The checkpointer shouldn't ignore its latch. Other backends may be
waiting for it to drain the request queue. Hopefully real systems don't
have a full queue often, but the condition is reached easily when
shared_buffers is small.
This involves defining a new wait event, which will appear in the
pg_stat_activity view often due to spread checkpoints.
Back-patch only to 14. Even though the problem exists in earlier
branches too, it's hard to hit there. In 14 we stopped using signal
handlers for latches on Linux, *BSD and macOS, which were previously
hiding this problem by interrupting the sleep (though not reliably, as
the signal could arrive before the sleep begins; precisely the problem
latches address).
Reported-by: Andres Freund <andres@anarazel.de>
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20220226213942.nb7uvb2pamyu26dj%40alap3.anarazel.de
It was decided (refer to the Discussion link below) that the stats
collector is not an appropriate place to store the error information of
subscription workers.
This patch changes the pg_stat_subscription_workers view (introduced by
commit 8d74fc96db) so that it stores only statistics counters:
apply_error_count and sync_error_count, and has one entry for
each subscription. The removed error information such as error-XID and
the error message would be stored in another way in the future which is
more reliable and persistent.
After removing these error details, there is no longer any relation
information, so the subscription statistics are now a cluster-wide
statistics.
The patch also changes the view name to pg_stat_subscription_stats since
the word "worker" is an implementation detail that we use one worker for
one tablesync and one apply.
Author: Masahiko Sawada, based on suggestions by Andres Freund
Reviewed-by: Peter Smith, Haiying Tang, Takamichi Osumi, Amit Kapila
Discussion: https://postgr.es/m/20220125063131.4cmvsxbz2tdg6g65@alap3.anarazel.de
GCC 12 complains that set_stack_base is storing the address of
a local variable in a long-lived pointer. This is an entirely
reasonable warning (indeed, it just helped us find a bug);
but that behavior is intentional here. We can work around it
by using __builtin_frame_address(0) instead of a specific local
variable; that produces an address a dozen or so bytes different,
in my testing, but we don't care about such a small difference.
Maybe someday a compiler lacking that function will start to issue
a similar warning, but we'll worry about that when it happens.
Patch by me, per a suggestion from Andres Freund. Back-patch to
v12, which is as far back as the patch will go without some pain.
(Recently-established project policy would permit a back-patch as
far as 9.2, but I'm disinclined to expend the work until GCC 12
is much more widespread.)
Discussion: https://postgr.es/m/3773792.1645141467@sss.pgh.pa.us
This moves the functions related to performing WAL recovery into the new
xlogrecovery.c source file, leaving xlog.c responsible for maintaining
the WAL buffers, coordinating the startup and switch from recovery to
normal operations, and other miscellaneous stuff that have always been in
xlog.c.
Reviewed-by: Andres Freund, Kyotaro Horiguchi, Robert Haas
Discussion: https://www.postgresql.org/message-id/a31f27b4-a31d-f976-6217-2b03be646ffa%40iki.fi
The AF_UNIX macro was being used unprotected by HAVE_UNIX_SOCKETS,
apparently since 2008. So the redirection through IS_AF_UNIX() is
apparently no longer necessary. (More generally, all supported
platforms are now HAVE_UNIX_SOCKETS, but even if there were a new
platform in the future, it seems plausible that it would define the
AF_UNIX symbol even without kernel support.) So remove the
IS_AF_UNIX() macro and make the code a bit more consistent.
Discussion: https://www.postgresql.org/message-id/flat/f2d26815-9832-e333-d52d-72fbc0ade896%40enterprisedb.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
Running a shell command for each file to be archived has a lot of
overhead and may not offer as much error checking as you want, or the
exact semantics that you want. So, offer the option to call a loadable
module for each file to be archived, rather than running a shell command.
Also, add a 'basic_archive' contrib module as an example implementation
that archives to a local directory.
Nathan Bossart, with a little bit of kibitzing by me.
Discussion: http://postgr.es/m/20220202224433.GA1036711@nathanxps13
Since 6bc8ef0b, InitializeMaxBackends() has used max_worker_processes
instead of adapting MaxBackends to the number of background workers
registered by modules loaded in shared_preload_libraries (at this time,
bgworkers were only static, but gained dynamic capabilities as a matter
of supporting parallel queries meaning that a control cap was
necessary).
Some comments referred to the past registration logic, making them
confusing and incorrect, so fix these.
Some of the out-of-core modules that could be loaded in this path
sometimes like to manipulate dynamically some of the resource-related
GUCs for their own needs, this commit adds a note about that.
