This commit introduces idle_replication_slot_timeout GUC that allows
inactive slots to be invalidated at the time of checkpoint. Because
checkpoints happen checkpoint_timeout intervals, there can be some lag
between when the idle_replication_slot_timeout was exceeded and when the
slot invalidation is triggered at the next checkpoint. To avoid such lags,
users can force a checkpoint to promptly invalidate inactive slots.
Note that the idle timeout invalidation mechanism is not applicable for
slots that do not reserve WAL or for slots on the standby server that are
synced from the primary server (i.e., standby slots having 'synced' field
'true'). Synced slots are always considered to be inactive because they
don't perform logical decoding to produce changes.
The slots can become inactive for a long period if a subscriber is down
due to a system error or inaccessible because of network issues. If such a
situation persists, it might be more practical to recreate the subscriber
rather than attempt to recover the node and wait for it to catch up which
could be time-consuming.
Then, external tools could create replication slots (e.g., for migrations
or upgrades) that may fail to remove them if an error occurs, leaving
behind unused slots that take up space and resources. Manually cleaning
them up can be tedious and error-prone, and without intervention, these
lingering slots can cause unnecessary WAL retention and system bloat.
As the duration of idle_replication_slot_timeout is in minutes, any test
using that would be time-consuming. We are planning to commit a follow up
patch for tests by using the injection point framework.
Author: Nisha Moond <nisha.moond412@gmail.com>
Author: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: Hayato Kuroda <kuroda.hayato@fujitsu.com>
Reviewed-by: Vignesh C <vignesh21@gmail.com>
Reviewed-by: Amit Kapila <amit.kapila16@gmail.com>
Reviewed-by: Hou Zhijie <houzj.fnst@fujitsu.com>
Reviewed-by: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Discussion: https://postgr.es/m/CALj2ACW4aUe-_uFQOjdWCEN-xXoLGhmvRFnL8SNw_TZ5nJe+aw@mail.gmail.com
Discussion: https://postgr.es/m/OS0PR01MB5716C131A7D80DAE8CB9E88794FC2@OS0PR01MB5716.jpnprd01.prod.outlook.com
This commit improves the description of a couple of GUCs, to be more
consistent with the style of their surroundings:
* array_nulls
* enable_self_join_elimination
* optimize_bounded_sort
* row_security
* synchronize_seqscans
Author: Kyotaro Horiguchi
Discussion: https://postgr.es/m/20250218.103240.1422205966404509831.horikyota.ntt@gmail.com
The Self-Join Elimination (SJE) feature removes an inner join of a plain
table to itself in the query tree if it is proven that the join can be
replaced with a scan without impacting the query result. Self-join and
inner relation get replaced with the outer in query, equivalence classes,
and planner info structures. Also, the inner restrictlist moves to the
outer one with the removal of duplicated clauses. Thus, this optimization
reduces the length of the range table list (this especially makes sense for
partitioned relations), reduces the number of restriction clauses and,
in turn, selectivity estimations, and potentially improves total planner
prediction for the query.
This feature is dedicated to avoiding redundancy, which can appear after
pull-up transformations or the creation of an EquivalenceClass-derived clause
like the below.
SELECT * FROM t1 WHERE x IN (SELECT t3.x FROM t1 t3);
SELECT * FROM t1 WHERE EXISTS (SELECT t3.x FROM t1 t3 WHERE t3.x = t1.x);
SELECT * FROM t1,t2, t1 t3 WHERE t1.x = t2.x AND t2.x = t3.x;
In the future, we could also reduce redundancy caused by subquery pull-up
after unnecessary outer join removal in cases like the one below.
SELECT * FROM t1 WHERE x IN
(SELECT t3.x FROM t1 t3 LEFT JOIN t2 ON t2.x = t1.x);
Also, it can drastically help to join partitioned tables, removing entries
even before their expansion.
The SJE proof is based on innerrel_is_unique() machinery.
We can remove a self-join when for each outer row:
1. At most, one inner row matches the join clause;
2. Each matched inner row must be (physically) the same as the outer one;
3. Inner and outer rows have the same row mark.
In this patch, we use the next approach to identify a self-join:
1. Collect all merge-joinable join quals which look like a.x = b.x;
2. Add to the list above the baseretrictinfo of the inner table;
3. Check innerrel_is_unique() for the qual list. If it returns false, skip
this pair of joining tables;
4. Check uniqueness, proved by the baserestrictinfo clauses. To prove the
possibility of self-join elimination, the inner and outer clauses must
match exactly.
