pg@gmail.com>
Reviewed-by: Lukas Fittl <lukas@fittl.com>
Reviewed-by: Zsolt Parragi <zsolt.parragi@percona.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com> (in an earlier version)
Reviewed-by: Maciek Sakrejda <m.sakrejda@gmail.com> (in an earlier version)
Reviewed-by: Robert Haas <robertmhaas@gmail.com> (in an earlier version)
Reviewed-by: Jakub Wartak <jakub.wartak@enterprisedb.com> (in an earlier version)
Discussion: https://postgr.es/m/20200612232810.f46nbqkdhbutzqdg@alap3.anarazel.de
OAuth validators can already use custom GUCs to configure behavior
globally. But we currently provide no ability to adjust settings for
individual HBA entries, because the original design focused on a world
where a provider covered a "single audience" of users for one database
cluster. This assumption does not apply to multitenant use cases, where
a single validator may be controlling access for wildly different user
groups.
To improve this use case, add two new API calls for use by validator
callbacks: RegisterOAuthHBAOptions() and GetOAuthHBAOption().
Registering options "foo" and "bar" allows a user to set "validator.foo"
and "validator.bar" in an oauth HBA entry. These options are stringly
typed (syntax validation is solely the responsibility of the defining
module), and names are restricted to a subset of ASCII to avoid tying
our hands with future HBA syntax improvements.
Unfortunately, we can't check the custom option names during a reload of
the configuration, like we do with standard HBA options, without
requiring all validators to be loaded via shared_preload_libraries.
(I consider this to be a nonstarter: most validators should probably use
session_preload_libraries at most, since requiring a full restart just
to update authentication behavior will be unacceptable to many users.)
Instead, the new validator.* options are checked against the registered
list at connection time.
Multiple alternatives were proposed and/or prototyped, including
extending the GUC system to allow per-HBA overrides, joining forces with
recent refactoring work on the reloptions subsystem, and giving the
ability to customize HBA options to all PostgreSQL extensions. I
personally believe per-HBA GUC overrides are the best option, because
several existing GUCs like authentication_timeout and pre_auth_delay
would fit there usefully. But the recent addition of SNI per-host
settings in 4f433025f indicates that a more general solution is needed,
and I expect that to take multiple releases' worth of discussion.
This compromise patch, then, is intentionally designed to be an
architectural dead end: simple to describe, cheap to maintain, and
providing just enough functionality to let validators move forward for
PG19. The hope is that it will be replaced in the future by a solution
that can handle per-host, per-HBA, and other per-context configuration
with the same functionality that GUCs provide today. In the meantime,
the bulk of the code in this patch consists of strict guardrails on the
simple API, to try to ensure that we don't have any reason to regret its
existence during its unknown lifespan.
I owe particular thanks here to Zsolt Parragi, who prototyped several
approaches that guided the final design.
Suggested-by: Zsolt Parragi <zsolt.parragi@percona.com>
Suggested-by: VASUKI M <vasukianand0119@gmail.com>
Reviewed-by: Zsolt Parragi <zsolt.parragi@percona.com>
Discussion: https://postgr.es/m/CAN4CZFM3b8u5uNNNsY6XCya257u%2BDofms3su9f11iMCxvCacag%40mail.gmail.com
PGOAUTHDEBUG is a blunt instrument: you get all the debugging features,
or none of them. The most annoying consequence during manual use is the
Curl debug trace, which tends to obscure the device flow prompt
entirely. The promotion of PGOAUTHCAFILE into its own feature in
993368113 improved the situation somewhat, but there's still the
discomfort of knowing you have to opt into many dangerous behaviors just
to get the single debug feature you wanted.
Explode the PGOAUTHDEBUG syntax into a comma-separated list. The old
"UNSAFE" value enables everything, like before. Any individual unsafe
features still require the envvar to begin with an "UNSAFE:" prefix, to
try to interrupt the flow of someone who is about to do something they
should not.
So now, rather than
PGOAUTHDEBUG=UNSAFE # enable all the unsafe things
a developer can say
PGOAUTHDEBUG=call-count # only show me the call count. safe!
PGOAUTHDEBUG=UNSAFE:trace # print secrets, but don't allow HTTP
To avoid adding more build system scaffolding to libpq-oauth, implement
this entirely in a small private header. This unfortunately can't be
standalone, so it needs a headerscheck exception.
Author: Zsolt Parragi <zsolt.parragi@percona.com>
Co-authored-by: Jacob Champion <jacob.champion@enterprisedb.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Zsolt Parragi <zsolt.parragi@percona.com>
Discussion: https://postgr.es/m/CAOYmi%2B%3DfbZNJSkHVci%3DGpR8XPYObK%3DH%2B2ERRha0LDTS%2BifsWnw%40mail.gmail.com
Discussion: https://postgr.es/m/CAN4CZFMmDZMH56O9vb_g7vHqAk8ryWFxBMV19C39PFghENg8kA%40mail.gmail.com
Add a new GUC max_repack_replication_slots, which lets the user reserve
some additional replication slots for concurrent repack (and only
concurrent repack). With this, the user doesn't have to worry about
changing the max_replication_slots in order to cater for use of
concurrent repack.
