This is useful for extensions to get snapshot and shmem data for custom
cumulative statistics when these have a fixed number of objects, so as
these do not need to know about the snapshot internals, aka pgStatLocal.
An upcoming commit introducing an example template for custom cumulative
stats with fixed-numbered objects will make use of these. I have
noticed that this is useful for extension developers while hacking my
own example, actually.
Author: Michael Paquier
Reviewed-by: Dmitry Dolgov, Bertrand Drouvot
Discussion: https://postgr.es/m/Zmqm9j5EO0I4W8dx@paquier.xyz
This commit adds support in the backend for $subject, allowing
out-of-core extensions to plug their own custom kinds of cumulative
statistics. This feature has come up a few times into the lists, and
the first, original, suggestion came from Andres Freund, about
pg_stat_statements to use the cumulative statistics APIs in shared
memory rather than its own less efficient internals. The advantage of
this implementation is that this can be extended to any kind of
statistics.
The stats kinds are divided into two parts:
- The in-core "builtin" stats kinds, with designated initializers, able
to use IDs up to 128.
- The "custom" stats kinds, able to use a range of IDs from 128 to 256
(128 slots available as of this patch), with information saved in
TopMemoryContext. This can be made larger, if necessary.
There are two types of cumulative statistics in the backend:
- For fixed-numbered objects (like WAL, archiver, etc.). These are
attached to the snapshot and pgstats shmem control structures for
efficiency, and built-in stats kinds still do that to avoid any
redirection penalty. The data of custom kinds is stored in a first
array in snapshot structure and a second array in the shmem control
structure, both indexed by their ID, acting as an equivalent of the
builtin stats.
- For variable-numbered objects (like tables, functions, etc.). These
are stored in a dshash using the stats kind ID in the hash lookup key.
Internally, the handling of the builtin stats is unchanged, and both
fixed and variabled-numbered objects are supported. Structure
definitions for builtin stats kinds are renamed to reflect better the
differences with custom kinds.
Like custom RMGRs, custom cumulative statistics can only be loaded with
shared_preload_libraries at startup, and must allocate a unique ID
shared across all the PostgreSQL extension ecosystem with the following
wiki page to avoid conflicts:
https://wiki.postgresql.org/wiki/CustomCumulativeStats
This makes the detection of the stats kinds and their handling when
reading and writing stats much easier than, say, allocating IDs for
stats kinds from a shared memory counter, that may change the ID used by
a stats kind across restarts. When under development, extensions can
use PGSTAT_KIND_EXPERIMENTAL.
Two examples that can be used as templates for fixed-numbered and
variable-numbered stats kinds will be added in some follow-up commits,
with tests to provide coverage.
Some documentation is added to explain how to use this plugin facility.
Author: Michael Paquier
Reviewed-by: Dmitry Dolgov, Bertrand Drouvot
Discussion: https://postgr.es/m/Zmqm9j5EO0I4W8dx@paquier.xyz
pg_wal_replay_wait() is to be used on standby and specifies waiting for
the specific WAL location to be replayed. This option is useful when
the user makes some data changes on primary and needs a guarantee to see
these changes are on standby.
The queue of waiters is stored in the shared memory as an LSN-ordered pairing
heap, where the waiter with the nearest LSN stays on the top. During
the replay of WAL, waiters whose LSNs have already been replayed are deleted
from the shared memory pairing heap and woken up by setting their latches.
pg_wal_replay_wait() needs to wait without any snapshot held. Otherwise,
the snapshot could prevent the replay of WAL records, implying a kind of
self-deadlock. This is why it is only possible to implement
pg_wal_replay_wait() as a procedure working without an active snapshot,
not a function.
Catversion is bumped.