The relation replacement procedure is not trivial and is partly combined
with the one used to remove useless left joins. Tests covering this feature
were added to join.sql. Some of the existing regression tests changed due
to self-join removal logic.
Discussion: https://postgr.es/m/flat/64486b0b-0404-e39e-322d-0801154901f3%40postgrespro.ru
Author: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Author: Alexander Kuzmenkov <a.kuzmenkov@postgrespro.ru>
Co-authored-by: Alexander Korotkov <aekorotkov@gmail.com>
Co-authored-by: Alena Rybakina <lena.ribackina@yandex.ru>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Simon Riggs <simon@2ndquadrant.com>
Reviewed-by: Jonathan S. Katz <jkatz@postgresql.org>
Reviewed-by: David Rowley <david.rowley@2ndquadrant.com>
Reviewed-by: Thomas Munro <thomas.munro@enterprisedb.com>
Reviewed-by: Konstantin Knizhnik <k.knizhnik@postgrespro.ru>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Hywel Carver <hywel@skillerwhale.com>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: Ronan Dunklau <ronan.dunklau@aiven.io>
Reviewed-by: vignesh C <vignesh21@gmail.com>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Reviewed-by: Greg Stark <stark@mit.edu>
Reviewed-by: Jaime Casanova <jcasanov@systemguards.com.ec>
Reviewed-by: Michał Kłeczek <michal@kleczek.org>
Reviewed-by: Alena Rybakina <lena.ribackina@yandex.ru>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Many GUCs accept special values like -1 or an empty string to
disable the feature, use a system default, etc. While the
documentation consistently lists these special values, the GUC
descriptions do not. Many such descriptions fail to mention the
special values, and those that do vary in phrasing and placement.
This commit aims to bring some consistency to this area by applying
the following rules:
* Special values should be listed at the end of the long
description.
* Descriptions should use numerals (e.g., "0") instead of words
(e.g., "zero").
* Special value mentions should be concise and direct (e.g., "0
disables the timeout.", "An empty string means use the operating
system setting.").
* Multiple special values should be listed in ascending order.
Of course, there are exceptions, such as
max_pred_locks_per_relation and search_path, whose special values
are too complex to include. And there are cases like
listen_addresses, where the meaning of an empty string is arguably
too obvious to include. In those cases, I've refrained from adding
special value information to the GUC description.
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Reviewed-by: "David G. Johnston" <david.g.johnston@gmail.com>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Discussion: https://postgr.es/m/Z6aIy4aywxUZHAo6%40nathan
This commit adds the amount of time spent sleeping due to
cost-based delay to the pg_stat_progress_vacuum and
pg_stat_progress_analyze system views. A new configuration
parameter named track_cost_delay_timing, which is off by default,
controls whether this information is gathered. For vacuum, the
reported value includes the sleep time of any associated parallel
workers. However, parallel workers only report their sleep time
once per second to avoid overloading the leader process.
Bumps catversion.
Author: Bertrand Drouvot <bertranddrouvot.pg@gmail.com>
Co-authored-by: Nathan Bossart <nathandbossart@gmail.com>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Masahiro Ikeda <ikedamsh@oss.nttdata.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Sergei Kornilov <sk@zsrv.org>
Discussion: https://postgr.es/m/ZmaXmWDL829fzAVX%40ip-10-97-1-34.eu-west-3.compute.internal
Aggressive vacuums must scan every unfrozen tuple in order to advance
the relfrozenxid/relminmxid. Because data is often vacuumed before it is
old enough to require freezing, relations may build up a large backlog
of pages that are set all-visible but not all-frozen in the visibility
map. When an aggressive vacuum is triggered, all of these pages must be
scanned. These pages have often been evicted from shared buffers and
even from the kernel buffer cache. Thus, aggressive vacuums often incur
large amounts of extra I/O at the expense of foreground workloads.
To amortize the cost of aggressive vacuums, eagerly scan some
all-visible but not all-frozen pages during normal vacuums.