(We still use the same pool of bgworkers though, but that's less
commonly a problem than slots.)
Author: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Srinath Reddy Sadipiralla <srinath2133@gmail.com>
Discussion: https://postgr.es/m/202604012148.nnnmyxxrr6nh@alvherre.pgsql
If pg_stash_advice.persist = true, stashed advice will be written to
pg_stash_advice.tsv in the data directory, periodically and at
shutdown. On restart, stash modifications are locked out until this
file has been reloaded, but queries will not be, so there may be a
short window after startup during which previously-stashed advice is
not automatically applied.
Author: Robert Haas <rhaas@postgresql.org>
Co-authored-by: Lukas Fittl <lukas@fittl.com>
Discussion: https://postgr.es/m/CA+Tgmob87qsWa-VugofU6epuV0H5XjWZGMbQas4Q-ADKmvSyBg@mail.gmail.com
By default, the logical decoding assumes access to shared catalogs, so
the snapshot builder needs to consider cluster-wide XIDs during startup.
That in turn means that, if any transaction is already running (and has
XID assigned), the snapshot builder needs to wait for its completion, as
it does not know if that transaction performed catalog changes earlier.
A possible problem with this concept is that if REPACK (CONCURRENTLY) is
running in some database, backends running the same command in other
databases get stuck until the first one has committed. Thus only a
single backend in the cluster can run REPACK (CONCURRENTLY) at any time.
Likewise, REPACK (CONCURRENTLY) can block walsenders starting on behalf
of subscriptions throughout the cluster.
This patch adds a new option to logical replication output plugin, to
declare that it does not use shared catalogs (i.e. catalogs that can be
changed by transactions running in other databases in the cluster). In
that case, no snapshot the backend will use during the decoding needs to
contain information about transactions running in other databases. Thus
the snapshot builder only needs to wait for completion of transactions
in the current database.
Currently we only use this option in the REPACK background worker. It
could possibly be used in the plugin for logical replication too,
however that would need thorough analysis of that plugin.
Bump WAL version number, due to a new field in xl_running_xacts.
Author: Antonin Houska <ah@cybertec.at>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Discussion: https://postgr.es/m/90475.1775218118@localhost
This view contains one row for each table in the current database,
showing the current autovacuum scores for that specific table. It
also shows whether autovacuum would vacuum or analyze the table.
Bumps catversion.
Author: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Satyanarayana Narlapuram <satyanarlapuram@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Robert Treat <rob@xzilla.net>
Discussion: https://postgr.es/m/CAA5RZ0s4xjMrB-VAnLccC7kY8d0-4806-Lsac-czJsdA1LXtAw%40mail.gmail.com
When this flag is specified, REPACK no longer acquires access-exclusive
lock while the new copy of the table is being created; instead, it
creates the initial copy under share-update-exclusive lock only (same as
vacuum, etc), and it follows an MVCC snapshot; it sets up a replication
slot starting at that snapshot, and uses a concurrent background worker
to do logical decoding starting at the snapshot to populate a stash of
concurrent data changes. Those changes can then be re-applied to the
new copy of the table just before swapping the relfilenodes.
Applications can continue to access the original copy of the table
normally until just before the swap, which is the only point at which
the access-exclusive lock is needed.
There are some loose ends in this commit:
1. concurrent repack needs its own replication slot in order to apply
logical decoding, which are a scarce resource and easy to run out of.
2. due to the way the historic snapshot is initially set up, only one
REPACK process can be running at any one time on the whole system.
3. there's a danger of deadlocking (and thus abort) due to the lock
upgrade required at the final phase.
These issues will be addressed in upcoming commits.
The design and most of the code are by Antonin Houska, heavily based on
his own pg_squeeze third-party implementation.
Author: Antonin Houska <ah@cybertec.at>
Co-authored-by: Mihail Nikalayeu <mihailnikalayeu@gmail.com>
Co-authored-by: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Matthias van de Meent <boekewurm+postgres@gmail.com>
Reviewed-by: Srinath Reddy Sadipiralla <srinath2133@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Robert Treat <rob@xzilla.net>
Reviewed-by: Noriyoshi Shinoda <noriyoshi.shinoda@hpe.com>
Reviewed-by: vignesh C <vignesh21@gmail.com>
Discussion: https://postgr.es/m/5186.1706694913@antos
Discussion: https://postgr.es/m/202507262156.sb455angijk6@alvherre.pgsql
Add a note to the WAIT FOR documentation explaining that sessions
using this command on a standby server may be interrupted by recovery
conflicts. Some conflicts are unavoidable - for example, replaying
a tablespace drop terminates all backends unconditionally.
Discussion: https://postgr.es/m/CAPpHfds7oSCbZqob7ytT_Lso8fv-NW8LnedUTE4Krde%2B3rkJeA%40mail.gmail.com
Author: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Xuneng Zhou <xunengzhou@gmail.com>
The associated value should look like something that could be
part of an EXPLAIN options list, but restricted to EXPLAIN options
added by extensions.
For example, if pg_overexplain is loaded, you could set
auto_explain.log_extension_options = 'DEBUG, RANGE_TABLE'.