Discussion: https://postgr.es/m/eb12f9b03851bb2583adab5df9579b4b%40postgrespro.ru
Author: Kartyshov Ivan, Alexander Korotkov
Reviewed-by: Michael Paquier, Peter Eisentraut, Dilip Kumar, Amit Kapila
Reviewed-by: Alexander Lakhin, Bharath Rupireddy, Euler Taveira
Reviewed-by: Heikki Linnakangas, Kyotaro Horiguchi
A follow-up patch is planned to make cumulative statistics pluggable,
and using a type is useful in the internal routines used by pgstats as
PgStat_Kind may have a value that was not originally in the enum removed
here, once made pluggable.
While on it, this commit switches pgstat_is_kind_valid() to use
PgStat_Kind rather than an int, to be more consistent with its existing
callers. Some loops based on the stats kind IDs are switched to use
PgStat_Kind rather than int, for consistency with the new time.
Author: Michael Paquier
Reviewed-by: Dmitry Dolgov, Bertrand Drouvot
Discussion: https://postgr.es/m/Zmqm9j5EO0I4W8dx@paquier.xyz
This is used in the startup process to check that the pgstats file we
are reading includes the redo LSN referring to the shutdown checkpoint
where it has been written. The redo LSN in the pgstats file needs to
match with what the control file has.
This is intended to be used for an upcoming change that will extend the
write of the stats file to happen during checkpoints, rather than only
shutdown sequences.
Bump PGSTAT_FILE_FORMAT_ID.
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/Zp8o6_cl0KSgsnvS@paquier.xyz
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
Until now we generated an ExprState for each parameter to a SubPlan and
evaluated them one-by-one ExecScanSubPlan. That's sub-optimal as creating lots
of small ExprStates
a) makes JIT compilation more expensive
b) wastes memory
c) is a bit slower to execute
This commit arranges to evaluate parameters to a SubPlan as part of the
ExprState referencing a SubPlan, using the new EEOP_PARAM_SET expression
step. We emit one EEOP_PARAM_SET for each argument to a subplan, just before
the EEOP_SUBPLAN step.
It likely is worth using EEOP_PARAM_SET in other places as well, e.g. for
SubPlan outputs, nestloop parameters and - more ambitiously - to get rid of
ExprContext->domainValue/caseValue/ecxt_agg*. But that's for later.
Author: Andres Freund <andres@anarazel.de>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Alena Rybakina <lena.ribackina@yandex.ru>
Discussion: https://postgr.es/m/20230225214401.346ancgjqc3zmvek@awork3.anarazel.de
RefreshMatviewByOid is used for both REFRESH and CREATE MATERIALIZED
VIEW. This flag is currently just used for handling internal error
messages, but also aimed to improve code-readability.
Author: Yugo Nagata
Discussion: https://postgr.es/m/20240726122630.70e889f63a4d7e26f8549de8@sraoss.co.jp
This new function returns the data for the given sequence, i.e.,
the values within the sequence tuple. Since this function is a
substitute for SELECT from the sequence, the SELECT privilege is
required on the sequence in question. It returns all NULLs for
sequences for which we lack privileges, other sessions' temporary
sequences, and unlogged sequences on standbys.
This function is primarily intended for use by pg_dump in a
follow-up commit that will use it to optimize dumpSequenceData().
Like pg_sequence_last_value(), which is a support function for the
pg_sequences system view, pg_sequence_read_tuple() is left
undocumented.
Bumps catversion.
Reviewed-by: Michael Paquier, Tom Lane
Discussion: https://postgr.es/m/20240503025140.GA1227404%40nathanxps13
Commit 9d9b9d46f3 removed the function (or rather, moved it to a
different source file and renamed it to SendCancelRequest), but forgot
the declaration in the header file.
Previously we had a fallback implementation that made a harmless system
call, based on the assumption that system calls must contain a memory
barrier. That shouldn't be reached on any current system, and it seems
highly likely that we can easily find out how to request explicit memory
barriers, if we've already had to find out how to do atomics on a
hypothetical new system.