Author: Nathan Bossart
Discussion: https://postgr.es/m/20220127181815.GA551692@nathanxps13
"jsonlog" is a new value that can be added to log_destination to provide
logs in the JSON format, with its output written to a file, making it
the third type of destination of this kind, after "stderr" and
"csvlog". The format is convenient to feed logs to other applications.
There is also a plugin external to core that provided this feature using
the hook in elog.c, but this had to overwrite the output of "stderr" to
work, so being able to do both at the same time was not possible. The
files generated by this log format are suffixed with ".json", and use
the same rotation policies as the other two formats depending on the
backend configuration.
This takes advantage of the refactoring work done previously in ac7c807,
bed6ed3, 8b76f89 and 2d77d83 for the backend parts, and 72b76f7 for the
TAP tests, making the addition of any new file-based format rather
straight-forward.
The documentation is updated to list all the keys and the values that
can exist in this new format. pg_current_logfile() also required a
refresh for the new option.
Author: Sehrope Sarkuni, Michael Paquier
Reviewed-by: Nathan Bossart, Justin Pryzby
Discussion: https://postgr.es/m/CAH7T-aqswBM6JWe4pDehi1uOiufqe06DJWaU5=X7dDLyqUExHg@mail.gmail.com
Previously pg_log_backend_memory_contexts() could request to
log the memory contexts of backends, but not of auxiliary processes
such as checkpointer. This commit enhances the function so that
it can also send the request to auxiliary processes. It's useful to
look at the memory contexts of those processes for debugging purpose
and better understanding of the memory usage pattern of them.
Note that pg_log_backend_memory_contexts() cannot send the request
to logger or statistics collector. Because this logging request
mechanism is based on shared memory but those processes aren't
connected to that.
Author: Bharath Rupireddy
Reviewed-by: Vignesh C, Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/CALj2ACU1nBzpacOK2q=a65S_4+Oaz_rLTsU1Ri0gf7YUmnmhfQ@mail.gmail.com
The arch_filenames[] array elements were one byte too small, so that
a maximum-length filename would get corrupted if another entry
were made after it. (Noted by Thomas Munro, fix by Nathan Bossart.)
Move these arrays into a palloc'd struct, so that we aren't wasting
a few kilobytes of static data in each non-archiver process.
Add a binaryheap_reset() call to make it plain that we start the
directory scan with an empty heap. I don't think there's any live
bug of that sort, but it seems fragile, and this is very cheap
insurance.
Cleanup for commit beb4e9ba1, so no back-patch needed.
Discussion: https://postgr.es/m/CA+hUKGLHAjHuKuwtzsW7uMJF4BVPcQRL-UMZG_HM-g0y7yLkUg@mail.gmail.com
It's not great that RecoveryInProgress() calls InitXLOGAccess(),
because a status inquiry function typically shouldn't have the side
effect of performing initializations. We could fix that by calling
InitXLOGAccess() from some other place, but instead, let's remove it
altogether.
One thing InitXLogAccess() did is initialize wal_segment_size, but it
doesn't need to do that. In the postmaster, PostmasterMain() calls
LocalProcessControlFile(), and all child processes will inherit that
value -- except in EXEC_BACKEND bulds, but then each backend runs
SubPostmasterMain() which also calls LocalProcessControlFile().
The other thing InitXLOGAccess() did is update RedoRecPtr and
doPageWrites, but that's not critical, because all code that uses
them will just retry if it turns out that they've changed. The
only difference is that most code will now see an initial value that
is definitely invalid instead of one that might have just been way
out of date, but that will only happen once per backend lifetime,
so it shouldn't be a big deal.
Patch by me, reviewed by Nathan Bossart, Michael Paquier, Andres
Freund, Heikki Linnakangas, and Álvaro Herrera.
Discussion: http://postgr.es/m/CA+TgmoY7b65qRjzHN_tWUk8B4sJqk1vj1d31uepVzmgPnZKeLg@mail.gmail.com
The idea here is that when a performance problem is known to have
occurred at a certain point in time, it's a good thing if there is
some information available from the logs to help figure out what
might have happened around that time.
This change attracted an above-average amount of dissent, because
it means that a server with default settings will produce some amount
of log output even if nothing has gone wrong. However, by my count,
the mailing list discussion had about twice as many people in favor
of the change as opposed. The reasons for believing that the extra
log output is not an issue in practice are: (1) the rate at which
messages can be generated by this setting is bounded to one every
few minutes on a properly-configured system and (2) production
systems tend to have a lot more junk in the log from that due to
failed connection attempts, ERROR messages generated by application
activity, and the like.