You can also specify arguments to these options in the same manner
as normal e.g. 'DEBUG 1, RANGE_TABLE false'.
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Reviewed-by: Lukas Fittl <lukas@fittl.com>
Discussion: http://postgr.es/m/CA+Tgmob-0W8306mvrJX5Urtqt1AAasu8pi4yLrZ1XfwZU-Uj1w@mail.gmail.com
Having rejected the principle that we should know how to re-order
the sub-commands of CREATE SCHEMA, there is not really anything
except a little coding to stop us from supporting more object types.
This patch adds support for creating functions (including procedures
and aggregates), operators, types (including domains), collations,
and text search objects.
SQL:2021 specifies that we should allow functions, procedures,
types, domains, and collations, so this moves us a great deal
closer to full SQL compatibility of CREATE SCHEMA. What remains
missing from their list are casts, transforms, roles, and some
object types we don't support yet (e.g. CREATE CHARACTER SET).
Supporting casts or transforms would be problematic because
they don't have names at all, let alone schema-qualified names,
so it'd be quite a stretch to say that they belong to a schema.
Roles likewise are not schema-qualified, plus they are global
to a cluster, making it even less reasonable to consider them
as belonging to a schema. So I don't see us trying to complete
the list.
User-defined aggregates and operators are outside the spec's ken,
as are text search objects, so adding them does not do anything for
spec compatibility. But they go along with these other object types,
plus it takes no additional code to support them since they are
represented as DefineStmts like some variants of CREATE TYPE.
It would indeed take some effort to reject them.
Author: Kirill Reshke <reshkekirill@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CALdSSPh4jUSDsWu3K58hjO60wnTRR0DuO4CKRcwa8EVuOSfXxg@mail.gmail.com
The previous patch simplified CREATE SCHEMA's behavior to "execute all
subcommands in the order they are written". However, that's a bit too
simple, as the spec clearly requires forward references in foreign key
constraint clauses to work, see feature F311-01. (Most other SQL
implementations seem to read more into the spec than that, but it's
not clear that there's justification for more in the text, and this is
the only case that doesn't introduce unresolvable issues.) We never
implemented that before, but let's do so now.
To fix it, transform FOREIGN KEY clauses into ALTER TABLE ... ADD
FOREIGN KEY commands and append them to the end of the CREATE SCHEMA's
subcommand list. This works because the foreign key constraints are
independent and don't affect any other DDL that might be in CREATE
SCHEMA. For simplicity, we do this for all FOREIGN KEY clauses even
if they would have worked where they were.
Author: Jian He <jian.universality@gmail.com>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/1075425.1732993688@sss.pgh.pa.us
transformCreateSchemaStmtElements has always believed that it is
supposed to re-order the subcommands of CREATE SCHEMA into a safe
execution order. However, it is nowhere near being capable of doing
that correctly. Nor is there reason to think that it ever will be,
or that that is a well-defined requirement. (The SQL standard does
say that it should be possible to do foreign-key forward references
within CREATE SCHEMA, but it's not clear that the text requires
anything more than that.) Moreover, the problem will get worse as
we add more subcommand types. Let's just drop the whole idea and
execute the commands in the order given, which seems like a much
less astonishment-prone definition anyway. The foreign-key issue
will be handled in a follow-up patch.
This will result in a release-note-worthy incompatibility,
which is that forward references like
CREATE SCHEMA myschema
CREATE VIEW myview AS SELECT * FROM mytable
CREATE TABLE mytable (...);
used to work and no longer will. Considering how many closely
related variants never worked, this isn't much of a loss.
Along the way, pass down a ParseState so that we can provide an
error cursor for "wrong schema name" and related errors, and fix
transformCreateSchemaStmtElements so that it doesn't scribble
on the parsetree passed to it.
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Kirill Reshke <reshkekirill@gmail.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
Discussion: https://postgr.es/m/1075425.1732993688@sss.pgh.pa.us
Previously, autovacuum always disabled parallel vacuum regardless of
the table's index count or configuration. This commit enables
autovacuum workers to use parallel index vacuuming and index cleanup,
using the same parallel vacuum infrastructure as manual VACUUM.
Two new configuration options control the feature. The GUC
autovacuum_max_parallel_workers sets the maximum number of parallel
workers a single autovacuum worker may launch; it defaults to 0,
preserving existing behavior unless explicitly enabled. The per-table
storage parameter autovacuum_parallel_workers provides per-table
limits. A value of 0 disables parallel vacuum for the table, a
positive value caps the worker count (still bounded by the GUC), and
-1 (the default) defers to the GUC.
To handle cases where autovacuum workers receive a SIGHUP and update
their cost-based vacuum delay parameters mid-operation, a new
propagation mechanism is added to vacuumparallel.c. The leader stores
its effective cost parameters in a DSM segment. Parallel vacuum
workers poll for changes in vacuum_delay_point(); if an update is
detected, they apply the new values locally via VacuumUpdateCosts().
A new test module, src/test/modules/test_autovacuum, is added to
verify that parallel autovacuum workers are correctly launched and
that cost-parameter updates are propagated as expected.
