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
This patch provides a way to ensure that physical standbys that are
potential failover candidates have received and flushed changes before
the primary server making them visible to subscribers. Doing so guarantees
that the promoted standby server is not lagging behind the subscribers
when a failover is necessary.
The logical walsender now guarantees that all local changes are sent and
flushed to the standby servers corresponding to the replication slots
specified in 'standby_slot_names' before sending those changes to the
subscriber.
Additionally, the SQL functions pg_logical_slot_get_changes,
pg_logical_slot_peek_changes and pg_replication_slot_advance are modified
to ensure that they process changes for failover slots only after physical
slots specified in 'standby_slot_names' have confirmed WAL receipt for those.
Author: Hou Zhijie and Shveta Malik
Reviewed-by: Masahiko Sawada, Peter Smith, Bertrand Drouvot, Ajin Cherian, Nisha Moond, Amit Kapila
Discussion: https://postgr.es/m/514f6f2f-6833-4539-39f1-96cd1e011f23@enterprisedb.com
as determined by include-what-you-use (IWYU)
While IWYU also suggests to *add* a bunch of #include's (which is its
main purpose), this patch does not do that. In some cases, a more
specific #include replaces another less specific one.
Some manual adjustments of the automatic result:
- IWYU currently doesn't know about includes that provide global
variable declarations (like -Wmissing-variable-declarations), so
those includes are being kept manually.
- All includes for port(ability) headers are being kept for now, to
play it safe.
- No changes of catalog/pg_foo.h to catalog/pg_foo_d.h, to keep the
patch from exploding in size.
Note that this patch touches just *.c files, so nothing declared in
header files changes in hidden ways.
As a small example, in src/backend/access/transam/rmgr.c, some IWYU
pragma annotations are added to handle a special case there.
Discussion: https://www.postgresql.org/message-id/flat/af837490-6b2f-46df-ba05-37ea6a6653fc%40eisentraut.org
More precisely, what we do here is make the SLRU cache sizes
configurable with new GUCs, so that sites with high concurrency and big
ranges of transactions in flight (resp. multixacts/subtransactions) can
benefit from bigger caches. In order for this to work with good
performance, two additional changes are made:
1. the cache is divided in "banks" (to borrow terminology from CPU
caches), and algorithms such as eviction buffer search only affect
one specific bank. This forestalls the problem that linear searching
for a specific buffer across the whole cache takes too long: we only
have to search the specific bank, whose size is small. This work is
authored by Andrey Borodin.
2. Change the locking regime for the SLRU banks, so that each bank uses
a separate LWLock. This allows for increased scalability. This work
is authored by Dilip Kumar. (A part of this was previously committed as
d172b717c6f4.)
Special care is taken so that the algorithms that can potentially
traverse more than one bank release one bank's lock before acquiring the
next. This should happen rarely, but particularly clog.c's group commit
feature needed code adjustment to cope with this. I (Álvaro) also added
lots of comments to make sure the design is sound.
The new GUCs match the names introduced by bcdfa5f2e2 in the
pg_stat_slru view.
The default values for these parameters are similar to the previous
sizes of each SLRU. commit_ts, clog and subtrans accept value 0, which
means to adjust by dividing shared_buffers by 512 (so 2MB for every 1GB
of shared_buffers), with a cap of 8MB. (A new slru.c function
SimpleLruAutotuneBuffers() was added to support this.) The cap was
previously 1MB for clog, so for sites with more than 512MB of shared
memory the total memory used increases, which is likely a good tradeoff.
However, other SLRUs (notably multixact ones) retain smaller sizes and
don't support a configured value of 0. These values based on
shared_buffers may need to be revisited, but that's an easy change.
There was some resistance to adding these new GUCs: it would be better
to adjust to memory pressure automatically somehow, for example by
stealing memory from shared_buffers (where the caches can grow and
shrink naturally). However, doing that seems to be a much larger
project and one which has made virtually no progress in several years,
and because this is such a pain point for so many users, here we take
the pragmatic approach.
Author: Andrey Borodin <x4mmm@yandex-team.ru>
Author: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Amul Sul, Gilles Darold, Anastasia Lubennikova,
Ivan Lazarev, Robert Haas, Thomas Munro, Tomas Vondra,
Yura Sokolov, Васильев Дмитрий (Dmitry Vasiliev).
