Provide a way for WaitEventSet to report that the remote peer has shut
down its socket, independently of whether there is any buffered data
remaining to be read. This works only on systems where the kernel
exposes that information, namely:
* WAIT_USE_POLL builds using POLLRDHUP, if available
* WAIT_USE_EPOLL builds using EPOLLRDHUP
* WAIT_USE_KQUEUE builds using EV_EOF
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Reviewed-by: Maksim Milyutin <milyutinma@gmail.com>
Discussion: https://postgr.es/m/77def86b27e41f0efcba411460e929ae%40postgrespro.ru
Previously, it was possible for DROP DATABASE, DROP TABLESPACE and ALTER
DATABASE SET TABLESPACE to fail because other backends still had file
handles open for dropped tables. Windows won't allow a directory
containing unlinked-but-still-open files to be unlinked. Tackle this
problem by forcing all backends to close all smgr fds. No change for
Unix systems, which don't suffer from the problem, but the new code path
can be tested by Unix-based developers by defining
USE_BARRIER_SMGRRELEASE explicitly.
It's possible that PROCSIGNAL_BARRIER_SMGRRELEASE will have more
bug-fixing applications soon (under discussion). Note that this is the
first user of the ProcSignalBarrier mechanism from commit 16a4e4aec. It
could in principle be back-patched as far as 14, but since field
complaints are rare and ProcSignalBarrier hasn't been battle-tested,
that seems like a bad idea. Fix in master only, where these failures
have started to show up in automated testing due to new tests.
Suggested-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Daniel Gustafsson <daniel@yesql.se>
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/CA+hUKGLdemy2gBm80kz20GTe6hNVwoErE8KwcJk6-U56oStjtg@mail.gmail.com
Commit 6a2a70a02 supposed that any platform having <sys/epoll.h>
would also have <sys/signalfd.h>. It turns out there are still a
few people using platforms where that's not so, so we'd better make
a separate configure probe for it. But since it took this long to
notice, I'm content with the decision to not have a separate code
path for epoll-only machines; we'll just fall back to using poll()
for these stragglers.
Per gripe from Gabriela Serventi. Back-patch to v14 where this
code came in.
Discussion: https://postgr.es/m/CAHOHWE-JjJDfcYuLAAEO7Jk07atFAU47z8TzHzg71gbC0aMy=g@mail.gmail.com
Previously, it was really easy to write code that accessed MaxBackends
before we'd actually initialized it, especially when coding up an
extension. To make this less error-prune, introduce a new function
GetMaxBackends() which should be used to obtain the correct value.
This will ERROR if called too early. Demote the global variable to
a file-level static, so that nobody can peak at it directly.
Nathan Bossart. Idea by Andres Freund. Review by Greg Sabino Mullane,
by Michael Paquier (who had doubts about the approach), and by me.
Discussion: http://postgr.es/m/20210802224204.bckcikl45uezv5e4@alap3.anarazel.de
Commit 8431e296ea reworked ProcArrayApplyRecoveryInfo to sort XIDs
before adding them to KnownAssignedXids. But the XIDs are sorted using
xidComparator, which compares the XIDs simply as uint32 values, not
logically. KnownAssignedXidsAdd() however expects XIDs in logical order,
and calls TransactionIdFollowsOrEquals() to enforce that. If there are
XIDs for which the two orderings disagree, an error is raised and the
recovery fails/restarts.
Hitting this issue is fairly easy - you just need two transactions, one
started before the 4B limit (e.g. XID 4294967290), the other sometime
after it (e.g. XID 1000). Logically (4294967290 <= 1000) but when
compared using xidComparator we try to add them in the opposite order.
Which makes KnownAssignedXidsAdd() fail with an error like this:
ERROR: out-of-order XID insertion in KnownAssignedXids
This only happens during replica startup, while processing RUNNING_XACTS
records to build the snapshot. Once we reach STANDBY_SNAPSHOT_READY, we
skip these records. So this does not affect already running replicas,
but if you restart (or create) a replica while there are transactions
with XIDs for which the two orderings disagree, you may hit this.