Removed comments and a function name referred to a spinlock used for
fallback memory barriers, but that changed in 1b468a13, which left some
misleading words behind in a few places.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Suggested-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/721bf39a-ed8a-44b0-8b8e-be3bd81db748%40technowledgy.de
Discussion: https://postgr.es/m/3351991.1697728588%40sss.pgh.pa.us
Previously we had a fallback implementation of pg_compiler_barrier()
that called an empty function across a translation unit boundary so the
compiler couldn't see what it did. That shouldn't be needed on any
current systems, and might not even work with a link time optimizer.
Since we now require compiler-specific knowledge of how to implement
atomics, we should also know how to implement compiler barriers on a
hypothetical new system.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Suggested-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/721bf39a-ed8a-44b0-8b8e-be3bd81db748%40technowledgy.de
Discussion: https://postgr.es/m/3351991.1697728588%40sss.pgh.pa.us
Modern versions of all relevant architectures and tool chains have
atomics support. Since edadeb07, there is no remaining reason to carry
code that simulates atomic flags and uint32 imperfectly with spinlocks.
64 bit atomics are still emulated with spinlocks, if needed, for now.
Any modern compiler capable of implementing C11 <stdatomic.h> must have
the underlying operations we need, though we don't require C11 yet. We
detect certain compilers and architectures, so hypothetical new systems
might need adjustments here.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (concept, not the patch)
Reviewed-by: Andres Freund <andres@anarazel.de> (concept, not the patch)
Discussion: https://postgr.es/m/3351991.1697728588%40sss.pgh.pa.us
Now that the result of pg_newlocale_from_collation() is always
non-NULL, then we can move the collate_is_c and ctype_is_c flags into
pg_locale_t. That simplifies the logic in lc_collate_is_c() and
lc_ctype_is_c(), removing the dependence on setlocale().
This commit also eliminates the multi-stage initialization of the
collation cache.
As long as we have catalog access, then it's now safe to call
pg_newlocale_from_collation() without checking lc_collate_is_c()
first.
Discussion: https://postgr.es/m/cfd9eb85-c52a-4ec9-a90e-a5e4de56e57d@eisentraut.org
Reviewed-by: Peter Eisentraut, Andreas Karlsson
To determine if the two relations being joined can use partitionwise
join, we need to verify the existence of equi-join conditions
involving pairs of matching partition keys for all partition keys.
Currently we do that by looking through the join's restriction
clauses. However, it has been discovered that this approach is
insufficient, because there might be partition keys known equal by a
specific EC, but they do not form a join clause because it happens
that other members of the EC than the partition keys are constrained
to become a join clause.
To address this issue, in addition to examining the join's restriction
clauses, we also check if any partition keys are known equal by ECs,
by leveraging function exprs_known_equal(). To accomplish this, we
enhance exprs_known_equal() to check equality per the semantics of the
opfamily, if provided.
It could be argued that exprs_known_equal() could be called O(N^2)
times, where N is the number of partition key expressions, resulting
in noticeable performance costs if there are a lot of partition key
expressions. But I think this is not a problem. The number of a
joinrel's partition key expressions would only be equal to the join
degree, since each base relation within the join contributes only one
partition key expression. That is to say, it does not scale with the
number of partitions. A benchmark with a query involving 5-way joins
of partitioned tables, each with 3 partition keys and 1000 partitions,
shows that the planning time is not significantly affected by this
patch (within the margin of error), particularly when compared to the
impact caused by partitionwise join.
Thanks to Tom Lane for the idea of leveraging exprs_known_equal() to
check if partition keys are known equal by ECs.
Author: Richard Guo, Tom Lane
Reviewed-by: Tom Lane, Ashutosh Bapat, Robert Haas
Discussion: https://postgr.es/m/CAN_9JTzo_2F5dKLqXVtDX5V6dwqB0Xk+ihstpKEt3a1LT6X78A@mail.gmail.com
The current method of coercing the boolean result value of
JsonPathExists() to the target type specified for an EXISTS column,
which is to call the type's input function via json_populate_type(),
leads to an error when the target type is integer, because the
integer input function doesn't recognize boolean literal values as
valid.