Discussion: https://postgr.es/m/2BEC2B3F-9B61-4C1D-9FB5-5FAB0F05EF86@yandex-team.ru
Discussion: https://postgr.es/m/CAFiTN-vzDvNz=ExGXz6gdyjtzGixKSqs0mKHMmaQ8sOSEFZ33A@mail.gmail.com
This is in the same spirit as ef5e2e9085, updating this time some
arrays in parser.c, relpath.c, guc_tables.c and pg_dump_sort.c so as the
order of their elements has no need to match the enum structures they
are based on anymore.
Author: Jelte Fennema-Nio
Reviewed-by: Jian He, Japin Li
Discussion: https://postgr.es/m/CAGECzQT3caUbcCcszNewCCmMbCuyP7XNAm60J3ybd6PN5kH2Dw@mail.gmail.com
By enabling slot synchronization, all the failover logical replication
slots on the primary (assuming configurations are appropriate) are
automatically created on the physical standbys and are synced
periodically. The slot sync worker on the standby server pings the primary
server at regular intervals to get the necessary failover logical slots
information and create/update the slots locally. The slots that no longer
require synchronization are automatically dropped by the worker.
The nap time of the worker is tuned according to the activity on the
primary. The slot sync worker waits for some time before the next
synchronization, with the duration varying based on whether any slots were
updated during the last cycle.
A new parameter sync_replication_slots enables or disables this new
process.
On promotion, the slot sync worker is shut down by the startup process to
drop any temporary slots acquired by the slot sync worker and to prevent
the worker from trying to fetch the failover slots.
A functionality to allow logical walsenders to wait for the physical will
be done in a subsequent commit.
Author: Shveta Malik, Hou Zhijie based on design inputs by Masahiko Sawada and Amit Kapila
Reviewed-by: Masahiko Sawada, Bertrand Drouvot, Peter Smith, Dilip Kumar, Ajin Cherian, Nisha Moond, Kuroda Hayato, Amit Kapila
Discussion: https://postgr.es/m/514f6f2f-6833-4539-39f1-96cd1e011f23@enterprisedb.com
This commit adds timeout that is expected to be used as a prevention
of long-running queries. Any session within the transaction will be
terminated after spanning longer than this timeout.
However, this timeout is not applied to prepared transactions.
Only transactions with user connections are affected.
Discussion: https://postgr.es/m/CAAhFRxiQsRs2Eq5kCo9nXE3HTugsAAJdSQSmxncivebAxdmBjQ%40mail.gmail.com
Author: Andrey Borodin <amborodin@acm.org>
Author: Japin Li <japinli@hotmail.com>
Author: Junwang Zhao <zhjwpku@gmail.com>
Reviewed-by: Nikolay Samokhvalov <samokhvalov@gmail.com>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: bt23nguyent <bt23nguyent@oss.nttdata.com>
Reviewed-by: Yuhang Qiu <iamqyh@gmail.com>
When evaluating a query with a multi-column GROUP BY clause, we can minimize
sort operations or avoid them if we synchronize the order of GROUP BY clauses
with the ORDER BY sort clause or sort order, which comes from the underlying
query tree. Grouping does not imply any ordering, so we can compare
the keys in arbitrary order, and a Hash Agg leverages this. But for Group Agg,
we simply compared keys in the order specified in the query. This commit
explores alternative ordering of the keys, trying to find a cheaper one.
The ordering of group keys may interact with other parts of the query, some of
which may not be known while planning the grouping. For example, there may be
an explicit ORDER BY clause or some other ordering-dependent operation higher up
in the query, and using the same ordering may allow using either incremental
sort or even eliminating the sort entirely.
The patch always keeps the ordering specified in the query, assuming the user
might have additional insights.
This introduces a new GUC enable_group_by_reordering so that the optimization
may be disabled if needed.
Discussion: https://postgr.es/m/7c79e6a5-8597-74e8-0671-1c39d124c9d6%40sigaev.ru
Author: Andrei Lepikhov, Teodor Sigaev
Reviewed-by: Tomas Vondra, Claudio Freire, Gavin Flower, Dmitry Dolgov
Reviewed-by: Robert Haas, Pavel Borisov, David Rowley, Zhihong Yu
Reviewed-by: Tom Lane, Alexander Korotkov, Richard Guo, Alena Rybakina
When enabled (default off), this logs a backtrace anytime elog() or an
equivalent ereport() for internal errors is called.