Long-running transactions and frequent replica restarts increase the
likelihood of hitting this issue. Once the replica gets into this state,
it can't be started (even if the old transactions are terminated).
Fixed by sorting the XIDs logically - this is fine because we're dealing
with normal XIDs (because it's XIDs assigned to backends) and from the
same wraparound epoch (otherwise the backends could not be running at
the same time on the primary node). So there are no problems with the
triangle inequality, which is why xidComparator compares raw values.
Investigation and root cause analysis by Abhijit Menon-Sen. Patch by me.
This issue is present in all releases since 9.4, however releases up to
9.6 are EOL already so backpatch to 10 only.
Reviewed-by: Abhijit Menon-Sen
Reviewed-by: Alvaro Herrera
Backpatch-through: 10
Discussion: https://postgr.es/m/36b8a501-5d73-277c-4972-f58a4dce088a%40enterprisedb.com
Previously, invoking pg_terminate_backend() or pg_cancel_backend()
with the postmaster PID produced a "PID XXXX is not a PostgresSQL
server process" warning, which does not make sense. Change to
"backend process" to make the message more exact.
Nathan Bossart, based on an idea from Bharath Rupireddy with
input from Tom Lane and Euler Taveira
Discussion: https://www.postgresql.org/message-id/flat/CALj2ACW7Rr-R7mBcBQiXWPp=JV5chajjTdudLiF5YcpW-BmHhg@mail.gmail.com
Standardize on xoroshiro128** as our basic PRNG algorithm, eliminating
a bunch of platform dependencies as well as fundamentally-obsolete PRNG
code. In addition, this API replacement will ease replacing the
algorithm again in future, should that become necessary.
xoroshiro128** is a few percent slower than the drand48 family,
but it can produce full-width 64-bit random values not only 48-bit,
and it should be much more trustworthy. It's likely to be noticeably
faster than the platform's random(), depending on which platform you
are thinking about; and we can have non-global state vectors easily,
unlike with random(). It is not cryptographically strong, but neither
are the functions it replaces.
Fabien Coelho, reviewed by Dean Rasheed, Aleksander Alekseev, and myself
Discussion: https://postgr.es/m/alpine.DEB.2.22.394.2105241211230.165418@pseudo
While determining xid horizons, we skip over backends that are running
Vacuum. We also ignore Create Index Concurrently, or Reindex Concurrently
for the purposes of computing Xmin for Vacuum. But we were not setting the
flags corresponding to these operations when they are performed in
parallel which was preventing Xid horizon from advancing.
The optimization related to skipping Create Index Concurrently, or Reindex
Concurrently operations was implemented in PG-14 but the fix is the same
for the Parallel Vacuum as well so back-patched till PG-13.
Author: Masahiko Sawada
Reviewed-by: Amit Kapila
Backpatch-through: 13
Discussion: https://postgr.es/m/CAD21AoCLQqgM1sXh9BrDFq0uzd3RBFKi=Vfo6cjjKODm0Onr5w@mail.gmail.com
Currently, lastOverflowedXid is never reset. It's just adjusted on new
transactions known to be overflowed. But if there are no overflowed
transactions for a long time, snapshots could be mistakenly marked as
suboverflowed due to wraparound.
This commit fixes this issue by resetting lastOverflowedXid when needed
altogether with KnownAssignedXids.
Backpatch to all supported versions.
Reported-by: Stan Hu
Discussion: https://postgr.es/m/CAMBWrQ%3DFp5UAsU_nATY7EMY7NHczG4-DTDU%3DmCvBQZAQ6wa2xQ%40mail.gmail.com
Author: Kyotaro Horiguchi, Alexander Korotkov
Reviewed-by: Stan Hu, Simon Riggs, Nikolay Samokhvalov, Andrey Borodin, Dmitry Dolgov
When replaying a transaction that held many exclusive locks on the
primary, a standby server's startup process would expend O(N^2)
effort on manipulating the list of locks. This code was fine when
written, but commit 1cff1b95a made repetitive list_delete_first()
calls inefficient, as explained in its commit message. Fix by just
iterating the list normally, and releasing storage only when done.