The patch was originally proposed by Maxim Orlov, but the
implementation has undergone significant architectural changes
since then during the review process.
Author: Daniil Davydov <3danissimo@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Matheus Alcantara <matheusssilv97@gmail.com>
Reviewed-by: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: zengman <zengman@halodbtech.com>
Discussion: https://postgr.es/m/CACG=ezZOrNsuLoETLD1gAswZMuH2nGGq7Ogcc0QOE5hhWaw=cw@mail.gmail.com
This module allows plan advice strings to be provided automatically
from an in-memory advice stash. Advice stashes are stored in dynamic
shared memory and must be recreated and repopulated after a server
restart. If pg_stash_advice.stash_name is set to the name of an advice
stash, and if query identifiers are enabled, the query identifier
for each query will be looked up in the advice stash and the
associated advice string, if any, will be used each time that query
is planned.
Reviewed-by: Lukas Fittl <lukas@fittl.com>
Reviewed-by: Alexandra Wang <alexandra.wang.oss@gmail.com>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Reviewed-by: Jakub Wartak <jakub.wartak@enterprisedb.com>
Discussion: http://postgr.es/m/CA+TgmoaeNuHXQ60P3ZZqJLrSjP3L1KYokW9kPfGbWDyt+1t=Ng@mail.gmail.com
Previously, during shutdown, walsenders always waited until all pending data
was replicated to receivers. This ensures sender and receiver stay in sync
after shutdown, which is important for physical replication switchovers,
but it can significantly delay shutdown. For example, in logical replication,
if apply workers are blocked on locks, walsenders may wait until those locks
are released, preventing shutdown from completing for a long time.
This commit introduces a new GUC, wal_sender_shutdown_timeout,
which specifies the maximum time a walsender waits during shutdown for all
pending data to be replicated. When set, shutdown completes once all data is
replicated or the timeout expires. A value of -1 (the default) disables
the timeout.
This can reduce shutdown time when replication is slow or stalled. However,
if the timeout is reached, the sender and receiver may be left out of sync,
which can be problematic for physical replication switchovers.
Author: Andrey Silitskiy <a.silitskiy@postgrespro.ru>
Author: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Takamichi Osumi <osumi.takamichi@fujitsu.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Greg Sabino Mullane <htamfids@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Vitaly Davydov <v.davydov@postgrespro.ru>
Reviewed-by: Ronan Dunklau <ronan@dunklau.fr>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Japin Li <japinli@hotmail.com>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/TYAPR01MB586668E50FC2447AD7F92491F5E89@TYAPR01MB5866.jpnprd01.prod.outlook.com
This replaces the [Subsystem]ShmemSize() and [Subsystem]ShmemInit()
functions called at postmaster startup with a new set of callbacks.
The new mechanism is designed to be more ergonomic. Notably, the size
of each shmem area is specified in the same ShmemRequestStruct() call,
together with its name. The same mechanism is used in extensions,
replacing the shmem_{request/startup}_hooks.
ShmemInitStruct() and ShmemInitHash() become backwards-compatibility
wrappers around the new functions. In future commits, I will replace
all ShmemInitStruct() and ShmemInitHash() calls with the new
functions, although we'll still need to keep them around for
extensions.
Co-authored-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Matthias van de Meent <boekewurm+postgres@gmail.com>
Reviewed-by: Zsolt Parragi <zsolt.parragi@percona.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://www.postgresql.org/message-id/CAExHW5vM1bneLYfg0wGeAa=52UiJ3z4vKd3AJ72X8Fw6k3KKrg@mail.gmail.com
The two new functions allow to extract the block number and offset from a tid.
There are existing ways to do so (e.g. by doing (ctid::text::point)[0]), but
they are hard to remember and not pretty.
tid_block() returns int8 (bigint) because BlockNumber is uint32, which exceeds
the range of int4. tid_offset() returns int4 (integer) because OffsetNumber is
uint16, which fits safely in int4.
Bumps catversion.
Author: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Discussion: https://postgr.es/m/CAJTYsWUzok2+mvSYkbVUwq_SWWg-GdHqCuYumN82AU97SjwjCA@mail.gmail.com
Add a new SQL-callable function that returns the DDL statements needed
to recreate a database. It takes a regdatabase argument and an optional
VARIADIC text argument for options that are specified as alternating
name/value pairs. The following options are supported: pretty (boolean)
for formatted output, owner (boolean) to include OWNER and tablespace
(boolean) to include TABLESPACE. The return is one or multiple rows
where the first row is a CREATE DATABASE statement and subsequent rows are
ALTER DATABASE statements to set some database properties.
The caller must have CONNECT privilege on the target database.
Author: Akshay Joshi <akshay.joshi@enterprisedb.com>
Co-authored-by: Andrew Dunstan <andrew@dunslane.net>
Co-authored-by: Euler Taveira <euler@eulerto.com>
Reviewed-by: Japin Li <japinli@hotmail.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Quan Zongliang <quanzongliang@yeah.net>
Discussion: https://postgr.es/m/CANxoLDc6FHBYJvcgOnZyS+jF0NUo3Lq_83-rttBuJgs9id_UDg@mail.gmail.com
Discussion: https://postgr.es/m/e247c261-e3fb-4810-81e0-a65893170e94@dunslane.net
Add a new SQL-callable function that returns the DDL statements needed
to recreate a tablespace. It takes a tablespace name or OID and an
optional VARIADIC text argument for options that are specified as
alternating name/value pairs. The following options are supported: pretty
(boolean) for formatted output and owner (boolean) to include OWNER.