This is not well covered by the existing backtrace_functions, because
there are many equally-worded low-level errors in many functions. And
if you find out where the error is, then you need to manually rewrite
the elog() to ereport() to attach the errbacktrace(), which is
annoying. Having a backtrace automatically on every elog() call could
be very helpful during development for various kinds of common errors
from palloc, syscache, node support, etc.
Discussion: https://www.postgresql.org/message-id/flat/ba76c6bc-f03f-4285-bf16-47759cfcab9e@eisentraut.org
When active, this process writes WAL summary files to
$PGDATA/pg_wal/summaries. Each summary file contains information for a
certain range of LSNs on a certain TLI. For each relation, it stores a
"limit block" which is 0 if a relation is created or destroyed within
a certain range of WAL records, or otherwise the shortest length to
which the relation was truncated during that range of WAL records, or
otherwise InvalidBlockNumber. In addition, it stores a list of blocks
which have been modified during that range of WAL records, but
excluding blocks which were removed by truncation after they were
modified and never subsequently modified again.
In other words, it tells us which blocks need to copied in case of an
incremental backup covering that range of WAL records. But this
doesn't yet add the capability to actually perform an incremental
backup; the next patch will do that.
A new parameter summarize_wal enables or disables this new background
process. The background process also automatically deletes summary
files that are older than wal_summarize_keep_time, if that parameter
has a non-zero value and the summarizer is configured to run.
Patch by me, with some design help from Dilip Kumar and Andres Freund.
Reviewed by Matthias van de Meent, Dilip Kumar, Jakub Wartak, Peter
Eisentraut, and Álvaro Herrera.
Discussion: http://postgr.es/m/CA+TgmoYOYZfMCyOXFyC-P+-mdrZqm5pP2N7S-r0z3_402h9rsA@mail.gmail.com
This GUC was intended as a debugging help in the 9.0 area when hot
standby and streaming replication were being developped, able to offer
more information at LOG level rather than DEBUGn. There are more tools
available these days that are able to offer rather equivalent
information, like pg_waldump introduced in 9.3. It is not obvious how
this facility is useful these days, so let's remove it.
Author: Bharath Rupireddy
Discussion: https://postgr.es/m/ZXEXEAUVFrvpquSd@paquier.xyz
Quotes are applied to GUCs in a very inconsistent way across the code
base, with a mix of double quotes or no quotes used. This commit
removes double quotes around all the GUC names that are obviously
referred to as parameters with non-English words (use of underscore,
mixed case, etc).
This is the result of a discussion with Álvaro Herrera, Nathan Bossart,
Laurenz Albe, Peter Eisentraut, Tom Lane and Daniel Gustafsson.
Author: Peter Smith
Discussion: https://postgr.es/m/CAHut+Pv-kSN8SkxSdoHano_wPubqcg5789ejhCDZAcLFceBR-w@mail.gmail.com
This avoids the wraparound in async.c and removes the corresponding code
complexity. The maximum amount of allocated SLRU pages for NOTIFY / LISTEN
queue is now determined by the max_notify_queue_pages GUC. The default
value is 1048576. It allows to consume up to 8 GB of disk space which is
exactly the limit we had previously.
Author: Maxim Orlov, Aleksander Alekseev, Alexander Korotkov, Teodor Sigaev
Author: Nikita Glukhov, Pavel Borisov, Yura Sokolov
Reviewed-by: Jacob Champion, Heikki Linnakangas, Alexander Korotkov
Reviewed-by: Japin Li, Pavel Borisov, Tom Lane, Peter Eisentraut, Andres Freund
Reviewed-by: Andrey Borodin, Dilip Kumar, Aleksander Alekseev
Discussion: https://postgr.es/m/CACG%3DezZe1NQSCnfHOr78AtAZxJZeCvxrts0ygrxYwe%3DpyyjVWA%40mail.gmail.com
Discussion: https://postgr.es/m/CAJ7c6TPDOYBYrnCAeyndkBktO0WG2xSdYduTF0nxq%2BvfkmTF5Q%40mail.gmail.com
We don't want existing slots in the old cluster to get invalidated during
the upgrade. During an upgrade, we set this variable to -1 via the command
line in an attempt to prevent such invalidations, but users have ways to
override it. This patch ensures the value is not overridden by the user.