(This'd be inadequate if we needed to recover from an error occurring
partway through; but we don't.)
Back-patch to v13 where 1cff1b95a came in.
Nathan Bossart
Discussion: https://postgr.es/m/CD2F0E7F-9822-45EC-A411-AE56F14DEA9F@amazon.com
Do not update shm_mq's mq_bytes_written until we have written
an amount of data greater than 1/4th of the ring size, unless
the caller of shm_mq_send(v) requests a flush at the end of
the message. This reduces the number of calls to SetLatch(),
and also the number of CPU cache misses, considerably, and thus
makes shm_mq significantly faster.
Dilip Kumar, reviewed by Zhihong Yu and Tomas Vondra. Some
minor cosmetic changes by me.
Discussion: http://postgr.es/m/CAFiTN-tVXqn_OG7tHNeSkBbN+iiCZTiQ83uakax43y1sQb2OBA@mail.gmail.com
This runtime-computed GUC shows the number of huge pages required
for the server's main shared memory area, taking advantage of the
work done in 0c39c29 and 0bd305e. This is useful for users to estimate
the amount of huge pages required for a server as it becomes possible to
do an estimation without having to start the server and potentially
allocate a large chunk of shared memory.
The number of huge pages is calculated based on the existing GUC
huge_page_size if set, or by using the system's default by looking at
/proc/meminfo on Linux. There is nothing new here as this commit reuses
the existing calculation methods, and just exposes this information
directly to the user. The routine calculating the huge page size is
refactored to limit the number of files with platform-specific flags.
This new GUC's name was the most popular choice based on the discussion
done. This is only supported on Linux.
I have taken the time to test the change on Linux, Windows and MacOS,
though for the last two ones large pages are not supported. The first
one calculates correctly the number of pages depending on the existing
GUC huge_page_size or the system's default.
Thanks to Andres Freund, Robert Haas, Kyotaro Horiguchi, Tom Lane,
Justin Pryzby (and anybody forgotten here) for the discussion.
Author: Nathan Bossart
Discussion: https://postgr.es/m/F2772387-CE0F-46BF-B5F1-CC55516EB885@amazon.com
ProcArrayGroupClearXid function has a parameter named "proc",
but the same name was used for its local variables. This commit fixes
this variable shadowing, to improve code readability.
Back-patch to all supported versions, to make future back-patching
easy though this patch is classified as refactoring only.
Reported-by: Ranier Vilela
Author: Ranier Vilela, Aleksander Alekseev
https://postgr.es/m/CAEudQAqyoTZC670xWi6w-Oe2_Bk1bfu2JzXz6xRfiOUzm7xbyQ@mail.gmail.com
All size_t variables declared in procarray.c are actually int ones.
Let's use int instead of size_t for those variables. Which would
reduce Wsign-compare compiler warnings.
Back-patch to v14 where commit 941697c3c1 added size_t variables
in procarray.c, to make future back-patching easy though
this patch is classified as refactoring only.
Reported-by: Ranier Vilela
Author: Ranier Vilela, Aleksander Alekseev
https://postgr.es/m/CAEudQAqyoTZC670xWi6w-Oe2_Bk1bfu2JzXz6xRfiOUzm7xbyQ@mail.gmail.com
This runtime-computed GUC shows the size of the server's main shared
memory area, taking into account the amount of shared memory allocated
by extensions as this is calculated after processing
shared_preload_libraries.
Author: Nathan Bossart
Discussion: https://postgr.es/m/F2772387-CE0F-46BF-B5F1-CC55516EB885@amazon.com
This change refactors the shared memory size calculation in
CreateSharedMemoryAndSemaphores() to its own function. This is intended
for use in a future change related to the setup of huge pages and shared
memory with some GUCs, while useful on its own for extensions.
Author: Nathan Bossart
Discussion: https://postgr.es/m/F2772387-CE0F-46BF-B5F1-CC55516EB885@amazon.com
They are used in code that runs both during normal operation and during
WAL replay, and needs to behave differently during replay. Move them to
xlogutils.c, because that's where we have other helper functions used by
redo routines.
