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Split ProcSleep into two functions: JoinWaitQueue and ProcSleep.
JoinWaitQueue is called while holding the partition lock, and inserts
the current process to the wait queue, while ProcSleep() does the
actual sleeping. ProcSleep() is now called without holding the
partition lock, and it no longer re-acquires the partition lock before
returning. That makes the wakeup a little cheaper. Once upon a time,
re-acquiring the partition lock was needed to prevent a signal handler
from longjmping out at a bad time, but these days our signal handlers
just set flags, and longjmping can only happen at points where we
explicitly run CHECK_FOR_INTERRUPTS().
If JoinWaitQueue detects an "early deadlock" before even joining the
wait queue, it returns without changing the shared lock entry, leaving
the cleanup of the shared lock entry to the caller. This makes the
handling of an early deadlock the same as the dontWait=true case.
One small user-visible side-effect of this refactoring is that we now
only set the 'ps' title to say "waiting" when we actually enter the
sleep, not when the lock is skipped because dontWait=true, or when a
deadlock is detected early before entering the sleep.
This eliminates the 'lockAwaited' global variable in proc.c, which was
largely redundant with 'awaitedLock' in lock.c
Note: Updating the local lock table is now the caller's responsibility.
JoinWaitQueue and ProcSleep are now only responsible for modifying the
shared state. Seems a little nicer that way.
Based on Thomas Munro's earlier patch and observation that ProcSleep
doesn't really need to re-acquire the partition lock.
Reviewed-by: Maxim Orlov
Discussion: https://www.postgresql.org/message-id/7c2090cd-a72a-4e34-afaa-6dd2ef31440e@iki.fi
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LockAcquire is a long and complex function. Pushing more stuff to its
subroutines makes it a little more manageable.
Reviewed-by: Maxim Orlov
Discussion: https://www.postgresql.org/message-id/7c2090cd-a72a-4e34-afaa-6dd2ef31440e@iki.fi
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Previously, ProcSleep()'s caller was responsible for setting
MyProc->heldLocks, and we had comments to remind about that. But it
seems simpler to make ProcSleep() itself responsible for it.
ProcSleep() already set the other info about the lock its waiting for
(waitLock, waitProcLock and waitLockMode), so it is natural for it to
set heldLocks too.
Reviewed-by: Maxim Orlov
Discussion: https://www.postgresql.org/message-id/7c2090cd-a72a-4e34-afaa-6dd2ef31440e@iki.fi
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We reach this case also e.g. when a deadlock is detected, not only
when we run out of memory.
Reviewed-by: Maxim Orlov
Discussion: https://www.postgresql.org/message-id/7c2090cd-a72a-4e34-afaa-6dd2ef31440e@iki.fi
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This is in preparation for replacing Latches with a new abstraction.
That's still work in progress, but this seems a little tidier anyway,
so let's get this refactoring out of the way already.
Discussion: https://www.postgresql.org/message-id/391abe21-413e-4d91-a650-b663af49500c%40iki.fi
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After a closer lookup, this makes the all-zero check of the page more
expensive, so let's remove the new function call in bufpage.c. The
maths of the check were also incorrect, checking that the page was full
of zeros only for the first 1kB.
This brings back the code to the state it was at 49d6c7d8daba.
Per discussion with David Rowley and Bertrand Drouvot.
Discussion: https://postgr.es/m/CAApHDvrXzPAr3FxoBuB7b3D-okNoNA2jxLun1rW8Yw5wkbqusw@mail.gmail.com
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This new function tests if a memory region starting at a given location
for a defined length is made only of zeroes. This unifies in a single
path the all-zero checks that were happening in a couple of places of
the backend code:
- For pgstats entries of relation, checkpointer and bgwriter, where
some "all_zeroes" variables were previously used with memcpy().
- For all-zero buffer pages in PageIsVerifiedExtended().
This new function uses the same forward scan as the check for all-zero
buffer pages, applying it to the three pgstats paths mentioned above.