All-visible pages that are eagerly scanned and set all-frozen in the
visibility map are counted as successful eager freezes and those not
frozen are counted as failed eager freezes.
If too many eager scans fail in a row, eager scanning is temporarily
suspended until a later portion of the relation. The number of failures
tolerated is configurable globally and per table.
To effectively amortize aggressive vacuums, we cap the number of
successes as well. Capping eager freeze successes also limits the amount
of potentially wasted work if these pages are modified again before the
next aggressive vacuum. Once we reach the maximum number of blocks
successfully eager frozen, eager scanning is disabled for the remainder
of the vacuum of the relation.
Original design idea from Robert Haas, with enhancements from
Andres Freund, Tomas Vondra, and me
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Robert Treat <rob@xzilla.net>
Reviewed-by: Bilal Yavuz <byavuz81@gmail.com>
Discussion: https://postgr.es/m/flat/CAAKRu_ZF_KCzZuOrPrOqjGVe8iRVWEAJSpzMgRQs%3D5-v84cXUg%40mail.gmail.com
"I/O" seems more descriptive than "Asynchronous Behavior", given that some of
the GUCs in the section don't relate to anything asynchronous.
Most other abbreviations in the config sections are un-abbreviated, but
"Input/Output" seems less likely to be helpful than just IO or I/O.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://postgr.es/m/x3tlw2jk5gm3r3mv47hwrshffyw7halpczkfbk3peksxds7bvc@lguk43z3bsyq
Most GUCs that accept a special value to disable the feature
mention it in their GUC description. This commit adds that
information to autovacuum_vacuum_max_threshold's description.
Oversight in commit 306dc520b9.
One way autovacuum chooses tables to vacuum is by comparing the
number of updated or deleted tuples with a value calculated using
autovacuum_vacuum_threshold and autovacuum_vacuum_scale_factor.
The threshold specifies the base value for comparison, and the
scale factor specifies the fraction of the table size to add to it.
This strategy ensures that smaller tables are vacuumed after fewer
updates/deletes than larger tables, which is reasonable in many
cases but can result in infrequent vacuums on very large tables.
This is undesirable for a couple of reasons, such as very large
tables incurring a huge amount of bloat between vacuums.
This new parameter provides a way to set a limit on the value
calculated with autovacuum_vacuum_threshold and
autovacuum_vacuum_scale_factor so that very large tables are
vacuumed more frequently. By default, it is set to 100,000,000
tuples, but it can be disabled by setting it to -1. It can also be
adjusted for individual tables by changing storage parameters.
Author: Nathan Bossart <nathandbossart@gmail.com>
Co-authored-by: Frédéric Yhuel <frederic.yhuel@dalibo.com>
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: Michael Banck <mbanck@gmx.net>
Reviewed-by: Joe Conway <mail@joeconway.com>
Reviewed-by: Sami Imseih <samimseih@gmail.com>
Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Reviewed-by: wenhui qiu <qiuwenhuifx@gmail.com>
Reviewed-by: Vinícius Abrahão <vinnix.bsd@gmail.com>
Reviewed-by: Robert Treat <rob@xzilla.net>
Reviewed-by: Alena Rybakina <a.rybakina@postgrespro.ru>
Discussion: https://postgr.es/m/956435f8-3b2f-47a6-8756-8c54ded61802%40dalibo.com
logging_collector was only mentioning stderr and csvlog, and forgot
about jsonlog. Oversight in dc686681e0, that has added support for
jsonlog in log_destination.
While on it, the description in the GUC table is tweaked to be more
consistent with the documentation and postgresql.conf.sample.
Author: Umar Hayat
Reviewed-by: Ashutosh Bapat, Tom Lane
Discussion: https://postgr.es/m/CAD68Dp1K_vBYqBEukHw=1jF7e76t8aszGZTFL2ugi=H7r=a7MA@mail.gmail.com
Backpatch-through: 13
When syslogger.c was first written, we didn't want to assume that
all platforms have 64-bit ftello. But we've been assuming that
since v13 (cf commit 799d22461), so let's use that in syslogger.c
and allow log_rotation_size to range up to INT_MAX kilobytes.