Reviewed-by: Andres Freund
Discussion: https://www.postgresql.org/message-id/b3b71061-4919-e882-4857-27e370ab134a%40iki.fi
The point of introducing the hash_mem_multiplier GUC was to let users
reproduce the old behavior of hash aggregation, i.e. that it could use
more than work_mem at need. However, the implementation failed to get
the job done on Win64, where work_mem is clamped to 2GB to protect
various places that calculate memory sizes using "long int". As
written, the same clamp was applied to hash_mem. This resulted in
severe performance regressions for queries requiring a bit more than
2GB for hash aggregation, as they now spill to disk and there's no
way to stop that.
Getting rid of the work_mem restriction seems like a good idea, but
it's a big job and could not conceivably be back-patched. However,
there's only a fairly small number of places that are concerned with
the hash_mem value, and it turns out to be possible to remove the
restriction there without too much code churn or any ABI breaks.
So, let's do that for now to fix the regression, and leave the
larger task for another day.
This patch does introduce a bit more infrastructure that should help
with the larger task, namely pg_bitutils.h support for working with
size_t values.
Per gripe from Laurent Hasson. Back-patch to v13 where the
behavior change came in.
Discussion: https://postgr.es/m/997817.1627074924@sss.pgh.pa.us
Discussion: https://postgr.es/m/MN2PR15MB25601E80A9B6D1BA6F592B1985E39@MN2PR15MB2560.namprd15.prod.outlook.com
5a1e1d8302 was a minimal bug fix for dc7420c2c9. To avoid future bugs of
that kind, deduplicate the choice of a relation's horizon into a new helper,
GlobalVisHorizonKindForRel().
As the code in question was only introduced in dc7420c2c9 it seems worth
backpatching this change as well, otherwise 14 will look different from all
other branches.
A different approach to this was suggested by Matthias van de Meent.
Author: Andres Freund
Discussion: https://postgr.es/m/20210621122919.2qhu3pfugxxp3cji@alap3.anarazel.de
Backpatch: 14, like 5a1e1d8302
Several places were performing a tight loop to determine the first power
of 2 number that's > or >= the required memory. Instead of using a loop
for that, we can use pg_nextpower2_32 or pg_nextpower2_64. When we need a
power of 2 number equal to or greater than a given amount, we just pass
the amount to the nextpower2 function. When we need a power of 2 greater
than the amount, we just pass the amount + 1.
Additionally, in tsearch there were a couple of locations that were
performing a while loop when a simple "if" would have done. In both of
these locations only 1 item is being added, so the loop could only have
ever iterated once. Changing the loop into an if statement makes the code
very slightly more optimal as the condition is checked once rather than
twice.
There are quite a few remaining locations that increase the size of the
buffer in the following form:
while (reqsize >= buflen)
{
buflen *= 2;
buf = repalloc(buf, buflen);
}
These are not touched in this commit. repalloc will error out for sizes
larger than MaxAllocSize. Changing these to use pg_nextpower2_32 would
remove the chance of that error being raised. It's unclear from the code
if the sizes could ever become that large, so err on the side of caution.
Discussion: https://postgr.es/m/CAApHDvp=tns7RL4PH0ZR0M+M-YFLquK7218x=0B_zO+DbOma+w@mail.gmail.com
Reviewed-by: Zhihong Yu
In dc7420c2c9 I (Andres) accidentally used
RelationIsAccessibleInLogicalDecoding() as the sole condition to use the
non-shared catalog horizon in GetOldestNonRemovableTransactionId(). That is
incorrect, as RelationIsAccessibleInLogicalDecoding() checks whether wal_level
is logical.
The correct check, as done e.g. in GlobalVisTestFor(), is to check
IsCatalogRelation() and RelationIsAccessibleInLogicalDecoding().
The observed misbehavior of this bug was that there could be an endless loop
in lazy_scan_prune(), because the horizons used in heap_page_prune() and the
individual tuple liveliness checks did not match. Likely there are other
potential consequences as well.
A later commit will unify the determination which horizon has to be used, and
add additional assertions to make it easier to catch a bug like this.