Author: Bertrand Drouvot
Reviewed-by: Peter Eisentraut, Heikki Linnakangas, Peter Smith
Discussion: https://postgr.es/m/ZupUDDyf1hHI4ibn@ip-10-97-1-34.eu-west-3.compute.internal
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as determined by IWYU
These are mostly issues that are new since commit dbbca2cf299.
Discussion: https://www.postgresql.org/message-id/flat/0df1d5b1-8ca8-4f84-93be-121081bde049%40eisentraut.org
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Previously, GetLockStatusData() checked all slots for every backend
to gather fast-path lock data, which could be inefficient. This commit
refactors it by skipping backends with PID=0 (since they don't hold
fast-path locks) and skipping groups with no registered fast-path locks,
improving efficiency.
This refactoring is particularly beneficial, for example when
max_connections and max_locks_per_transaction are set high,
as it reduces unnecessary checks across numerous slots.
Author: Fujii Masao
Reviewed-by: Bertrand Drouvot
Discussion: https://postgr.es/m/a0a00c44-31e9-4c67-9846-fb9636213ac9@oss.nttdata.com
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3c5db1d6b implemented the pg_wal_replay_wait() stored procedure. Due to
the patch development history, the implementation resided in
src/backend/commands/waitlsn.c (src/include/commands/waitlsn.h for headers).
014f9f34d moved pg_wal_replay_wait() itself to
src/backend/access/transam/xlogfuncs.c near to the WAL-manipulation functions.
But most of the implementation stayed in place.
The code in src/backend/commands/waitlsn.c has nothing to do with commands,
but is related to WAL. So, this commit moves this code into
src/backend/access/transam/xlogwait.c (src/include/access/xlogwait.h for
headers).
Reported-by: Peter Eisentraut
Discussion: https://postgr.es/m/18c0fa64-0475-415e-a1bd-665d922c5201%40eisentraut.org
Reviewed-by: Pavel Borisov
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We haven't generated those for a long time.
Discussion: https://www.postgresql.org/message-id/b439edfc-c5e5-43a9-802d-4cb51ec20646@iki.fi
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The finished transaction list can contain XIDs that are older than the
serializable global xmin. It's a short-lived state;
ClearOldPredicateLocks() removes any such transactions from the list,
and it's called whenever the global xmin advances. But if another
backend calls SummarizeOldestCommittedSxact() in that window, it will
call SerialAdd() on an XID that's older than the global xmin, or if
there are no more transactions running, when global xmin is
invalid. That trips the assertion in SerialAdd().
Fixes bug #18658 reported by Andrew Bille. Thanks to Alexander Lakhin
for analysis. Backpatch to all versions.
Discussion: https://www.postgresql.org/message-id/18658-7dab125ec688c70b%40postgresql.org
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Author: Junwang Zhao
Discussion: https://postgr.es/m/CAEG8a3L5YjxXCjx0LhkwHdDGsNgpFGEqH7SqtXRPNP+dwFMVZQ@mail.gmail.com
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With real AIO it doesn't make sense to cross segment boundaries with one
IO. Add smgrmaxcombine() to allow upper layers to query which buffers can be
merged.
We could continue to cross segment boundaries when not using AIO, but it
doesn't really make sense, because md.c will never be able to perform the read
across the segment boundary in one system call. Which means we'll mark more
buffers as undergoing IO than really makes sense - if another backend desires
to read the same blocks, it'll be blocked longer than necessary. So it seems
better to just never cross the boundary.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/1f6b50a7-38ef-4d87-8246-786d39f46ab9@iki.fi
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As pg_flush_data() doesn't do anything with fsync disabled, there's no point
in tracking the buffer for writeback. Arguably the better fix would be to
change pg_flush_data() to flush data even with fsync off, but that's a
behavioral change, whereas this is just a small optimization.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://postgr.es/m/1f6b50a7-38ef-4d87-8246-786d39f46ab9@iki.fi
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This seems nicer than having to duplicate the logic between
InitProcess() and ProcKill() for which child processes have a
PMChildFlags slot.