Instead use the boolean-to-integer cast function for coercion in that
case so that using integer or domains thereof as type for EXISTS
columns works. Note that coercion for ON ERROR values TRUE and FALSE
already works like that because the parser creates a cast expression
including the cast function, but the coercion of the actual result
value is not handled by the parser.
Tests by Jian He.
Reported-by: Jian He <jian.universality@gmail.com>
Author: Jian He <jian.universality@gmail.com>
Author: Amit Langote <amitlangote09@gmail.com>
Discussion: https://postgr.es/m/CACJufxEo4sUjKCYtda0_qt9tazqqKPmF1cqhW9KBOUeJFqQd2g@mail.gmail.com
Backpatch-through: 17
Move responsibility of generating the cancel key to the backend
process. The cancel key is now generated after forking, and the
backend advertises it in the ProcSignal array. When a cancel request
arrives, the backend handling it scans the ProcSignal array to find
the target pid and cancel key. This is similar to how this previously
worked in the EXEC_BACKEND case with the ShmemBackendArray, just
reusing the ProcSignal array.
One notable change is that we no longer generate cancellation keys for
non-backend processes. We generated them before just to prevent a
malicious user from canceling them; the keys for non-backend processes
were never actually given to anyone. There is now an explicit flag
indicating whether a process has a valid key or not.
I wrote this originally in preparation for supporting longer cancel
keys, but it's a nice cleanup on its own.
Reviewed-by: Jelte Fennema-Nio
Discussion: https://www.postgresql.org/message-id/508d0505-8b7a-4864-a681-e7e5edfe32aa@iki.fi
In try_partitionwise_join, we aim to break down the join between two
partitioned relations into joins between matching partitions. To
achieve this, we iterate through each pair of partitions from the two
joining relations and create child-join relations for them. With
potentially thousands of partitions, the local objects allocated in
each iteration can accumulate significant memory usage. Therefore, we
opt to eagerly free these local objects at the end of each iteration.
In line with this approach, this patch frees the bitmap set that
represents the relids of child-join relations at the end of each
iteration. Additionally, it modifies build_child_join_rel() to reuse
the AppendRelInfo structures generated within each iteration.
Author: Ashutosh Bapat
Reviewed-by: David Christensen, Richard Guo
Discussion: https://postgr.es/m/CAExHW5s4EqY43oB=ne6B2=-xLgrs9ZGeTr1NXwkGFt2j-OmaQQ@mail.gmail.com
There were quite a few places where we either had a non-NUL-terminated
string or a text Datum which we needed to call escape_json() on. Many of
these places required that a temporary string was created due to the fact
that escape_json() needs a NUL-terminated cstring. For text types, those
first had to be converted to cstring before calling escape_json() on them.
Here we introduce two new functions to make escaping JSON more optimal:
escape_json_text() can be given a text Datum to append onto the given
buffer. This is more optimal as it foregoes the need to convert the text
Datum into a cstring. A temporary allocation is only required if the text
Datum needs to be detoasted.
escape_json_with_len() can be used when the length of the cstring is
already known or the given string isn't NUL-terminated. Having this
allows various places which were creating a temporary NUL-terminated
string to just call escape_json_with_len() without any temporary memory
allocations.
Discussion: https://postgr.es/m/CAApHDvpLXwMZvbCKcdGfU9XQjGCDm7tFpRdTXuB9PVgpNUYfEQ@mail.gmail.com
Reviewed-by: Melih Mutlu, Heikki Linnakangas
When a standby is promoted, CleanupAfterArchiveRecovery() may decide
to rename the final WAL file from the old timeline by adding ".partial"
to the name. If WAL summarization is enabled and this file is renamed
before its partial contents are summarized, WAL summarization breaks:
the summarizer gets stuck at that point in the WAL stream and just
errors out.
To fix that, first make the startup process wait for WAL summarization
to catch up before renaming the file. Generally, this should be quick,
and if it's not, the user can shut off summarize_wal and try again.