The old code effectively limited log_rotation_size to 2GB regardless
of platform. While nobody's complained, that doesn't seem too far
away from what might be thought reasonable these days.
I noticed this while searching for instances of "1024L" in connection
with commit 041e8b95b. These were the last such instances.
(We still have instances of L-suffixed literals, but most of them
are associated with wait intervals for pg_usleep or similar functions.
I don't see any urgent reason to change that.)
ca9c6a5680 consolidated most of the vacuum-related GUCs' documentation
into a new subsection. af2317652d then enforced this order in
postgresql.conf.sample. This commit reorganizes the GUC groups in
guc_tables.c/h to match the updated ordering in the docs.
Reported-by: Álvaro Herrera
Reviewed-by: Álvaro Herrera, Alena Rybakina
Discussion: https://postgr.es/m/202501132046.m4mcvxxswznu%40alvherre.pgsql
This commit introduces a new parameter named
autovacuum_worker_slots that controls how many autovacuum worker
slots to reserve during server startup. Modifying this new
parameter's value does require a server restart, but it should
typically be set to the upper bound of what you might realistically
need to set autovacuum_max_workers. With that new parameter in
place, autovacuum_max_workers can now be changed with a SIGHUP
(e.g., pg_ctl reload).
If autovacuum_max_workers is set higher than
autovacuum_worker_slots, a WARNING is emitted, and the server will
only start up to autovacuum_worker_slots workers at a given time.
If autovacuum_max_workers is set to a value less than the number of
currently-running autovacuum workers, the existing workers will
continue running, but no new workers will be started until the
number of running autovacuum workers drops below
autovacuum_max_workers.
Reviewed-by: Sami Imseih, Justin Pryzby, Robert Haas, Andres Freund, Yogesh Sharma
Discussion: https://postgr.es/m/20240410212344.GA1824549%40nathanxps13
MD5 has been considered to be unsuitable for use as a cryptographic
hash algorithm for some time. Furthermore, MD5 password hashes in
PostgreSQL are vulnerable to pass-the-hash attacks, i.e., knowing
the username and hashed password is sufficient to authenticate.
The SCRAM-SHA-256 method added in v10 is not subject to these
problems and is considered to be superior to MD5.
This commit marks MD5 password support in PostgreSQL as deprecated
and to be removed in a future release. The documentation now
contains several deprecation notices, and CREATE ROLE and ALTER
ROLE now emit deprecation warnings when setting MD5 passwords. The
warnings can be disabled by setting the md5_password_warnings
parameter to "off".
Reviewed-by: Greg Sabino Mullane, Jim Nasby
Discussion: https://postgr.es/m/ZwbfpJJol7lDWajL%40nathan
The ordering of DISTINCT items is semantically insignificant, so we
can reorder them as needed. In fact, in the parser, we absorb the
sorting semantics of the sortClause as much as possible into the
distinctClause, ensuring that one clause is a prefix of the other.
This can help avoid a possible need to re-sort.
In this commit, we attempt to adjust the DISTINCT keys to match the
input path's pathkeys. This can likewise help avoid re-sorting, or
allow us to use incremental-sort to save efforts.
For DISTINCT ON expressions, the parser already ensures that they
match the initial ORDER BY expressions. When reordering the DISTINCT
keys, we must ensure that the resulting pathkey list matches the
initial distinctClause pathkeys.
This introduces a new GUC, enable_distinct_reordering, which allows
the optimization to be disabled if needed.
Author: Richard Guo
Reviewed-by: Andrei Lepikhov
Discussion: https://postgr.es/m/CAMbWs48dR26cCcX0f=8bja2JKQPcU64136kHk=xekHT9xschiQ@mail.gmail.com
The ssl_ecdh_curve GUC only accepts a single value, but the TLS
handshake can list multiple curves in the groups extension (the
extension has been renamed to contain more than elliptic curves).
This changes the GUC to accept a colon-separated list of curves.
This commit also renames the GUC to ssl_groups to match the new
nomenclature for the TLS extension.
Original patch by Erica Zhang with additional hacking by me.