Move the MarkPostmasterChildActive() call earlier in InitProcess(),
out of the section protected by the spinlock.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/a102f15f-eac4-4ff2-af02-f9ff209ec66f@iki.fi
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The current use always releases this locktag. A planned use will
continue that intent. It will involve more areas of code, making unlock
omissions easier. Warn under debug_assertions, like we do for various
resource leaks. Back-patch to v12 (all supported versions), the plan
for the commit of the new use.
Reviewed by Heikki Linnakangas.
Discussion: https://postgr.es/m/20240512232923.aa.nmisch@google.com
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Commit c4d5cb71d229 introduced a couple asserts in the fast-path locking
code, upsetting Coverity.
The assert in InitProcGlobal() is clearly wrong, as it assigns instead
of checking the value. This is harmless, but doesn't check anything.
The asserts in FAST_PATH_ macros are written as if for signed values,
but the macros are only called for unsigned ones. That makes the check
for (val >= 0) useless. Checks written as ((uint32) x < max) work for
both signed and unsigned values. Negative values should wrap to values
greater than INT32_MAX.
Per Coverity, report by Tom Lane.
Reported-by: Tom Lane
Discussion: https://postgr.es/m/2891628.1727019959@sss.pgh.pa.us
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Replace the fixed-size array of fast-path locks with arrays, sized on
startup based on max_locks_per_transaction. This allows using fast-path
locking for workloads that need more locks.
The fast-path locking introduced in 9.2 allowed each backend to acquire
a small number (16) of weak relation locks cheaply. If a backend needs
to hold more locks, it has to insert them into the shared lock table.
This is considerably more expensive, and may be subject to contention
(especially on many-core systems).
The limit of 16 fast-path locks was always rather low, because we have
to lock all relations - not just tables, but also indexes, views, etc.
For planning we need to lock all relations that might be used in the
plan, not just those that actually get used in the final plan. So even
with rather simple queries and schemas, we often need significantly more
than 16 locks.
As partitioning gets used more widely, and the number of partitions
increases, this limit is trivial to hit. Complex queries may easily use
hundreds or even thousands of locks. For workloads doing a lot of I/O
this is not noticeable, but for workloads accessing only data in RAM,
the access to the shared lock table may be a serious issue.
This commit removes the hard-coded limit of the number of fast-path
locks. Instead, the size of the fast-path arrays is calculated at
startup, and can be set much higher than the original 16-lock limit.
The overall fast-path locking protocol remains unchanged.
The variable-sized fast-path arrays can no longer be part of PGPROC, but
are allocated as a separate chunk of shared memory and then references
from the PGPROC entries.
The fast-path slots are organized as a 16-way set associative cache. You
can imagine it as a hash table of 16-slot "groups". Each relation is
mapped to exactly one group using hash(relid), and the group is then
processed using linear search, just like the original fast-path cache.
With only 16 entries this is cheap, with good locality.
Treating this as a simple hash table with open addressing would not be
efficient, especially once the hash table gets almost full. The usual
remedy is to grow the table, but we can't do that here easily. The
access would also be more random, with worse locality.
The fast-path arrays are sized using the max_locks_per_transaction GUC.
We try to have enough capacity for the number of locks specified in the
GUC, using the traditional 2^n formula, with an upper limit of 1024 lock
groups (i.e. 16k locks). The default value of max_locks_per_transaction
is 64, which means those instances will have 64 fast-path slots.
The main purpose of the max_locks_per_transaction GUC is to size the
shared lock table. It is often set to the "average" number of locks
needed by backends, with some backends using significantly more locks.
This should not be a major issue, however. Some backens may have to
insert locks into the shared lock table, but there can't be too many of
them, limiting the contention.
The only solution is to increase the GUC, even if the shared lock table
already has sufficient capacity. That is not free, especially in terms
of memory usage (the shared lock table entries are fairly large). It
should only happen on machines with plenty of memory, though.
In the future we may consider a separate GUC for the number of fast-path
slots, but let's try without one first.