(It includes two variants because there is no regtablespace pseudotype.)
The return is one or multiple rows where the first row is a CREATE
TABLESPACE statement and subsequent rows are ALTER TABLESPACE statements
to set some tablespace properties.
The caller must have SELECT privilege on pg_tablespace.
get_reloptions() in ruleutils.c is made non-static so it can be called
from the new ddlutils.c file.
Author: Nishant Sharma <nishant.sharma@enterprisedb.com>
Author: Manni Wood <manni.wood@enterprisedb.com>
Co-authored-by: Andrew Dunstan <andrew@dunslane.net>
Co-authored-by: Euler Taveira <euler@eulerto.com>
Reviewed-by: Jim Jones <jim.jones@uni-muenster.de>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Discussion: https://postgr.es/m/CAKWEB6rmnmGKUA87Zmq-s=b3Scsnj02C0kObQjnbL2ajfPWGEw@mail.gmail.com
Discussion: https://postgr.es/m/e247c261-e3fb-4810-81e0-a65893170e94@dunslane.net
Add a new SQL-callable function that returns the DDL statements needed
to recreate a role. It takes a regrole argument and an optional VARIADIC
text argument for options that are specified as alternating name/value
pairs. The following options are supported: pretty (boolean) for
formatted output and memberships (boolean) to include GRANT statements
for role memberships and membership options. The return is one or
multiple rows where the first row is a CREATE ROLE statement and
subsequent rows are ALTER ROLE statements to set some role properties.
Password information is never included in the output.
The caller must have SELECT privilege on pg_authid.
Author: Mario Gonzalez <gonzalemario@gmail.com>
Author: Bryan Green <dbryan.green@gmail.com>
Co-authored-by: Andrew Dunstan <andrew@dunslane.net>
Co-authored-by: Euler Taveira <euler@eulerto.com>
Reviewed-by: Japin Li <japinli@hotmail.com>
Reviewed-by: Quan Zongliang <quanzongliang@yeah.net>
Reviewed-by: jian he <jian.universality@gmail.com>
Discussion: https://postgr.es/m/4c5f895e-3281-48f8-b943-9228b7da6471@gmail.com
Discussion: https://postgr.es/m/e247c261-e3fb-4810-81e0-a65893170e94@dunslane.net
READ ONLY transactions should prevent modifications to foreign data as
well as local data, but postgres_fdw transactions declared as READ ONLY
that reference foreign tables mapped to a remote view executing volatile
functions would modify data on remote servers, as it would open remote
transactions in READ WRITE mode.
Similarly, DEFERRABLE transactions should not abort due to a
serialization failure even when accessing foreign data, but postgres_fdw
transactions declared as DEFERRABLE would abort due to that failure in a
remote server, as it would open remote transactions in NOT DEFERRABLE
mode.
To fix, modify postgres_fdw to open remote transactions in the same
access/deferrable modes as the local transaction. This commit also
modifies it to open remote subtransactions in the same access mode as
the local subtransaction.
This commit changes the behavior of READ ONLY/DEFERRABLE transactions
using postgres_fdw; in particular, it doesn't allow the READ ONLY
transactions to modify data on remote servers anymore, so such
transactions should be redeclared as READ WRITE or rewritten using other
tools like dblink. The release notes should note this as an
incompatibility.
These issues exist since the introduction of postgres_fdw, but to avoid
the incompatibility in the back branches, fix them in master only.
Author: Etsuro Fujita <etsuro.fujita@gmail.com>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Fujii Masao <masao.fujii@gmail.com>
Discussion: https://postgr.es/m/CAPmGK16n_hcUUWuOdmeUS%2Bw4Q6dZvTEDHb%3DOP%3D5JBzo-M3QmpQ%40mail.gmail.com
Discussion: https://postgr.es/m/E1uLe9X-000zsY-2g%40gemulon.postgresql.org
At the moment, the only way for a validator module to report error
details on failure is to log them separately before returning from
validate_cb. Independently of that problem, the ereport() calls that we
make during validation failure partially duplicate some of the work of
auth_failed().
The end result is overly verbose and confusing for readers of the logs:
[768233] LOG: [my_validator] bad signature in bearer token
[768233] LOG: OAuth bearer authentication failed for user "jacob"
[768233] DETAIL: Validator failed to authorize the provided token.
[768233] FATAL: OAuth bearer authentication failed for user "jacob"
[768233] DETAIL: Connection matched file ".../pg_hba.conf" line ...
Solve both problems by making use of the existing logdetail pointer
that's provided by ClientAuthentication. Validator modules may set
ValidatorModuleResult->error_detail to override our default generic
message.
The end result looks something like
[242284] FATAL: OAuth bearer authentication failed for user "jacob"
[242284] DETAIL: [my_validator] bad signature in bearer token
Connection matched file ".../pg_hba.conf" line ...