Reported-By: Justin Pryzby <pryzby@telsasoft.com>
Diagnosed-By: Matthias van de Meent <boekewurm+postgres@gmail.com>
Author: Matthias van de Meent <boekewurm+postgres@gmail.com>
Discussion: https://postgr.es/m/CAEze2Wg32Y9+WJfw=aofkRx1ZRFt_Ev6bNPc4PSaz7PjSFtZgQ@mail.gmail.com
It was unable to wait on a backend that had already left the procarray.
Users tolerant of that limitation can poll pg_stat_activity. Other
users can employ the "timeout" argument of pg_terminate_backend().
Reviewed by Bharath Rupireddy.
Discussion: https://postgr.es/m/20210605013236.GA208701@rfd.leadboat.com
Revert the pg_description entry to its v13 form, since those messages
usually remain shorter and don't discuss individual parameters. No
catversion bump, since pg_description content does not impair backend
compatibility or application compatibility.
Justin Pryzby
Discussion: https://postgr.es/m/20210612182743.GY16435@telsasoft.com
941697c3c1 changed ProcArrayAdd()/Remove() substantially. As reported by
zhanyi, I missed that due to the introduction of the PGPROC->pgxactoff
ProcArrayRemove() does not need to search for the position in
procArray->pgprocnos anymore - that's pgxactoff. Remove the search loop.
The removal of the search loop reduces assertion coverage a bit - but we can
easily do better than before by adding assertions to other loops over
pgprocnos elements.
Also do a bit of cleanup, mostly by reducing line lengths by introducing local
helper variables and adding newlines.
Author: zhanyi <w@hidva.com>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/tencent_5624AA3B116B3D1C31CA9744@qq.com
Also "make reformat-dat-files".
The only change worthy of note is that pgindent messed up the formatting
of launcher.c's struct LogicalRepWorkerId, which led me to notice that
that struct wasn't used at all anymore, so I just took it out.
This set of commits has some bugs with known fixes, but at this late
stage in the release cycle it seems best to revert and resubmit next
time, along with some new automated test coverage for this whole area.
Commits reverted:
dc88460c: Doc: Review for "Optionally prefetch referenced data in recovery."
1d257577: Optionally prefetch referenced data in recovery.
f003d9f8: Add circular WAL decoding buffer.
323cbe7c: Remove read_page callback from XLogReader.
Remove the new GUC group WAL_RECOVERY recently added by a55a9847, as the
corresponding section of config.sgml is now reverted.
Discussion: https://postgr.es/m/CAOuzzgrn7iKnFRsB4MHp3UisEQAGgZMbk_ViTN4HV4-Ksq8zCg%40mail.gmail.com
Instead, put them in via a format placeholder. This reduces the
number of distinct translatable messages and also reduces the chances
of typos during translation. We already did this for the system call
arguments in a number of cases, so this is just the same thing taken a
bit further.
Discussion: https://www.postgresql.org/message-id/flat/92d6f545-5102-65d8-3c87-489f71ea0a37%40enterprisedb.com
Introduce a new GUC recovery_prefetch, disabled by default. When
enabled, look ahead in the WAL and try to initiate asynchronous reading
of referenced data blocks that are not yet cached in our buffer pool.
For now, this is done with posix_fadvise(), which has several caveats.
Better mechanisms will follow in later work on the I/O subsystem.
The GUC maintenance_io_concurrency is used to limit the number of
concurrent I/Os we allow ourselves to initiate, based on pessimistic
heuristics used to infer that I/Os have begun and completed.
The GUC wal_decode_buffer_size is used to limit the maximum distance we
are prepared to read ahead in the WAL to find uncached blocks.
Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> (parts)
Reviewed-by: Andres Freund <andres@anarazel.de> (parts)
Reviewed-by: Tomas Vondra <tomas.vondra@2ndquadrant.com> (parts)
Tested-by: Tomas Vondra <tomas.vondra@2ndquadrant.com>
Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com>
Tested-by: Dmitry Dolgov <9erthalion6@gmail.com>
Tested-by: Sait Talha Nisanci <Sait.Nisanci@microsoft.com>
Discussion: https://postgr.es/m/CA%2BhUKGJ4VJN8ttxScUFM8dOKX0BrBiboo5uz1cq%3DAovOddfHpA%40mail.gmail.com
This adds a function, pg_wait_for_backend_termination(), and a new
timeout argument to pg_terminate_backend(), which will wait for the
backend to actually terminate (with or without signaling it to do so
depending on which function is called). The default behaviour of
pg_terminate_backend() remains being timeout=0 which does not waiting.