Bharath Rupireddy, reviewed by Fujii Masao and by me. Many other
people commented on the thread, but as far as I can see that was
discussion of the merits of the change rather than review of the
patch.
Discussion: https://postgr.es/m/CALj2ACX-rW_OeDcp4gqrFUAkf1f50Fnh138dmkd0JkvCNQRKGA@mail.gmail.com
This commit adds a new system view pg_stat_subscription_workers, that
shows information about any errors which occur during the application of
logical replication changes as well as during performing initial table
synchronization. The subscription statistics entries are removed when the
corresponding subscription is removed.
It also adds an SQL function pg_stat_reset_subscription_worker() to reset
single subscription errors.
The contents of this view can be used by an upcoming patch that skips the
particular transaction that conflicts with the existing data on the
subscriber.
This view can be extended in the future to track other xact related
statistics like the number of xacts committed/aborted for subscription
workers.
Author: Masahiko Sawada
Reviewed-by: Greg Nancarrow, Hou Zhijie, Tang Haiying, Vignesh C, Dilip Kumar, Takamichi Osumi, Amit Kapila
Discussion: https://postgr.es/m/CAD21AoDeScrsHhLyEPYqN3sydg6PxAPVBboK=30xJfUVihNZDA@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
A few strings (one WARNING and some memory context names) in the
autovacuum code were written in a world where "worker" had no other
possible meaning than "autovacuum worker", but that's long time gone.
Be more specific about it.
Also, change the WARNING from elog() to ereport(), to add translability.
Author: Bharath Rupireddy <bharath.rupireddyforpostgres@gmail.com>
Reviewed-by: Nathan Bossart <bossartn@amazon.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Dilip Kumar <dilipbalaut@gmail.com>
Reviewed-by: Masahiko Sawada <sawada.mshk@gmail.com>
Discussion: https://postgr.es/m/CALj2ACX2UHp76dqdoZq92a7v4APFuV5wJQ+AUrb+2HURrKN=NQ@mail.gmail.com
Presently, the archive_status directory was scanned for each file to
archive. When there are many status files, say because archive_command
has been failing for a long time, these directory scans can get very
slow. With this change, the archiver remembers several files to archive
during each directory scan, speeding things up.
To ensure timeline history files are archived as quickly as possible,
XLogArchiveNotify() forces the archiver to do a new directory scan as
soon as the .ready file for one is created.
Nathan Bossart, per a long discussion involving many people. It is
not clear to me exactly who out of all those people reviewed this
particular patch.
Discussion: http://postgr.es/m/CA+TgmobhAbs2yabTuTRkJTq_kkC80-+jw=pfpypdOJ7+gAbQbw@mail.gmail.com
Discussion: http://postgr.es/m/620F3CE1-0255-4D66-9D87-0EADE866985A@amazon.com
This check was used to accommodate a staggering variety in particular
in the type of the third argument of accept(). This is no longer of
concern on currently supported systems. We can just use socklen_t in
the code and put in a simple check that substitutes int for socklen_t
if it's missing, to cover the few stragglers.
Reviewed-by: Andres Freund <andres@anarazel.de>
Discussion: https://www.postgresql.org/message-id/3538f4c4-1886-64f2-dcff-aaad8267fb82@enterprisedb.com
The server collects up to a bufferload of data whenever it reads data
from the client socket. When SSL or GSS encryption is requested
during startup, any additional data received with the initial
request message remained in the buffer, and would be treated as
already-decrypted data once the encryption handshake completed.
Thus, a man-in-the-middle with the ability to inject data into the
TCP connection could stuff some cleartext data into the start of
a supposedly encryption-protected database session.
This could be abused to send faked SQL commands to the server,
although that would only work if the server did not demand any
authentication data. (However, a server relying on SSL certificate
authentication might well not do so.)
To fix, throw a protocol-violation error if the internal buffer
is not empty after the encryption handshake.
Our thanks to Jacob Champion for reporting this problem.
Security: CVE-2021-23214
Commit 9ce346eabf added startup
progress reporting, but begin_startup_progress_phase has a race
condition: the timeout for the previous phase might fire just
before we reschedule the interrupt for the next phase.
To avoid the race, disable the timeout, clear the flag, and then
re-enable the timeout.
Patch by me, reviewed by Nitin Jadhav.