Reviewed-by: Robert Haas, Jakub Wartak
Discussion: https://postgr.es/m/510b887e-c0ce-4a0c-a17a-2c6abb8d9a5c@enterprisedb.com
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Commits 041b9680 and 6377e12a changed the interface of
scan_analyze_next_block() to take a ReadStream instead of a BlockNumber
and a BufferAccessStrategy, and to return a value to indicate when the
stream has run out of blocks.
This caused integration problems for at least one known extension that
uses specially encoded BlockNumber values that map to different
underlying storage, because acquire_sample_rows() sets up the stream so
that read_stream_next_buffer() reads blocks from the main fork of the
relation's SMgrRelation.
Provide read_stream_next_block(), as a way for such an extension to
access the stream of raw BlockNumbers directly and forward them to its
own ReadBuffer() calls after decoding, as it could in earlier releases.
The new function returns the BlockNumber and BufferAccessStrategy that
were previously passed directly to scan_analyze_next_block().
Alternatively, an extension could wrap the stream of BlockNumbers in
another ReadStream with a callback that performs any decoding required
to arrive at real storage manager BlockNumber values, so that it could
benefit from the I/O combining and concurrency provided by
read_stream.c.
Another class of table access method that does nothing in
scan_analyze_next_block() because it is not block-oriented could use
this function to control the number of block sampling loops. It could
match the previous behavior with "return read_stream_next_block(stream,
&bas) != InvalidBlockNumber".
Ongoing work is expected to provide better ANALYZE support for table
access methods that don't behave like heapam with respect to storage
blocks, but that will be for future releases.
Back-patch to 17.
Reported-by: Mats Kindahl <mats@timescale.com>
Reviewed-by: Mats Kindahl <mats@timescale.com>
Discussion: https://postgr.es/m/CA%2B14425%2BCcm07ocG97Fp%2BFrD9xUXqmBKFvecp0p%2BgV2YYR258Q%40mail.gmail.com
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myLargeObjectExists() and LargeObjectExists() had nearly identical code,
except for handling snapshots. This commit renames myLargeObjectExists()
to LargeObjectExistsWithSnapshot() and refactors LargeObjectExists()
to call it internally, reducing duplication.
Author: Yugo Nagata
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/20240702163444.ab586f6075e502eb84f11b1a@sranhm.sraoss.co.jp
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This commit updates a couple of error messages around control file data,
GUCs and server settings, unifying to the same message where possible.
This reduces the translation burden a bit.
Author: Peter Smith
Discussion: https://postgr.es/m/CAHut+Pv-kSN8SkxSdoHano_wPubqcg5789ejhCDZAcLFceBR-w@mail.gmail.com
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This is a continuation of 17974ec25946. More quotes are applied to
GUC names in error messages and hints, taking care of what seems to be
all the remaining holes currently in the tree for the GUCs.
Author: Peter Smith
Discussion: https://postgr.es/m/CAHut+Pv-kSN8SkxSdoHano_wPubqcg5789ejhCDZAcLFceBR-w@mail.gmail.com
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This term was using an inconsistent casing between the code and the
documentation, using "CommitTsSLRU" in wait_event_names.txt and
"CommitTSSLRU" in the code.
Let's update the term in the code to reflect what's in the
documentation, "CommitTs" being more commonly used, so as
pg_stat_activity shows the same term as the documentation.
Oversight in 53c2a97a9266.
Author: Alexander Lakhin
Discussion: https://postgr.es/m/f7e514cf-2446-21f1-a5d2-8c089a6e2168@gmail.com
Backpatch-through: 17
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Commit 6654bb920 added macOS's equivalent of POSIX_FADV_WILLNEED, and
changed some explicit references to posix_fadvise to use this more
general name for the concept. Update some remaining references.
Reviewed-by: Peter Eisentraut <peter@eisentraut.org>
Discussion: https://postgr.es/m/0827edec-1317-4917-a186-035eb1e3241d%40eisentraut.org
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This replaces two functions for iterating over all blocks in a range. A
pending patch will use this instead of adding a third.