For pg_wait_for_backend_termination() the default wait is 5 seconds.
Author: Bharath Rupireddy
Reviewed-By: Fujii Masao, David Johnston, Muhammad Usama,
Hou Zhijie, Magnus Hagander
Discussion: https://postgr.es/m/CALj2ACUBpunmyhYZw-kXCYs5NM+h6oG_7Df_Tn4mLmmUQifkqA@mail.gmail.com
Snapshot caching, introduced in 623a9ba79b, did not increment
xactCompletionCount during subtransaction abort. That could lead to an older
snapshot being reused. That is, at least as far as I can see, not a
correctness issue (for MVCC snapshots there's no difference between "in
progress" and "aborted"). The only difference between the old and new
snapshots would be a newer ->xmax.
While HeapTupleSatisfiesMVCC makes the same visibility determination, reusing
the old snapshot leads HeapTupleSatisfiesMVCC to not set
HEAP_XMIN_INVALID. Which subsequently causes the kill_prior_tuple optimization
to not kick in (via HeapTupleIsSurelyDead() returning false). The performance
effects of doing the same index-lookups over and over again is how the issue
was discovered...
Fix the issue by incrementing xactCompletionCount in
XidCacheRemoveRunningXids. It already acquires ProcArrayLock exclusively,
making that an easy proposition.
Add a test to ensure that kill_prior_tuple prevents index growth when it
involves aborted subtransaction of the current transaction.
Author: Andres Freund
Discussion: https://postgr.es/m/20210406043521.lopeo7bbigad3n6t@alap3.anarazel.de
Discussion: https://postgr.es/m/20210317055718.v6qs3ltzrformqoa%40alap3.anarazel.de
Commit 3e98c0bafb added pg_backend_memory_contexts view to display
the memory contexts of the backend process. However its target process
is limited to the backend that is accessing to the view. So this is
not so convenient when investigating the local memory bloat of other
backend process. To improve this situation, this commit adds
pg_log_backend_memory_contexts() function that requests to log
the memory contexts of the specified backend process.
This information can be also collected by calling
MemoryContextStats(TopMemoryContext) via a debugger. But
this technique cannot be used in some environments because no debugger
is available there. So, pg_log_backend_memory_contexts() allows us to
see the memory contexts of specified backend more easily.
Only superusers are allowed to request to log the memory contexts
because allowing any users to issue this request at an unbounded rate
would cause lots of log messages and which can lead to denial of service.
On receipt of the request, at the next CHECK_FOR_INTERRUPTS(),
the target backend logs its memory contexts at LOG_SERVER_ONLY level,
so that these memory contexts will appear in the server log but not
be sent to the client. It logs one message per memory context.
Because if it buffers all memory contexts into StringInfo to log them
as one message, which may require the buffer to be enlarged very much
and lead to OOM error since there can be a large number of memory
contexts in a backend.
When a backend process is consuming huge memory, logging all its
memory contexts might overrun available disk space. To prevent this,
now this patch limits the number of child contexts to log per parent
to 100. As with MemoryContextStats(), it supposes that practical cases
where the log gets long will typically be huge numbers of siblings
under the same parent context; while the additional debugging value
from seeing details about individual siblings beyond 100 will not be large.
There was another proposed patch to add the function to return
the memory contexts of specified backend as the result sets,
instead of logging them, in the discussion. However that patch is
not included in this commit because it had several issues to address.
Thanks to Tatsuhito Kasahara, Andres Freund, Tom Lane, Tomas Vondra,
Michael Paquier, Kyotaro Horiguchi and Zhihong Yu for the discussion.
Bump catalog version.