Author: Erica Zhang <ericazhangy2021@qq.com>
Author: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Jacob Champion <jacob.champion@enterprisedb.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Reviewed-by: Jelte Fennema-Nio <postgres@jeltef.nl>
Discussion: https://postgr.es/m/tencent_063F89FA72CCF2E48A0DF5338841988E9809@qq.com
max_parallel_maintenance_workers has been introduced in 9da0cc3528,
and used a hardcoded limit of 1024 rather than this variable.
max_parallel_workers and max_parallel_workers_per_gather already used
MAX_PARALLEL_WORKER_LIMIT (1024) as their upper-bound since
6599c9ac33.
Author: Matthias van de Meent
Reviewed-by: Zhang Mingli
Discussion: https://postgr.es/m/CAEze2WiCiJD+8Wig_wGPyn4vgdPjbnYXy2Rw+9KYi6izTMuP=w@mail.gmail.com
This change improves the description of the
restrict_nonsystem_relation_kind parameter in guc_table.c and the
documentation for better clarity.
Backpatch to 12, where this GUC parameter was introduced.
Reviewed-by: Peter Eisentraut
Discussion: https://postgr.es/m/6a96f1af-22b4-4a80-8161-1f26606b9ee2%40eisentraut.org
Backpatch-through: 12
Report search_path changes to the client. Multi-tenant applications
often map tenants to schemas, and use search_path to pick the tenant a
given connection works with. This breaks when a connection pool (like
PgBouncer), because the search_path may change unexpectedly.
There are other GUCs we might want reported (e.g. various timeouts), but
search_path is by far the biggest foot gun that can lead either to
puzzling failures during query execution (when objects are missing or
are defined differently), or even to accessing incorrect data.
Many existing tools modify search_path, pg_dump being a notable example.
Ideally, clients could specify which GUCs are interesting and should be
subject to this reporting, but we don't support that. GUC_REPORT is what
connection pools rely on for other interesting GUCs, so just use that.
When this change was initially proposed in 2014, one of the concerns was
impact on performance. But this was addressed by commit 2432b1a040,
which ensures we report each GUC at most once per query, no matter how
many times it changed during execution.
Eventually, this might be replaced / superseded by allowing doing this
by making the protocol extensible in this direction, but it's unclear
when (or if) that happens. Until then, we can leverage GUC_REPORT.
Author: Alexander Kukushkin, Jelte Fennema-Nio
Discussion: https://postgr.es/m/CAFh8B=k8s7WrcqhafmYhdN1+E5LVzZi_QaYDq8bKvrGJTAhY2Q@mail.gmail.com
The TRACE_SORT macro guarded the availability of the trace_sort GUC
setting. But it has been enabled by default ever since it was
introduced in PostgreSQL 8.1, and there have been no reports that
someone wanted to disable it. So just remove the macro to simplify
things. (For the avoidance of doubt: The trace_sort GUC is still
there. This only removes the rarely-used macro guarding it.)
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Discussion: https://www.postgresql.org/message-id/flat/be5f7162-7c1d-44e3-9a78-74dcaa6529f2%40eisentraut.org
The code intends to allow GUCs to be set within parallel workers
via function SET clauses, but not otherwise. However, doing so fails
for "session_authorization" and "role", because the assign hooks for
those attempt to set the subsidiary "is_superuser" GUC, and that call
falls foul of the "not otherwise" prohibition. We can't switch to
using GUC_ACTION_SAVE for this, so instead add a new GUC variable
flag GUC_ALLOW_IN_PARALLEL to mark is_superuser as being safe to set
anyway. (This is okay because is_superuser has context PGC_INTERNAL
and thus only hard-wired calls can change it. We'd need more thought
before applying the flag to other GUCs; but maybe there are other
use-cases.) This isn't the prettiest fix perhaps, but other
alternatives we thought of would be much more invasive.
While here, correct a thinko in commit 059de3ca4: when rejecting
a GUC setting within a parallel worker, we should return 0 not -1
if the ereport doesn't longjmp. (This seems to have no consequences
right now because no caller cares, but it's inconsistent.) Improve
the comments to try to forestall future confusion of the same kind.
Despite the lack of field complaints, this seems worth back-patching.
Thanks to Nathan Bossart for the idea to invent a new flag,
and for review.