Nazir Bilal Yavuz
Discussion: https://postgr.es/m/20240820184742.f2.nmisch@google.com
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The typos in 005_negotiate_encryption.pl and pg_combinebackup.c
shall be backported to v17 where they were introduced.
Backpatch-through: v17
Discussion: https://postgr.es/m/Ztaj7BkN4658OMxF@paquier.xyz
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Author: Alexander Lakhin
Discussion: https://postgr.es/m/f7e514cf-2446-21f1-a5d2-8c089a6e2168@gmail.com
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Similarly to 2065ddf5e34c, this introduces a define for "pg_tblspc".
This makes the style more consistent with the existing PG_STAT_TMP_DIR,
for example.
There is a difference with the other cases with the introduction of
PG_TBLSPC_DIR_SLASH, required in two places for recovery and backups.
Author: Bertrand Drouvot
Reviewed-by: Ashutosh Bapat, Álvaro Herrera, Yugo Nagata, Michael
Paquier
Discussion: https://postgr.es/m/ZryVvjqS9SnV1GPP@ip-10-97-1-34.eu-west-3.compute.internal
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Commit b5a9b18c introduced block streaming infrastructure with a special
fast path for all-cached scans, and commit b7b0f3f2 connected the
infrastructure up to sequential scans. One of the fast path
micro-optimizations had an unintended consequence: it interfered with
parallel sequential scan's block range allocator (from commit 56788d21),
which has its own ramp-up and ramp-down algorithm when handing out
groups of pages to workers. A scan of an all-cached table could give
extra blocks to one worker, when others had finished. In some plans
(probably already very bad plans, such as the one reported by
Alexander), the unfairness could be magnified.
An internal buffer of 16 block numbers is removed, keeping just a single
block buffer for technical reasons.
Back-patch to 17.
Reported-by: Alexander Lakhin <exclusion@gmail.com>
Discussion: https://postgr.es/m/63a63690-dd92-c809-0b47-af05459e95d1%40gmail.com
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To make them follow the usual naming convention where
FoobarShmemSize() calculates the amount of shared memory needed by
Foobar subsystem, and FoobarShmemInit() performs the initialization.
I didn't rename CreateLWLocks() and InitShmmeIndex(), because they are
a little special. They need to be called before any of the other
ShmemInit() functions, because they set up the shared memory
bookkeeping itself. I also didn't rename InitProcGlobal(), because
unlike other Shmeminit functions, it's not called by individual
backends.
Reviewed-by: Andreas Karlsson
Discussion: https://www.postgresql.org/message-id/c09694ff-2453-47e5-b26c-32a16cd75ce6@iki.fi
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Split the shared and local initialization to separate functions, and
follow the common naming conventions. With this, we no longer create
the LockMethodLocalHash hash table in the postmaster process, which
was always pointless.
Reviewed-by: Andreas Karlsson
Discussion: https://www.postgresql.org/message-id/c09694ff-2453-47e5-b26c-32a16cd75ce6@iki.fi
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The new code path (commit 6654bb92047) should call FileAccess() first,
like the posix_fadvise() path.
Reported-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/0827edec-1317-4917-a186-035eb1e3241d%40eisentraut.org
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macOS doesn't have posix_fadvise(), but fcntl() with the F_RDADVISE
command does the same thing.
Some related documentation has been generalized to not mention
posix_advise() specifically anymore.
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/0827edec-1317-4917-a186-035eb1e3241d%40eisentraut.org
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The commit was "Provide API for streaming relation data.".
Reported-by: Nazir Bilal Yavuz
Discussion: https://postgr.es/m/CAN55FZ3KsZ2faZs1sK5J0W+_8B3myB232CfLYGie4u4BBMwP3g@mail.gmail.com
Backpatch-through: master
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And improve the comments.
Backpatch to v17 where this was introduced.
Reviewed-by: Noah Misch
Discussion: https://www.postgresql.org/message-id/cac7d1b6-8358-40be-af0b-21bc9b27d34c@iki.fi
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Previously, (auto)analyze used global variables VacuumPageHit,
VacuumPageMiss, and VacuumPageDirty to track buffer usage. However,
pgBufferUsage provides a more generic way to track buffer usage with
support functions.