To make this fix work, also teach the WAL summarizer that after a
promotion has occurred, no more WAL can appear on the previous
timeline: previously, the WAL summarizer wouldn't switch to the new
timeline until we actually started writing WAL there, but that meant
that when the startup process was waiting for the WAL summarizer, it
was waiting for an action that the summarizer wasn't yet prepared to
take.
In the process of fixing these bugs, I realized that the logic to wait
for WAL summarization to catch up was spread out in a way that made
it difficult to reuse properly, so this code refactors things to make
it easier.
Finally, add a test case that would have caught this bug and the
previously-fixed bug that WAL summarization sometimes needs to back up
when the timeline changes.
Discussion: https://postgr.es/m/CA+TgmoZGEsZodXC4f=XZNkAeyuDmWTSkpkjCEOcF19Am0mt_OA@mail.gmail.com
Commit 274bbced85383e831dde accidentally placed the pg_config.h.in
for SSL_CTX_set_num_tickets on the wrong line wrt where autoheader
places it. Fix by re-arranging and backpatch to the same level as
the original commit.
Reported-by: Marina Polyakova <m.polyakova@postgrespro.ru>
Discussion: https://postgr.es/m/48cebe8c3eaf308bae253b1dbf4e4a75@postgrespro.ru
Backpatch-through: v12
The new test tests the libpq fallback behavior on an early error,
which was fixed in the previous commit.
This adds an IS_INJECTION_POINT_ATTACHED() macro, to allow writing
injected test code alongside the normal source code. In principle, the
new test could've been implemented by an extra test module with a
callback that sets the FrontendProtocol global variable, but I think
it's more clear to have the test code right where the injection point
is, because it has pretty intimate knowledge of the surrounding
context it runs in.
Reviewed-by: Michael Paquier
Discussion: https://www.postgresql.org/message-id/CAOYmi%2Bnwvu21mJ4DYKUa98HdfM_KZJi7B1MhyXtnsyOO-PB6Ww%40mail.gmail.com
Commit 86db52a506 changed the locking of injection points to use only
atomic ops and spinlocks, to make it possible to define injection
points in processes that don't have a PGPROC entry (yet). However, it
didn't work in EXEC_BACKEND mode, because the pointer to shared memory
area was not initialized until the process "attaches" to all the
shared memory structs. To fix, pass the pointer to the child process
along with other global variables that need to be set up early.
Backpatch-through: 17
OpenSSL supports two types of session tickets for TLSv1.3, stateless
and stateful. The option we've used only turns off stateless tickets
leaving stateful tickets active. Use the new API introduced in 1.1.1
to disable all types of tickets.
Backpatch to all supported versions.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reported-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20240617173803.6alnafnxpiqvlh3g@awork3.anarazel.de
Backpatch-through: v12
This change allows these functions to be called using named-argument
notation, which can be helpful for readability, particularly for
the ones with many arguments.
There was considerable debate about exactly which names to use,
but in the end we settled on the names already shown in our
documentation table 9.10.
The citext extension provides citext-aware versions of some of
these functions, so add argument names to those too.
In passing, fix table 9.10's syntax synopses for regexp_match,
which were slightly wrong about which combinations of arguments
are allowed.
Jian He, reviewed by Dian Fay and others
Discussion: https://postgr.es/m/CACJufxG3NFKKsh6x4fRLv8h3V-HvN4W5dA=zNKMxsNcDwOKang@mail.gmail.com
"path" provides a reliable method of determining the parent/child
relationships between memory contexts. Previously this could be done in
a non-reliable way by writing a recursive query and joining the "parent"
and "name" columns. This wasn't reliable as the names were not unique,
which could result in joining to the wrong parent.
To make this reliable, "path" stores an array of numerical identifiers
starting with the identifier for TopLevelMemoryContext. It contains an
element for each intermediate parent between that and the current context.
Incompatibility: Here we also adjust the "level" column to make it
1-based rather than 0-based. A 1-based level provides a convenient way
to access elements in the "path" array. e.g. path[level] gives the
identifier for the current context.