Reported-by: Álvaro Herrera <alvherre@kurilemu.de>
Reported-by: Zsolt Parragi <zsolt.parragi@percona.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Zsolt Parragi <zsolt.parragi@percona.com>
Discussion: https://postgr.es/m/202601241015.y5uvxd7oxnfs%40alvherre.pgsql
This allows data checksums to be enabled, or disabled, in a running
cluster without restricting access to the cluster during processing.
Data checksums could prior to this only be enabled during initdb or
when the cluster is offline using the pg_checksums app. This commit
introduce functionality to enable, or disable, data checksums while
the cluster is running regardless of how it was initialized.
A background worker launcher process is responsible for launching a
dynamic per-database background worker which will mark all buffers
dirty for all relation with storage in order for them to have data
checksums calculated on write. Once all relations in all databases
have been processed, the data_checksums state will be set to on and
the cluster will at that point be identical to one which had data
checksums enabled during initialization or via offline processing.
When data checksums are being enabled, concurrent I/O operations
from backends other than the data checksums worker will write the
checksums but not verify them on reading. Only when all backends
have absorbed the procsignalbarrier for setting data_checksums to
on will they also start verifying checksums on reading. The same
process is repeated during disabling; all backends write checksums
but do not verify them until the barrier for setting the state to
off has been absorbed by all. This in-progress state is used to
ensure there are no false negatives (or positives) due to reading
a checksum which is not in sync with the page.
A new testmodule, test_checksums, is introduced with an extensive
set of tests covering both online and offline data checksum mode
changes. The tests which run concurrent pgbdench during online
processing are gated behind the PG_TEST_EXTRA flag due to being
very expensive to run. Two levels of PG_TEST_EXTRA flags exist
to turn on a subset of the expensive tests, or the full suite of
multiple runs.
This work is based on an earlier version of this patch which was
reviewed by among others Heikki Linnakangas, Robert Haas, Andres
Freund, Tomas Vondra, Michael Banck and Andrey Borodin. During
the work on this new version, Tomas Vondra has given invaluable
assistance with not only coding and reviewing but very in-depth
testing.
Author: Daniel Gustafsson <daniel@yesql.se>
Author: Magnus Hagander <magnus@hagander.net>
Co-authored-by: Tomas Vondra <tomas@vondra.me>
Reviewed-by: Tomas Vondra <tomas@vondra.me>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://postgr.es/m/CABUevExz9hUUOLnJVr2kpw9Cx=o4MCr1SVKwbupzuxP7ckNutA@mail.gmail.com
Discussion: https://postgr.es/m/20181030051643.elbxjww5jjgnjaxg@alap3.anarazel.de
Discussion: https://postgr.es/m/CABUevEwE3urLtwxxqdgd5O2oQz9J717ZzMbh+ziCSa5YLLU_BA@mail.gmail.com
The previous commits reduced the amount of memory available for locks
by eliminating the "safety margins" and by settling the split between
LOCK and PROCLOCK tables at startup. The allocation is now more
deterministic, but it also means that you often hit one of the limits
sooner than before. To compensate for that, bump up
max_locks_per_transactions from 64 to 128. With that there is a little
more space in the both hash tables than what was the effective maximum
size for either table before the previous commits.
This only changes the default, so if you had changed
max_locks_per_transactions in postgresql.conf, you will still have
fewer locks available than before for the same setting value. This
should be noted in the release notes. A good rule of thumb is that if
you double max_locks_per_transactions, you should be able to get as
many locks as before.
Reviewed-by: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://www.postgresql.org/message-id/e07be2ba-856b-4ff5-8313-8b58b6b4e4d0@iki.fi
Add the following jsonpath methods:
* l/r/btrim()
* lower(), upper()
* initcap()
* replace()
* split_part()
Each simply dispatches to the standard string processing functions.
These depend on the locale, but since it's set at `initdb`, they can be
considered immutable and therefore allowed in any jsonpath expression.
Author: Florents Tselai <florents.tselai@gmail.com>
Co-authored-by: David E. Wheeler <david@justatheory.com>
Reviewed-by: Chao Li <li.evan.chao@gmail.com>
Reviewed-by: Andrew Dunstan <andrew@dunslane.net>
Discussion: https://postgr.es/m/CA+v5N40sJF39m0v7h=QN86zGp0CUf9F1WKasnZy9nNVj_VhCZQ@mail.gmail.com
While JIT can speed up large analytical queries, it can also cause
serious performance issues on otherwise very fast queries. Compiling
and optimizing the expressions may be so expensive, it completely
outweighs the JIT benefits for shorter queries.
Ideally, we'd address this in the cost model, but the part deciding
whether to enable JIT for a query is rather simple, partially because we
don't have any reliable estimates of how expensive the LLVM compilation
and optimization is.
Sometimes seemingly unrelated changes (for example a couple additional
INSERTs into a table) increase the cost just enough to enable JIT,
resulting in a performance cliff.
Because of these risks, most large-scale deployments already disable JIT
by default. Notably, this includes all hyperscalers.