Discussion: https://postgr.es/m/CA+TgmoYq38i6iAzfRLVxA6Cm+wMCf4WM8wC3o_a+X_JvWC8bJg@mail.gmail.com
Users sometimes get concerned whe they start the server and it
emits a few messages and then doesn't emit any more messages for
a long time. Generally, what's happening is either that the
system is taking a long time to apply WAL, or it's taking a
long time to reset unlogged relations, or it's taking a long
time to fsync the data directory, but it's not easy to tell
which is the case.
To fix that, add a new 'log_startup_progress_interval' setting,
by default 10s. When an operation that is known to be potentially
long-running takes more than this amount of time, we'll log a
status update each time this interval elapses.
To avoid undesirable log chatter, don't log anything about WAL
replay when in standby mode.
Nitin Jadhav and Robert Haas, reviewed by Amul Sul, Bharath
Rupireddy, Justin Pryzby, Michael Paquier, and Álvaro Herrera.
Discussion: https://postgr.es/m/CA+TgmoaHQrgDFOBwgY16XCoMtXxsrVGFB2jNCvb7-ubuEe1MGg@mail.gmail.com
Discussion: https://postgr.es/m/CAMm1aWaHF7VE69572_OLQ+MgpT5RUiUDgF1x5RrtkJBLdpRj3Q@mail.gmail.com
Previously when pg_log_backend_memory_contexts() sent the request to
the autovacuum launcher, it could take more than several seconds to
log its memory contexts. Because the function (HandleAutoVacLauncherInterrupts)
to process any new interrupts that autovacuum launcher received
didn't handle the request for logging of memory contexts. This commit changes
the function so that it handles the request, to make autovacuum launcher
more responsitve to pg_log_backend_memory_contexts().
Back-patch to v14 where pg_log_backend_memory_contexts() was added.
Author: Koyu Tanigawa
Reviewed-by: Bharath Rupireddy, Atsushi Torikoshi
Discussion: https://postgr.es/m/0aae3e074face409b35153451be5cc11@oss.nttdata.com
stderr and csvlog have been using duplicated code when it came to the
rotation of their file by size, age or if forced by a user request
(pg_ctl logrotate or the SQL function pg_rotate_logfile). The main
difference between both is that stderr requires its file to always be
opened, so as it is possible to have a redirection route if the logging
collector is not ready yet to do its work if alternate destinations are
enabled.
Also, if csvlog gets disabled, we need to close properly its meta-data
stored in the logging collector (last file name for current_logfiles and
fd currently open for business). Except for those points, the code is
the same in terms of error handling and if a file should be created or
just continued.
This change makes the code simpler overall, and it will help in the
introduction of more file-based log destinations. This refactoring is
similar to the work done in 5b0b699. Most of the duplication originates
from fd801f4.
Some of the TAP tests of pg_ctl check the case of a forced log rotation,
but this is somewhat limited as there is no coverage for
log_rotation_age or log_rotation_size (these may not be worth the extra
resources to run either), and no coverage for reload of log_destination
with different combinations of stderr and csvlog. I have tested all
those cases separately for this refactoring.
Author: Michael Paquier
Discussion: https://postgr.es/m/CAH7T-aqswBM6JWe4pDehi1uOiufqe06DJWaU5=X7dDLyqUExHg@mail.gmail.com
A forked logging collector in EXEC_BACKEND builds passes down file
descriptors (or HANDLEs in WIN32) through a command for files to be
reopened (for stderr and csvlog). Some of its logic was duplicated, and
this commit refactors the code with some wrapper routines for file
reopening after forking and fd grabbing when building the command for
the fork.
While on it, this simplifies a use of "long" in the code, introduced by
ab0ba6e to take care of a warning related to MinGW-W64 when mapping a
intptr_t to a printed value. "long" is 32-bit long on Windows, and
interoperability of Win32 and Win64 ensures that handles are always
32-bit significant, so we can just use "int" for the same result. This
also makes the new routines more symmetric.
This change makes easier the introduction of new log destinations in the
logging collector, and this is not the only piece of refactoring
planned. I have tested this change with EXEC_BACKEND on linux, macos,
and of course MSVC (both Win32 and Win64), but not MinGW so the
buildfarm may have something to say here.
Author: Sehrope Sarkuni, Michael Paquier
Discussion: https://postgr.es/m/CAH7T-aqswBM6JWe4pDehi1uOiufqe06DJWaU5=X7dDLyqUExHg@mail.gmail.com
The upcoming shared memory stats patch drops stats for dropped objects in a
transactional manner, rather than removing them later as part of vacuum. This
means that stats for DROP inside a transaction needs to handle aborted
(sub-)transactions similar to TRUNCATE: The stats up to the DROP should be
restored.