Identifiers are not stable across multiple evaluations of the view. In
an attempt to make these more stable for ad-hoc queries, the identifiers
are assigned breadth-first. Contexts closer to TopLevelMemoryContext
are less likely to change between queries and during queries.
Author: Melih Mutlu <m.melihmutlu@gmail.com>
Discussion: https://postgr.es/m/CAGPVpCThLyOsj3e_gYEvLoHkr5w=tadDiN_=z2OwsK3VJppeBA@mail.gmail.com
Reviewed-by: Andres Freund, Stephen Frost, Atsushi Torikoshi,
Reviewed-by: Michael Paquier, Robert Haas, David Rowley
Previously, TidStoreIterateNext() would expand the set of offsets for
each block into an internal buffer that it overwrote each time. In
order to be able to collect the offsets for multiple blocks before
working with them, change the contract. Now, the offsets are obtained
by a separate call to TidStoreGetBlockOffsets(), which can be called at
a later time. TidStoreIteratorResult objects are safe to copy and store
in a queue.
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/CAAKRu_bbkmwAzSBgnezancgJeXrQZXy4G4kBTd+5=cr86H5yew@mail.gmail.com
The two_phase option is controlled by both the publisher (as a slot
option) and the subscriber (as a subscription option), so the slot option
must also be modified.
Changing the 'two_phase' option for a subscription from 'true' to 'false'
is permitted only when there are no pending prepared transactions
corresponding to that subscription. Otherwise, the changes of already
prepared transactions can be replicated again along with their corresponding
commit leading to duplicate data or errors.
To avoid data loss, the 'two_phase' option for a subscription can only be
changed from 'false' to 'true' once the initial data synchronization is
completed. Therefore this is performed later by the logical replication worker.
Author: Hayato Kuroda, Ajin Cherian, Amit Kapila
Reviewed-by: Peter Smith, Hou Zhijie, Amit Kapila, Vitaly Davydov, Vignesh C
Discussion: https://postgr.es/m/8fab8-65d74c80-1-2f28e880@39088166
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
This fixes warnings from -Wmissing-variable-declarations (not yet part
of the standard warning options) under EXEC_BACKEND. The
NON_EXEC_STATIC variables need a suitable declaration in a header file
under EXEC_BACKEND.
Also fix the inconsistent application of the volatile qualifier for
PMSignalState, which was revealed by this change.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/flat/e0a62134-83da-4ba4-8cdb-ceb0111c95ce@eisentraut.org
slru.h described incorrectly how SLRU segment names are formatted
depending on the segment number and if long or short segment names are
used. This commit closes the gap with a better description, fitting
with the reality.
Reported-by: Noah Misch
Author: Aleksander Alekseev
Discussion: https://postgr.es/m/20240626002747.dc.nmisch@google.com
Backpatch-through: 17
In the case of a parallel plan, when computing the number of tuples
processed per worker, we divide the total number of tuples by the
parallel_divisor obtained from get_parallel_divisor(), which accounts
for the leader's contribution in addition to the number of workers.
Accordingly, when estimating the number of tuples for gather (merge)
nodes, we should multiply the number of tuples per worker by the same
parallel_divisor to reverse the division. However, currently we use
parallel_workers rather than parallel_divisor for the multiplication.
This could result in an underestimation of the number of tuples for
gather (merge) nodes, especially when there are fewer than four
workers.
This patch fixes this issue by using the same parallel_divisor for the
multiplication. There is one ensuing plan change in the regression
tests, but it looks reasonable and does not compromise its original
purpose of testing parallel-aware hash join.
In passing, this patch removes an unnecessary assignment for path.rows
in create_gather_merge_path, and fixes an uninitialized-variable issue
in generate_useful_gather_paths.
No backpatch as this could result in plan changes.