This change replaces those global variables with pgBufferUsage in
analyze. Since analyze was the sole user of those variables, it
removes their declarations. Vacuum previously used those variables but
replaced them with pgBufferUsage as part of a bug fix, commit
5cd72cc0c.
Additionally, it adjusts the buffer usage message in both vacuum and
analyze for better consistency.
Author: Anthonin Bonnefoy
Reviewed-by: Masahiko Sawada, Michael Paquier
Discussion: https://postgr.es/m/CAO6_Xqr__kTTCLkftqS0qSCm-J7_xbRG3Ge2rWhucxQJMJhcRA%40mail.gmail.com
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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
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A later change will require atomic support, so it wouldn't make sense
for a hypothetical new system not to be able to implement spinlocks.
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
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Commit 9d9b9d46f3 added spinlocks to protect the fields in ProcSignal
flags, but in EmitProcSignalBarrier(), the spinlock was released
twice. With most spinlock implementations, releasing a lock that's not
held is not easy to notice, because most of the time it does nothing,
but if the spinlock was concurrently acquired by another process, it
could lead to more serious issues. Fortunately, with the
--disable-spinlocks emulation implementation, it caused more visible
failures.
In the passing, fix a type in comment and add an assertion that the
procNumber passed to SendProcSignal looks valid.
Discussion: https://www.postgresql.org/message-id/b8ce284c-18a2-4a79-afd3-1991a2e7d246@iki.fi
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Per buildfarm member 'sifaka':
procsignal.c:87:3: error: redefinition of typedef 'ProcSignalHeader' is a C11 feature [-Werror,-Wtypedef-redefinition]
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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
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Commit c5315f4f44 replaced smgr_fsm_nblocks and smgr_vm_nblocks with
smgr_cached_nblocks, but forgot to update this comment.
Author: Kirill Reshke
Discussion: https://www.postgresql.org/message-id/CALdSSPh9VA6SDSVjrcmSPEYramf%2BrFisK7GqJo1dtRnD3vddmA@mail.gmail.com
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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
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Commit 8720a15e9ab121e49174d889eaeafae8ac89de7b added the wrong name.
Nazir Bilal Yavuz
Discussion: https://postgr.es/m/20240720181405.5a.nmisch@google.com
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clog.c, async.c and predicate.c included some SLRU page numbers still
handled as 4-byte integers, while int64 should be used for this purpose.
These holes have been introduced in 4ed8f0913bfd, that has introduced
the use of 8-byte integers for SLRU page numbers, still forgot about the
code paths updated by this commit.
Reported-by: Noah Misch
Author: Aleksander Alekseev, Michael Paquier
Discussion: https://postgr.es/m/20240626002747.dc.nmisch@google.com
Backpatch-through: 17
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While this doesn't significantly change runtime now, it arranges for
STRATEGY=WAL_LOG to benefit automatically from future optimizations to
the read_stream subsystem. For large tables in the template database,
this does read 16x as many bytes per system call. Platforms with high
per-call overhead, if any, may see an immediate benefit.
Nazir Bilal Yavuz
Discussion: https://postgr.es/m/CAN55FZ0JKL6vk1xQp6rfOXiNFV1u1H0tJDPPGHWoiO3ea2Wc=A@mail.gmail.com
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Currently read stream object can be created only by using Relation.
Nazir Bilal Yavuz
Discussion: https://postgr.es/m/CAN55FZ0JKL6vk1xQp6rfOXiNFV1u1H0tJDPPGHWoiO3ea2Wc=A@mail.gmail.com
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There are checks in PinBufferForBlock() function to set persistence of
the relation. This function is called for each block in the relation.
Instead, set persistence of the relation before PinBufferForBlock().
Nazir Bilal Yavuz
Discussion: https://postgr.es/m/CAN55FZ0JKL6vk1xQp6rfOXiNFV1u1H0tJDPPGHWoiO3ea2Wc=A@mail.gmail.com
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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
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