Rename the existing infrastructure in preparation.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210405092914.mmxqe7j56lsjfsej@alap3.anarazel.de
An upcoming patch will add additional work to these functions. To avoid the
functions getting too complicated / doing too many things at once, split out
sub-tasks into their own functions.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210405092914.mmxqe7j56lsjfsej@alap3.anarazel.de
It was harder than necessary to understand PostgresMain() because the code for
a normal backend was interspersed with single-user mode specific code. Split
most of the single-user mode code into its own function
PostgresSingleUserMain(), that does all the necessary setup for single-user
mode, and then hands off after that to PostgresMain().
There still is some single-user mode code in InitPostgres(), and it'd likely
be worth moving at least some of it out. But that's for later.
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
An upcoming patch splits single user mode into its own function. This makes
that easier. Split out for easier review / testing.
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
Session statistics, as introduced by 960869da08, had several shortcomings:
- an additional GetCurrentTimestamp() call that also impaired the accuracy of
the data collected
This can be avoided by passing the current timestamp we already have in
pgstat_report_stat().
- an additional statistics UDP packet sent every 500ms
This is solved by adding the new statistics to PgStat_MsgTabstat.
This is conceptually ugly, because session statistics are not
table statistics. But the struct already contains data unrelated
to tables, so there is not much damage done.
Connection and disconnection are reported in separate messages, which
reduces the number of additional messages to two messages per session and a
slight increase in PgStat_MsgTabstat size (but the same number of table
stats fit).
- Session time computation could overflow on systems where long is 32 bit.
Reported-By: Andres Freund <andres@anarazel.de>
Author: Andres Freund <andres@anarazel.de>
Author: Laurenz Albe <laurenz.albe@cybertec.at>
Discussion: https://postgr.es/m/20210801205501.nyxzxoelqoo4x2qc%40alap3.anarazel.de
Backpatch: 14-, where the feature was introduced.
Until now, the -C option of postgres was handled before a small subset
of GUCs computed at runtime are initialized, leading to incorrect
results as GUC machinery would fall back to default values for such
parameters.
For example, data_checksums could report "off" for a cluster as the
control file is not loaded yet. Or wal_segment_size would show a
segment size at 16MB even if initdb --wal-segsize used something else.
Worse, the command would fail to properly report the recently-introduced
shared_memory, that requires to load shared_preload_libraries as these
could ask for a chunk of shared memory.
Support for runtime GUCs comes with a limitation, as the operation is
now allowed on a running server. One notable reason for this is that
_PG_init() functions of loadable libraries are called before all
runtime-computed GUCs are initialized, and this is not guaranteed to be
safe to do on running servers. For the case of shared_memory_size,
where we want to know how much memory would be used without allocating
it, this limitation is fine. Another case where this will help is for
huge pages, with the introduction of a different GUC to evaluate the
amount of huge pages required for a server before starting it, without
having to allocate large chunks of memory.
This feature is controlled with a new GUC flag, and four parameters are
classified as runtime-computed as of this change:
- data_checksums
- shared_memory_size
- data_directory_mode
- wal_segment_size
Some TAP tests are added to provide some coverage here, using
data_checksums in the tests of pg_checksums.
Per discussion with Andres Freund, Justin Pryzby, Magnus Hagander and
more.
Author: Nathan Bossart
Discussion: https://postgr.es/m/F2772387-CE0F-46BF-B5F1-CC55516EB885@amazon.com
The previous protocol expected a set of matching characters to check if
a message sent was the last one or not, that changed depending on the
destination wanted:
- 't' and 'f' tracked the last message of a log sent to stderr.
- 'T' and 'F' tracked the last message of a log sent to csvlog.
This could be extended with more characters when introducing new
destinations, but using a bitmask is much more elegant. This commit
changes the protocol so as a bitmask is used in the header of a log
chunk message sent to the syslogger, with the following options
available for now:
- log_destination as stderr.
- log_destination as csvlog.
- if a message is the last chunk of a message.
Sehrope found this issue in a patch set to introduce JSON as an option
for log_destination, but his patch made the size of the protocol header
larger. This commit keeps the same size as the original, and adapts the
protocol as wanted.
Thanks also to Andrew Dunstan and Greg Stark for the discussion.