Author: Atsushi Torikoshi
Reviewed-by: Kyotaro Horiguchi, Zhihong Yu, Fujii Masao
Discussion: https://postgr.es/m/0271f440ac77f2a4180e0e56ebd944d1@oss.nttdata.com
Maxim Orlov reported that the shutdown of standby server could result in
the following assertion failure. The cause of this issue was that,
when the shutdown caused the startup process to exit, recovery-time
transaction tracking was not shut down even if it's already initialized,
and some locks the tracked transactions were holding could not be released.
At this situation, if other process was invoked and the PGPROC entry that
the startup process used was assigned to it, it found such unreleased locks
and caused the assertion failure, during the initialization of it.
TRAP: FailedAssertion("SHMQueueEmpty(&(MyProc->myProcLocks[i]))"
This commit fixes this issue by making the startup process shut down
transaction tracking and release all locks, at the exit of it.
Back-patch to all supported branches.
Reported-by: Maxim Orlov
Author: Fujii Masao
Reviewed-by: Maxim Orlov
Discussion: https://postgr.es/m/ad4ce692cc1d89a093b471ab1d969b0b@postgrespro.ru
This implements asynchronous execution, which runs multiple parts of a
non-parallel-aware Append concurrently rather than serially to improve
performance when possible. Currently, the only node type that can be
run concurrently is a ForeignScan that is an immediate child of such an
Append. In the case where such ForeignScans access data on different
remote servers, this would run those ForeignScans concurrently, and
overlap the remote operations to be performed simultaneously, so it'll
improve the performance especially when the operations involve
time-consuming ones such as remote join and remote aggregation.
We may extend this to other node types such as joins or aggregates over
ForeignScans in the future.
This also adds the support for postgres_fdw, which is enabled by the
table-level/server-level option "async_capable". The default is false.
Robert Haas, Kyotaro Horiguchi, Thomas Munro, and myself. This commit
is mostly based on the patch proposed by Robert Haas, but also uses
stuff from the patch proposed by Kyotaro Horiguchi and from the patch
proposed by Thomas Munro. Reviewed by Kyotaro Horiguchi, Konstantin
Knizhnik, Andrey Lepikhov, Movead Li, Thomas Munro, Justin Pryzby, and
others.
Discussion: https://postgr.es/m/CA%2BTgmoaXQEt4tZ03FtQhnzeDEMzBck%2BLrni0UWHVVgOTnA6C1w%40mail.gmail.com
Discussion: https://postgr.es/m/CA%2BhUKGLBRyu0rHrDCMC4%3DRn3252gogyp1SjOgG8SEKKZv%3DFwfQ%40mail.gmail.com
Discussion: https://postgr.es/m/20200228.170650.667613673625155850.horikyota.ntt%40gmail.com
This commit changes WAL archiver process so that it's treated as
an auxiliary process and can use shared memory. This is an infrastructure
patch required for upcoming shared-memory based stats collector patch
series. These patch series basically need any processes including archiver
that can report the statistics to access to shared memory. Since this patch
itself is useful to simplify the code and when users monitor the status of
archiver, it's committed separately in advance.
This commit simplifies the code for WAL archiving. For example, previously
backends need to signal to archiver via postmaster when they notify
archiver that there are some WAL files to archive. On the other hand,
this commit removes that signal to postmaster and enables backends to
notify archier directly using shared latch.
Also, as the side of this change, the information about archiver process
becomes viewable at pg_stat_activity view.
Author: Kyotaro Horiguchi
Reviewed-by: Andres Freund, Álvaro Herrera, Julien Rouhaud, Tomas Vondra, Arthur Zakirov, Fujii Masao
Discussion: https://postgr.es/m/20180629.173418.190173462.horiguchi.kyotaro@lab.ntt.co.jp
Cut down on system calls and other overheads by waiting for SIGURG
explicitly with kqueue instead of using a signal handler and self-pipe.
Affects *BSD and macOS systems.
This leaves only the poll implementation with a signal handler and the
traditional self-pipe trick.
Discussion: https://postgr.es/m/CA+hUKGJjxPDpzBE0a3hyUywBvaZuC89yx3jK9RFZgfv_KHU7gg@mail.gmail.com