Discussion: https://postgr.es/m/2833457.1723229039@sss.pgh.pa.us
Since the introduction of TID store, vacuum uses far less memory in
the common case than in versions 16 and earlier. Invoking multiple
rounds of index vacuuming in turn requires a much larger table. It'd
be a good idea anyway to cover this case in regression testing, and a
lower limit is less painful for slow buildfarm animals. The reason to
do it now is to re-enable coverage of the bugfix in commit 83c39a1f7f.
For consistency, give autovacuum_work_mem the same treatment.
Suggested by Andres Freund
Tested by Melanie Plageman
Backpatch to v17, where TID store was introduced
Discussion: https://postgr.es/m/20240516205458.ohvlzis5b5tvejru@awork3.anarazel.de
Discussion: https://postgr.es/m/20240722164745.fvaoh6g6zprisqgp%40awork3.anarazel.de
When pg_dump retrieves the list of database objects and performs the
data dump, there was possibility that objects are replaced with others
of the same name, such as views, and access them. This vulnerability
could result in code execution with superuser privileges during the
pg_dump process.
This issue can arise when dumping data of sequences, foreign
tables (only 13 or later), or tables registered with a WHERE clause in
the extension configuration table.
To address this, pg_dump now utilizes the newly introduced
restrict_nonsystem_relation_kind GUC parameter to restrict the
accesses to non-system views and foreign tables during the dump
process. This new GUC parameter is added to back branches too, but
these changes do not require cluster recreation.
Back-patch to all supported branches.
Reviewed-by: Noah Misch
Security: CVE-2024-7348
Backpatch-through: 12
This converts
COPY_PARSE_PLAN_TREES
WRITE_READ_PARSE_PLAN_TREES
RAW_EXPRESSION_COVERAGE_TEST
into run-time parameters
debug_copy_parse_plan_trees
debug_write_read_parse_plan_trees
debug_raw_expression_coverage_test
They can be activated for tests using PG_TEST_INITDB_EXTRA_OPTS.
The compile-time symbols are kept for build farm compatibility, but
they now just determine the default value of the run-time settings.
Furthermore, support for these settings is not compiled in at all
unless assertions are enabled, or the new symbol
DEBUG_NODE_TESTS_ENABLED is defined at compile time, or any of the
legacy compile-time setting symbols are defined. So there is no
run-time overhead in production builds. (This is similar to the
handling of DISCARD_CACHES_ENABLED.)
Discussion: https://www.postgresql.org/message-id/flat/30747bd8-f51e-4e0c-a310-a6e2c37ec8aa%40eisentraut.org
The documentation for System V IPC parameters provides complicated
formulas to determine the appropriate values for SEMMNI and SEMMNS.
Furthermore, these formulas have often been wrong because folks
forget to update them (e.g., when adding a new auxiliary process).
This commit introduces a new runtime-computed GUC named
num_os_semaphores that reports the number of semaphores needed for
the configured number of allowed connections, worker processes,
etc. This new GUC allows us to simplify the formulas in the
documentation, and it should help prevent future inaccuracies.
Like the other runtime-computed GUCs, users can view it with
"postgres -C" before starting the server, which is useful for
preconfiguring the necessary operating system resources.
Reviewed-by: Tom Lane, Sami Imseih, Andres Freund, Robert Haas
Discussion: https://postgr.es/m/20240517164452.GA1914161%40nathanxps13
Add extern declarations in appropriate header files for global
variables related to GUC. In many cases, this was handled quite
inconsistently before, with some GUC variables declared in a header
file and some only pulled in via ad-hoc extern declarations in various
.c files.
Also add PGDLLIMPORT qualifications to those variables. These were
previously missing because src/tools/mark_pgdllimport.pl has only been
used with header files.
This also fixes -Wmissing-variable-declarations warnings for GUC
variables (not yet part of the standard warning options).
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/e0a62134-83da-4ba4-8cdb-ceb0111c95ce@eisentraut.org
Each of max_connections, max_worker_processes,
autovacuum_max_workers, and max_wal_senders has a GUC check hook
that verifies the sum of those GUCs does not exceed a hard-coded
limit (see the comment for MAX_BACKENDS in postmaster.h). In
general, the hooks effectively guard against egregious
misconfigurations.