This commit changes our default to align with that established practice.
If we improve the JIT (be it better costing or cheaper execution), we
can consider enabling it by default again.
Author: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://postgr.es/m/DG1VZJEX1AQH.2EH4OKGRUDB71@jeltef.nl
This is an extension of the UPDATE and DELETE commands to do a
"temporal update/delete" based on a range or multirange column. The
user can say UPDATE t FOR PORTION OF valid_at FROM '2001-01-01' TO
'2002-01-01' SET ... (or likewise with DELETE) where valid_at is a
range or multirange column.
The command is automatically limited to rows overlapping the targeted
portion, and only history within those bounds is changed. If a row
represents history partly inside and partly outside the bounds, then
the command truncates the row's application time to fit within the
targeted portion, then it inserts one or more "temporal leftovers":
new rows containing all the original values, except with the
application-time column changed to only represent the untouched part
of history.
To compute the temporal leftovers that are required, we use the *_minus_multi
set-returning functions defined in 5eed8ce50c.
- Added bison support for FOR PORTION OF syntax. The bounds must be
constant, so we forbid column references, subqueries, etc. We do
accept functions like NOW().
- Added logic to executor to insert new rows for the "temporal
leftover" part of a record touched by a FOR PORTION OF query.
- Documented FOR PORTION OF.
- Added tests.
Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://www.postgresql.org/message-id/flat/ec498c3d-5f2b-48ec-b989-5561c8aa2024%40illuminatedcomputing.com
This allows both univariate and multivariate statistics to be built on
virtual generated columns and expressions that refer to virtual
generated columns. The restriction disallowing extended statistics on
a single column is lifted in the case of a single virtual generated
column, since it is treated as a single expression.
In the catalogs, references to virtual generated columns are stored
as-is. They are expanded at ANALYZE time to build the statistics, and
at planning time to allow the optimizer to make use of the statistics.
This allows the statistics to be correctly rebuilt using ANALYZE, if a
column's generation expression is altered (which causes any existing
statistics data to be deleted).
Author: Yugo Nagata <nagata@sraoss.co.jp>
Reviewed-by: Dean Rasheed <dean.a.rasheed@gmail.com>
Discussion: https://postgr.es/m/20250422181006.dd6f9d1d81299f5b2ad55e1a@sraoss.co.jp
If the archive file was made with --no-schema or related options
then it likely does not have enough dependency information to
ensure that parallel restore will choose a workable restore order.
Document this.
In passing, do some minor wordsmithing on new nearby text about
restoring from pg_dumpall archives.
Author: vaibhave postgres <postgresvaibhave@gmail.com>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAM_eQjzTLtt1X9WKvMV6Rew0UvxT3mmhimZa9WT-vqaPjmXk-g@mail.gmail.com
This is nonsense on its face, since the textsearch parsing logic
generally uses int32 to count words (see, eg, struct ParsedText).
Not to mention that we don't support input strings larger than
1GB.
The actual limitation of interest is documented nearby: a tsvector
can't be larger than 1MB, thanks to 20-bit offset fields within it
(see WordEntry.pos). That constrains us to well under 256K lexemes
per tsvector, depending on how many positions are stored per lexeme.
It seems sufficient therefore to just remove the bit about number
of lexemes.
Author: Dharin Shah <dharinshah95@gmail.com>
Discussion: https://postgr.es/m/CAOj6k6d0YO6AO-bhxkfUXPxUi-+YX9-doh2h5D5z0Bm8D2w=OA@mail.gmail.com
The docs previously didn't explain that leaf and non-leaf keys
could be treated differently, even though many of our opclasses
do exactly that. It also wasn't explained how that relates to
the STORAGE option, particularly since only one storage type
can be specified for both leaf and non-leaf keys.
While here, reorganize the text slightly, rather than sticking
additional detail into what's supposed to be a brief summary
paragraph.
Author: Paul A Jungwirth <pj@illuminatedcomputing.com>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA+renyWs5Np+FLSYfL+eu20S4U671A3fQGb-+7e22HLrD1NbYw@mail.gmail.com
Adjust the syntax of the EXCEPT clause in CREATE/ALTER PUBLICATION
added in commits fd366065e0 and 493f8c6439 to move the TABLE keyword
inside the relation list.
Old syntax:
CREATE PUBLICATION ... FOR ALL TABLES EXCEPT TABLE (t1, ...);
ALTER PUBLICATION ... SET ALL TABLES EXCEPT TABLE (t1, ...);
New syntax:
CREATE PUBLICATION ... FOR ALL TABLES EXCEPT (TABLE t1, ...);
ALTER PUBLICATION ... SET ALL TABLES EXCEPT (TABLE t1, ...);
This is to ensure that inclusion and exclusion list can be specified in
a same way. Previously, the exclusion table list can be specified as
TABLE (t1, t2, t3) and inclusion list can be specified as TABLE t1, t2,
t3, or TABLE t1, TABLE t2, TABLE t3.
This change is purely syntactic and does not alter behavior.