Author: Michael Paquier, Sehrope Sarkuni
Discussion: https://postgr.es/m/CAH7T-aqswBM6JWe4pDehi1uOiufqe06DJWaU5=X7dDLyqUExHg@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 commit allows pg_stat_reset_single_table_counters() to reset statistics
for a single relation shared across all databases in the cluster to zero.
Bump catalog version.
Author: B Sadhu Prasad Patro
Reviewed-by: Mahendra Singh Thalor, Himanshu Upadhyaya, Dilip Kumar, Fujii Masao
Discussion: https://postgr.es/m/CAFF0-CGy7EHeF=AqqkGMF85cySPQBgDcvNk73G2O0vL94O5U5A@mail.gmail.com
In the long-going saga for analyze on partitioned tables, one thing I
missed while reverting 0827e8af70 is the maintenance of analyze count
and last analyze time for partitioned tables. This is a mostly trivial
change that enables users assess the need for invoking manual ANALYZE on
partitioned tables.
This patch, posted by Justin and modified a bit by me (Álvaro), can be
mostly traced back to Hosoya-san, though any problems introduced with
the scissors are mine.
Backpatch to 14, in line with 6f8127b739.
Co-authored-by: Yuzuko Hosoya <yuzukohosoya@gmail.com>
Co-authored-by: Justin Pryzby <pryzby@telsasoft.com>
Co-authored-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reported-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20210816222810.GE10479@telsasoft.com
WAL records may span multiple segments, but XLogWrite() does not
wait for the entire record to be written out to disk before
creating archive status files. Instead, as soon as the last WAL page of
the segment is written, the archive status file is created, and the
archiver may process it. If PostgreSQL crashes before it is able to
write and flush the rest of the record (in the next WAL segment), the
wrong version of the first segment file lingers in the archive, which
causes operations such as point-in-time restores to fail.
To fix this, keep track of records that span across segments and ensure
that segments are only marked ready-for-archival once such records have
been completely written to disk.
This has always been wrong, so backpatch all the way back.
Author: Nathan Bossart <bossartn@amazon.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Ryo Matsumura <matsumura.ryo@fujitsu.com>
Reviewed-by: Andrey Borodin <x4mmm@yandex-team.ru>
Discussion: https://postgr.es/m/CBDDFA01-6E40-46BB-9F98-9340F4379505@amazon.com
This reverts the following commits:
1b5617eb84 Describe (auto-)analyze behavior for partitioned tables
0e69f705cc Set pg_class.reltuples for partitioned tables
41badeaba8 Document ANALYZE storage parameters for partitioned tables
0827e8af70 autovacuum: handle analyze for partitioned tables
There are efficiency issues in this code when handling databases with
large numbers of partitions, and it doesn't look like there isn't any
trivial way to handle those. There are some other issues as well. It's
now too late in the cycle for nontrivial fixes, so we'll have to let
Postgres 14 users continue to manually deal with ANALYZE their
partitioned tables, and hopefully we can fix the issues for Postgres 15.
I kept [most of] be280cdad2 ("Don't reset relhasindex for partitioned
tables on ANALYZE") because while we added it due to 0827e8af70, it is
a good bugfix in its own right, since it affects manual analyze as well
as autovacuum-induced analyze, and there's no reason to revert it.
I retained the addition of relkind 'p' to tables included by
pg_stat_user_tables, because reverting that would require a catversion
bump.
Also, in pg14 only, I keep a struct member that was added to
PgStat_TabStatEntry to avoid breaking compatibility with existing stat
files.
Backpatch to 14.
Discussion: https://postgr.es/m/20210722205458.f2bug3z6qzxzpx2s@alap3.anarazel.de
Background workers without shared memory access have been broken on
EXEC_BACKEND / windows builds since shortly after background workers have been
introduced, without that being reported. Clearly they are not commonly used.
The problem is that bgworker startup requires to be attached to shared memory
in EXEC_BACKEND child processes. StartBackgroundWorker() detaches from shared
memory for unconnected workers, but at that point we already have initialized
subsystems referencing shared memory.
Fixing this problem is not entirely trivial, so removing the option to not be
connected to shared memory seems the best way forward. In most use cases the
advantages of being connected to shared memory far outweigh the disadvantages.
As there have been no reports about this issue so far, we have decided that it
is not worth trying to address the problem in the back branches.
Per discussion with Alvaro Herrera, Robert Haas and Tom Lane.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210802065116.j763tz3vz4egqy3w@alap3.anarazel.de
Previously pgstat_initialize() was called in InitPostgres() and
AuxiliaryProcessMain(). As it turns out there was at least one case where we
reported stats before pgstat_initialize() was called, see
AutoVacWorkerMain()'s intentionally early call to pgstat_report_autovac().