However, this approach has some problems. Since these check hooks
are called as each GUC is assigned its user-specified value, only
one of the hooks will be called with all the relevant GUCs set. If
one or more of the user-specified values are less than the initial
values of the GUCs' underlying variables, false positives can
occur.
Furthermore, the error message emitted when one of the check hooks
fails is not tremendously helpful. For example, the command
$ pg_ctl -D . start -o "-c max_connections=262100 -c max_wal_senders=10000"
fails with the following error:
FATAL: invalid value for parameter "max_wal_senders": 10000
Fortunately, there is an extra copy of this check in
InitializeMaxBackends() that we can rely on, so this commit removes
the aforementioned GUC check hooks in favor of that one. It also
enhances the error message to clearly show the values of the
relevant GUCs and the hard-coded limit their sum may not exceed.
The downside of this change is that server startup progresses
further before failing due to such misconfigurations (thus taking
longer), but these failures are expected to be rare, so we don't
anticipate any real harm in practice.
Reviewed-by: Tom Lane
Discussion: https://postgr.es/m/ZnMr2k-Nk5vj7T7H%40nathan
src/backend/libpq/pqcomm.c: "postmaster/postmaster.h" for Unix_socket_group, Unix_socket_permissions
src/backend/utils/init/globals.c: "postmaster/postmaster.h" for MyClientSocket
src/backend/utils/misc/guc_tables.c: "utils/rls.h" for row_security
src/backend/utils/sort/tuplesort.c: "utils/guc.h" for trace_sort
Nothing currently diagnoses missing includes for global variables, but
this is being cleaned up, and these ones had an obvious header file
available.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/e0a62134-83da-4ba4-8cdb-ceb0111c95ce@eisentraut.org
The standby_slot_names GUC allows the specification of physical standby
slots that must be synchronized before the logical walsenders associated
with logical failover slots. However, for this purpose, the GUC name is
too generic.
Author: Hou Zhijie
Reviewed-by: Bertrand Drouvot, Masahiko Sawada
Backpatch-through: 17
Discussion: https://postgr.es/m/ZnWeUgdHong93fQN@momjian.us
After further review, we want to move in the direction of always
quoting GUC names in error messages, rather than the previous (PG16)
wildly mixed practice or the intermittent (mid-PG17) idea of doing
this depending on how possibly confusing the GUC name is.
This commit applies appropriate quotes to (almost?) all mentions of
GUC names in error messages. It partially supersedes a243569bf6 and
8d9978a717, which had moved things a bit in the opposite direction
but which then were abandoned in a partial state.
Author: Peter Smith <smithpb2250@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/CAHut%2BPv-kSN8SkxSdoHano_wPubqcg5789ejhCDZAcLFceBR-w%40mail.gmail.com
The new "log_connection_negotiation" server option causes the server
to print messages to the log when it receives a SSLRequest or
GSSENCRequest packet from the client. Together with "log_connections",
it gives a trace of how a connection and encryption is
negotiatated. Use the option in the libpq_encryption test, to verify
in more detail how libpq negotiates encryption with different
gssencmode and sslmode options.
This revealed a couple of cases where libpq retries encryption or
authentication, when it should already know that it cannot succeed. I
marked them with XXX comments in the test tables. They only happen
when the connection was going to fail anyway, and only with rare
combinations of options, so they're not serious.
Discussion: https://www.postgresql.org/message-id/CAEze2Wja8VUoZygCepwUeiCrWa4jP316k0mvJrOW4PFmWP0Tcw@mail.gmail.com
Replace (expr op C1) OR (expr op C2) ... with expr op ANY(ARRAY[C1, C2, ...])
on the preliminary stage of optimization when we are still working with the
expression tree.
Here Cn is a n-th constant expression, 'expr' is non-constant expression, 'op'
is an operator which returns boolean result and has a commuter (for the case
of reverse order of constant and non-constant parts of the expression,
like 'Cn op expr').
Sometimes it can lead to not optimal plan. This is why there is a
or_to_any_transform_limit GUC. It specifies a threshold value of length of
arguments in an OR expression that triggers the OR-to-ANY transformation.
Generally, more groupable OR arguments mean that transformation will be more
likely to win than to lose.