Author: Anthonin Bonnefoy
Reviewed-by: Rafia Sabih, Richard Guo
Discussion: https://postgr.es/m/CAO6_Xqr9+51NxgO=XospEkUeAg-p=EjAWmtpdcZwjRgGKJ53iA@mail.gmail.com
Previously, the code charged disable_cost for CurrentOfExpr, and then
subtracted disable_cost from the cost of a TID path that used
CurrentOfExpr as the TID qual, effectively disabling all paths except
that one. Now, we instead suppress generation of the disabled paths
entirely, and generate only the one that the executor will actually
understand.
With this approach, we do not need to rely on disable_cost being
large enough to prevent the wrong path from being chosen, and we
save some CPU cycle by avoiding generating paths that we can't
actually use. In my opinion, the code is also easier to understand
like this.
Patch by me. Review by Heikki Linnakangas.
Discussion: http://postgr.es/m/591b3596-2ea0-4b8e-99c6-fad0ef2801f5@iki.fi
Reaching that code would have required multiple processes performing
relation extension during recovery, which does not happen. That caller
has the persistence available, so pass it. This was dead code as soon
as commit 210622c60e1a9db2e2730140b8106ab57d259d15 added it.
Discussion: https://postgr.es/m/CAN55FZ0JKL6vk1xQp6rfOXiNFV1u1H0tJDPPGHWoiO3ea2Wc=A@mail.gmail.com
To do this, we must include the wal_level in the first WAL record
covered by each summary file; so add wal_level to struct Checkpoint
and the payload of XLOG_CHECKPOINT_REDO and XLOG_END_OF_RECOVERY.
This, in turn, requires bumping XLOG_PAGE_MAGIC and, since the
Checkpoint is also stored in the control file, also
PG_CONTROL_VERSION. It's not great to do that so late in the release
cycle, but the alternative seems to ship v17 without robust
protections against this scenario, which could result in corrupted
incremental backups.
A side effect of this patch is that, when a server with
wal_level=replica is started with summarize_wal=on for the first time,
summarization will no longer begin with the oldest WAL that still
exists in pg_wal, but rather from the first checkpoint after that.
This change should be harmless, because a WAL summary for a partial
checkpoint cycle can never make an incremental backup possible when
it would otherwise not have been.
Report by Fujii Masao. Patch by me. Review and/or testing by Jakub
Wartak and Fujii Masao.
Discussion: http://postgr.es/m/6e30082e-041b-4e31-9633-95a66de76f5d@oss.nttdata.com
This new macro is able to perform a direct lookup from the local cache
of injection points (refreshed each time a point is loaded or run),
without touching the shared memory state of injection points at all.
This works in combination with INJECTION_POINT_LOAD(), and it is better
than INJECTION_POINT() in a critical section due to the fact that it
would avoid all memory allocations should a concurrent detach happen
since a LOAD(), as it retrieves a callback from the backend-private
memory.
The documentation is updated to describe in more details how to use this
new macro with a load. Some tests are added to the module
injection_points based on a new SQL function that acts as a wrapper of
INJECTION_POINT_CACHED().
Based on a suggestion from Heikki Linnakangas.
Author: Heikki Linnakangas, Michael Paquier
Discussion: https://postgr.es/m/58d588d0-e63f-432f-9181-bed29313dece@iki.fi
Commit f4b54e1ed9, which introduced macros for protocol characters,
missed updating a few places. It also did not introduce macros for
messages sent from parallel workers to their leader processes.
This commit adds a new section in protocol.h for those.
Author: Aleksander Alekseev
Discussion: https://postgr.es/m/CAJ7c6TNTd09AZq8tGaHS3LDyH_CCnpv0oOz2wN1dGe8zekxrdQ%40mail.gmail.com
Backpatch-through: 17
Previously, CREATE MATERIALIZED VIEW ... WITH DATA populated the MV
the same way as CREATE TABLE ... AS.
Instead, reuse the REFRESH logic, which locks down security-restricted
operations and restricts the search_path. This reduces the chance that
a subsequent refresh will fail.
Reported-by: Noah Misch
Backpatch-through: 17
Discussion: https://postgr.es/m/20240630222344.db.nmisch@google.com