This turns out to not be a problem with the current pgstat implementation as
pgstat_initialize() only registers a shutdown callback. But in the shared
memory based stats implementation we are working towards pgstat_initialize()
has to do more work.
After b406478b87 BaseInit() is a central place where initialization shared by
normal backends and auxiliary backends can be put. Obviously BaseInit() is
called before InitPostgres() registers ShutdownPostgres. Previously
ShutdownPostgres was the first before_shmem_exit callback, now that's commonly
pgstats. That should be fine.
Previously pgstat_initialize() was not called in bootstrap mode, but there
does not appear to be a need for that. It's now done unconditionally.
To detect future issues like this, assertions are added to a few places
verifying that the pgstat subsystem is initialized and not yet shut down.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210405092914.mmxqe7j56lsjfsej@alap3.anarazel.de
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
For EXEC_BACKEND InitProcess()/InitAuxiliaryProcess() needs to have been
called well before we call BaseInit(), as SubPostmasterMain() needs LWLocks to
work. Having the order of initialization differ between platforms makes it
unnecessarily hard to understand the system and to add initialization points
for new subsystems without a lot of duplication.
To be able to change the order, BaseInit() cannot trigger
CreateSharedMemoryAndSemaphores() anymore - obviously that needs to have
happened before we can call InitProcess(). It seems cleaner to create shared
memory explicitly in single user/bootstrap mode anyway.
After this change the separation of bufmgr initialization into
InitBufferPoolAccess() / InitBufferPoolBackend() is not meaningful anymore so
the latter is removed.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
This was an oversight in 07bf378509. While it does reduce the benefit of the
simplification due to that commit, it still seems like a win to me.
It seems like it might be a good idea to have a function mirroring
InitPostmasterChild() / InitStandaloneProcess() for postmaster in miscinit.c
to make it easier to keep initialization between the three possible
environment in sync.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210805214109.lzfk3r3ae37bahmv@alap3.anarazel.de
For one, the existing location lead to somewhat awkward code in main(). For
another, the new location is easier to understand anyway.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
Neither is actually initialized as an auxiliary process, so it does not really
make sense to reserve a PGPROC etc for them.
This keeps checker mode implemented by exiting partway through bootstrap
mode. That might be worth changing at some point, perhaps if we ever extend
checker mode to be a more general tool.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
After the preceding commits the auxprocess code is independent from
bootstrap.c - so a dedicated file seems less confusing.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
There practically was no shared code between the two, once all the ifs are
removed. And it was quite confusing that aux processes weren't actually
started by the call to AuxiliaryProcessMain() in main().
There's more to do, AuxiliaryProcessMain() should move out of bootstrap.c, and
BootstrapModeMain() shouldn't use/be part of AuxProcType.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
It is confusing that aux processes are started with --forkboot, given that
bootstrap mode cannot run below postmaster.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210802164124.ufo5buo4apl6yuvs@alap3.anarazel.de
These have been unrelated since bgwriter and checkpointer were split into two
processes in 806a2aee37. As there several pending patches (shared memory
stats, extending the set of tracked IO / buffer statistics) that are made a
bit more awkward by the grouping, split them. Done separately to make
reviewing easier.
This does *not* change the contents of pg_stat_bgwriter or move fields out of
bgwriter/checkpointer stats that arguably do not belong in either. However
pgstat_fetch_global() was renamed and split into
pgstat_fetch_stat_checkpointer() and pgstat_fetch_stat_bgwriter().
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210405092914.mmxqe7j56lsjfsej@alap3.anarazel.de
Start up the checkpointer and bgwriter during crash recovery (except in
--single mode), as we do for replication. This wasn't done back in
commit cdd46c76 out of caution. Now it seems like a better idea to make
the environment as similar as possible in both cases. There may also be
some performance advantages.
Reviewed-by: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Aleksander Alekseev <aleksander@timescale.com>
Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com>
Discussion: https://postgr.es/m/CA%2BhUKGJ8NRsqgkZEnsnRc2MFROBV-jCnacbYvtpptK2A9YYp9Q%40mail.gmail.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
Generalize the INDEX_CLEANUP VACUUM parameter (and the corresponding
reloption): make it into a ternary style boolean parameter. It now
exposes a third option, "auto". The "auto" option (which is now the
default) enables the "bypass index vacuuming" optimization added by
commit 1e55e7d1.