Discussion: https://postgr.es/m/567ED6CA.2040504%40sigaev.ru
Author: Alena Rybakina <lena.ribackina@yandex.ru>
Author: Andrey Lepikhov <a.lepikhov@postgrespro.ru>
Reviewed-by: Peter Geoghegan <pg@bowt.ie>
Reviewed-by: Ranier Vilela <ranier.vf@gmail.com>
Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Jian He <jian.universality@gmail.com>
The BAS_VACUUM ring size has been 256kB since commit d526575f introduced
the mechanism 17 years ago. Commit 1cbbee03 recently made it
configurable but retained the traditional default. The correct default
size has been debated for years, but 256kB is certainly very small.
VACUUM soon needs to write back data it dirtied only 32 blocks ago,
which usually requires flushing the WAL. New experiments in prefetching
pages for VACUUM exacerbated the problem by crashing into dirty data
even sooner. Let's make the default 2MB. That's 1.6% of the default
toy buffer pool size, and 0.2% of 1GB, which would be a considered a
small shared_buffers setting for a real system these days. Users are
still free to set the GUC to a different value.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20240403221257.md4gfki3z75cdyf6%40awork3.anarazel.de
Discussion: https://postgr.es/m/CA%2BhUKGLY4Q4ZY4f1rvnFtv6%2BPkjNf8MejdPkcju3Qii9DYqqcQ%40mail.gmail.com
Break ReadBuffer() up into two steps. StartReadBuffers() and
WaitReadBuffers() give us two main advantages:
1. Multiple consecutive blocks can be read with one system call.
2. Advice (hints of future reads) can optionally be issued to the
kernel ahead of time.
The traditional ReadBuffer() function is now implemented in terms of
those functions, to avoid duplication.
A new GUC io_combine_limit is defined, and the functions for limiting
per-backend pin counts are made into public APIs. Those are provided
for use by callers of StartReadBuffers(), when deciding how many buffers
to read at once. The following commit will add a higher level mechanism
for doing that automatically with a practical interface.
With some more infrastructure in later work, StartReadBuffers() could
be extended to start real asynchronous I/O instead of just issuing
advice and leaving WaitReadBuffers() to do the work synchronously.
Author: Thomas Munro <thomas.munro@gmail.com>
Author: Andres Freund <andres@anarazel.de> (some optimization tweaks)
Reviewed-by: Melanie Plageman <melanieplageman@gmail.com>
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Nazir Bilal Yavuz <byavuz81@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Tested-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Discussion: https://postgr.es/m/CA+hUKGJkOiOCa+mag4BF+zHo7qo=o9CFheB8=g6uT5TUm2gkvA@mail.gmail.com
This is marked PGC_SIGHUP, so it can only be set in a configuration
file, not anywhere else; and it is also marked GUC_DISALLOW_IN_AUTO_FILE,
so it can't be set using ALTER SYSTEM. When set to false, the
ALTER SYSTEM command is disallowed.
There was considerable concern that this would be misinterpreted as
a security feature, which it is not, because a determined superuser
has various ways of bypassing it. Hence, a lot of work has gone into
wordsmithing the documentation, in the hopes of avoiding any such
confusion.
Jelte Fennemia-Nio and Gabriele Bartolini, with wording suggestions
for the documentation from many others.
Discussion: http://postgr.es/m/CA%2BVUV5rEKt2%2BCdC_KUaPoihMu%2Bi5ChT4WVNTr4CD5-xXZUfuQw%40mail.gmail.com
The user-facing name is "Other Platforms and Clients", but the
internal name seems too focused on clients specifically, especially
given the plan to add a new setting to this session that is about
platform or deployment model compatibility rather than client
compatibility.
Jelte Fennema-Nio
Discussion: http://postgr.es/m/CAGECzQTfMbDiM6W3av+3weSnHxJvPmuTEcjxVvSt91sQBdOxuQ@mail.gmail.com
This commit limits the maximum value of wal_summary_keep_time to
INT_MAX / SECS_PER_MINUTE to avoid overflow when it is converted to
seconds. In passing, use the HOURS_PER_DAY, MINS_PER_HOUR, and
SECS_PER_MINUTE macros in the code for this GUC instead of hard-
coding those values.
Discussion: https://postgr.es/m/20240314210010.GA3056455%40nathanxps13