Reported-by: Masahiko Sawada <sawada.mshk@gmail.com>
Author: vignesh C <vignesh21@gmail.com>
Author: Shlok Kyal <shlok.kyal.oss@gmail.com>
Reviewed-by: shveta malik <shveta.malik@gmail.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Zhijie Hou <houzj.fnst@fujitsu.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: SATYANARAYANA NARLAPURAM <satyanarlapuram@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Discussion: https://postgr.es/m/CAD21AoCC8XuwfX62qKBSfHUAoww_XB3_84HjswgL9jxQy696yw@mail.gmail.com
Discussion: https://postgr.es/m/CALDaNm3=JrucjhiiwsYQw5-PGtBHFONa6F7hhWCXMsGvh=tamA@mail.gmail.com
We long ago folded these two tuple header fields into one field
to save space. However, nothing was done to the user-facing
documentation about them, perhaps with the idea that we'd add
code to emit something approximating the original definitions.
That never happened and presumably never will, so update the
text to reflect current reality.
Author: Paul A Jungwirth <pj@illuminatedcomputing.com>
Co-authored-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CA+renyVYYboiTayRRE0j1oKpeB+NjEBSUXfwgEu6O0JESSmauQ@mail.gmail.com
PG18 hid the PGOAUTHCAFILE envvar behind PGOAUTHDEBUG=UNSAFE, because I
thought that any "real" production usage of private CA certificates
would have them added to the Curl system trust store. But there are use
cases, such as containerized environments, that prefer to manage custom
CA settings more granularly; some of them consider envvar configuration
of certificates to be standard practice.
Move PGOAUTHCAFILE out from under the debug flag, and add an
oauth_ca_file option to libpq to configure trusted CAs per connection.
Patch by Jonathan Gonzalez V., with some additional wordsmithing and
test organization by me.
Author: Jonathan Gonzalez V. <jonathan.abdiel@gmail.com>
Co-authored-by: Jacob Champion <jacob.champion@enterprisedb.com>
Reviewed-by: Zsolt Parragi <zsolt.parragi@percona.com>
Discussion: https://postgr.es/m/16a91d02795cb991963326a902afa764e4d721db.camel%40gmail.com
In addition to removing the bits8, bits16, and bits32 typedefs,
this commit replaces all uses with uint8, uint16, or uint32. bits*
provided little benefit beyond establishing the intent of the
variable, and they were inconsistently used for that purpose.
Third-party code should instead use the corresponding uint*
typedef.
Suggested-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Álvaro Herrera <alvherre@kurilemu.de>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Dagfinn Ilmari Mannsåker <ilmari@ilmari.org>
Discussion: https://postgr.es/m/absbX33E4eaA0Ity%40nathan
Commit 121d774cae added text to master describing pruning-aware
locking behavior introduced by 525392d57. That behavior was
reverted in May 2025, making the text incorrect. Replace it with
the text used in back branches, which correctly describes current
behavior: pruned partitions are still locked at the beginning of
execution.
Discussion: https://postgr.es/m/CA+HiwqFT0fPPoYBr0iUFWNB-Og7bEXB9hB=6ogk_qD9=OM8Vbw@mail.gmail.com
Most of the pairs of incompatible options (such as --file and --dbname)
are pretty obvious and need no explanation. But it may not be obvious
that --single-transaction cannot be used together with --create or
multiple jobs, so let's mention that in the documentation.
Author: Ashutosh Bapat <ashutosh.bapat.oss@gmail.com>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Discussion: https://postgr.es/m/CAExHW5ti5igDwOOde6shgfS7JPtCY9gNrkB3xNr=FuGTYVDSjQ@mail.gmail.com
Add a sentence that describes the parts of a cluster's state that are
*not* included in the output.
Also swap two sentences in the introductory paragraph. Without that,
it is not clear what the "it" at the beginning of the second sentence
is referring to. Also add a reference to pg_restore, since not all
output formats are restored with pg_dump.
Also clarify the recently-added text about where different output
formats go, and relocate it above the ancillary text about having
to run as superuser.
Reported-by: Dimitre Radoulov <cichomitiko@gmail.com>
Author: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CAGJBphSX2oMPPu=VM4U8NP4+qffFH_483tFQCJ_s-mOcN3DLDw@mail.gmail.com
Create a <sect4> section for each function that the previous text
described in one long series of paragraphs. Also split the functions'
previously in-line syntax summaries into <synopsis> clauses, which is
more readable and allows us to sneak in an explicit mention of the
result data type.
This change gives us an opportunity to make cross-reference links
more specific, too, so do that.
Author: jian he <jian.universality@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/CACJufxFuk9P=P4=BZ=qCkgvo6im8aL8NnCkjxx2S2MQDWNdouw@mail.gmail.com
While fixing the base32hex UUID sortability test in commit
89210037a0, it turned out that the expected lexicographical order is
only maintained under the C collation (or an equivalent byte-wise
collation). Natural language collations may employ different rules,
breaking the sortability.
This commit updates the documentation to explicitly state that
base32hex is "byte-wise sortable", ensuring users do not fall into the
trap of using natural language collations when querying their encoded
data.
Co-Authored-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/CAD21AoAwX1D6baSGuQXm0mzPXPWB07kgaoaaahjNHHenbdY24A@mail.gmail.com