Author: Kyotaro Horiguchi
Reviewed-by: Peter Smith, Alvaro Herrera
Discussion: http://postgr.es/m/20231027.115759.2206827438943188717.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 is proved that the join can be replaced with
a scan without impacting the query result. Self join and inner relation are
replaced with the outer in query, equivalence classes, and planner info
structures. Also, inner restrictlist moves to the outer one with removing
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 === selectivity estimations, and potentially
can improve total planner prediction for the query.
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 row as the outer one.
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 inner and outer clauses must have
an exact match.
The relation replacement procedure is not trivial and it is partly combined
with the one, used to remove useless left joins. Tests, covering this feature,
were added to join.sql. Some 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, Alexander Kuzmenkov
Reviewed-by: Tom Lane, Robert Haas, Andres Freund, Simon Riggs, Jonathan S. Katz
Reviewed-by: David Rowley, Thomas Munro, Konstantin Knizhnik, Heikki Linnakangas
Reviewed-by: Hywel Carver, Laurenz Albe, Ronan Dunklau, vignesh C, Zhihong Yu
Reviewed-by: Greg Stark, Jaime Casanova, Michał Kłeczek, Alena Rybakina
Reviewed-by: Alexander Korotkov
* sync_method is renamed to wal_sync_method.
* sync_method_options[] is renamed to wal_sync_method_options[].
* assign_xlog_sync_method() is renamed to assign_wal_sync_method().
* The names of the available synchronization methods are now
prefixed with "WAL_SYNC_METHOD_" and have been moved into a
WalSyncMethod enum.
* PLATFORM_DEFAULT_SYNC_METHOD is renamed to
PLATFORM_DEFAULT_WAL_SYNC_METHOD, and DEFAULT_SYNC_METHOD is
renamed to DEFAULT_WAL_SYNC_METHOD.
These more descriptive names help distinguish the code for
wal_sync_method from the code for DataDirSyncMethod (e.g., the
recovery_init_sync_method configuration parameter and the
--sync-method option provided by several frontend utilities). This
change also prevents name collisions between the aforementioned
sets of code. Since this only improves the naming of internal
identifiers, there should be no behavior change.
Author: Maxim Orlov
Discussion: https://postgr.es/m/CACG%3DezbL1gwE7_K7sr9uqaCGkWhmvRTcTEnm3%2BX1xsRNwbXULQ%40mail.gmail.com
In order to troubleshoot misbehaving or buggy event triggers, the
documented advice is to enter single-user mode. In an attempt to
reduce the number of situations where single-user mode is required
(or even recommended) for non-extraordinary maintenance, this GUC
allows to temporarily suspend event triggers.
This was originally extracted from a larger patchset which aimed
at supporting event triggers on login events.
Reviewed-by: Ted Yu <yuzhihong@gmail.com>
Reviewed-by: Mikhail Gribkov <youzhick@gmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/9140106E-F9BF-4D85-8FC8-F2D3C094A6D9@yesql.se
Discussion: https://postgr.es/m/0d46d29f-4558-3af9-9c85-7774e14a7709@postgrespro.ru
This commit renames RecoveryInitSyncMethod to DataDirSyncMethod and
moves it to common/file_utils.h. This is preparatory work for a
follow-up commit that will allow specifying the synchronization
method in frontend utilities such as pg_upgrade and pg_basebackup.
Reviewed-by: Michael Paquier
Discussion: https://postgr.es/m/ZN2ZB4afQ2JbR9TA%40paquier.xyz
The logical_replication_mode GUC is intended for testing and debugging
purposes, but its current name may be misleading and encourage users to make
unnecessary changes.
To avoid confusion, renaming the GUC to a less misleading name
debug_logical_replication_streaming that casual users are less likely to mistakenly
assume needs to be modified in a regular logical replication setup.
Author: Hou Zhijie <houzj.fnst@cn.fujitsu.com>
Reviewed-by: Peter Smith <smithpb2250@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/d672d774-c44b-6fec-f993-793e744f169a%40eisentraut.org
Make the primary messages more compact and make the detail messages
uniform. In initdb.c and pg_resetwal.c, use the newish
option_parse_int() to simplify some of the option parsing. For the
backend GUC wal_segment_size, add a GUC check hook to do the
verification instead of coding it in bootstrap.c. This might be
overkill, but that way the check is in the right place and it becomes
more self-documenting.
In passing, make pg_controldata use the logging API for warning
messages.
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Discussion: https://www.postgresql.org/message-id/flat/9939aa8a-d7be-da2c-7715-0a0b5535a1f7@eisentraut.org
Peter Eisentraut