"VACUUM (INDEX_CLEANUP TRUE)" is redefined to once again make VACUUM
simply do any required index vacuuming, regardless of how few dead
tuples are encountered during the first scan of the target heap relation
(unless there are exactly zero). This gives users a way of opting out
of the "bypass index vacuuming" optimization, if for whatever reason
that proves necessary. It is also expected to be used by PostgreSQL
developers as a testing option from time to time.
"VACUUM (INDEX_CLEANUP FALSE)" does the same thing as it always has: it
forcibly disables both index vacuuming and index cleanup. It's not
expected to be used much in PostgreSQL 14. The failsafe mechanism added
by commit 1e55e7d1 addresses the same problem in a simpler way.
INDEX_CLEANUP can now be thought of as a testing and compatibility
option.
Author: Peter Geoghegan <pg@bowt.ie>
Reviewed-By: Masahiko Sawada <sawada.mshk@gmail.com>
Reviewed-By: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/CAH2-WznrBoCST4_Gxh_G9hA8NzGUbeBGnOUC8FcXcrhqsv6OHQ@mail.gmail.com
Emit a LOG message when the postmaster stops because of a failure in
the startup process. There already is a similar message if we exit
for that reason during PM_STARTUP phase, so it seems inconsistent
that there was none if the startup process fails later on.
Also emit a LOG message when the postmaster stops after a crash
because restart_after_crash is disabled. This seems potentially
helpful in case DBAs (or developers) forget that that's set.
Also, it was the only remaining place where the postmaster would
do an abnormal exit without any comment as to why.
In passing, remove an unreachable call of ExitPostmaster(0).
Discussion: https://postgr.es/m/194914.1621641288@sss.pgh.pa.us
1) Previously there were both pgstat_send_wal() and pgstat_report_wal()
in order to send WAL activity to the stats collector. With the former being
used by wal writer, the latter by most other processes. They were a bit
redundant and so this commit merges them into pgstat_send_wal() to
simplify the code.
2) Previously WAL global statistics counters were calculated and then
compared with zero-filled buffer in order to determine whether any WAL
activity has happened since the last submission. These calculation and
comparison were not cheap. This was regularly exercised even in read-only
workloads. This commit fixes the issue by making some WAL activity
counters directly be checked to determine if there's WAL activity stats
to send.
3) Previously pgstat_report_stat() did not check if there's WAL activity
stats to send as part of the "Don't expend a clock check if nothing to do"
check at the top. It's probably rare to have pending WAL stats without
also passing one of the other conditions, but for safely this commit
changes pgstat_report_stats() so that it checks also some WAL activity
counters at the top.
This commit also adds the comments about the design of WAL stats.
Reported-by: Andres Freund
Author: Masahiro Ikeda
Reviewed-by: Kyotaro Horiguchi, Atsushi Torikoshi, Andres Freund, Fujii Masao
Discussion: https://postgr.es/m/20210324232224.vrfiij2rxxwqqjjb@alap3.anarazel.de
Allowing only on/off meant that all either all existing configuration
guides would become obsolete if we disabled it by default, or that we
would have to accept a performance loss in the default config if we
enabled it by default. By allowing 'auto' as a middle ground, the
performance cost is only paid by those who enable pg_stat_statements and
similar modules.
I only edited the release notes to comment-out a paragraph that is now
factually wrong; further edits are probably needed to describe the
related change in more detail.
Author: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Justin Pryzby <pryzby@telsasoft.com>
Discussion: https://postgr.es/m/20210513002623.eugftm4nk2lvvks3@nol
ForgetBackgroundWorker lacked any memory barrier at all, while
BackgroundWorkerStateChange had one but unaccountably did
additional manipulation of the slot after the barrier. AFAICS,
the rule must be that the barrier is immediately before setting
or clearing slot->in_use.
It looks like back in 9.6 when ForgetBackgroundWorker was first
written, there might have been some case for not needing a
barrier there, but I'm not very convinced of that --- the fact
that the load of bgw_notify_pid is in the caller doesn't seem
to guarantee no memory ordering problem. So patch 9.6 too.
It's likely that this doesn't fix any observable bug on Intel
hardware, but machines with weaker memory ordering rules could
have problems here.
Discussion: https://postgr.es/m/4046084.1620244003@sss.pgh.pa.us
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
Previously, we used to use the array of size max_replication_slots to
store stats for replication slots. But that had two problems in the cases
where a message for dropping a slot gets lost: 1) the stats for the new
slot are not recorded if the array is full and 2) writing beyond the end
of the array if the user reduces the max_replication_slots.
This commit uses HTAB for replication slot statistics, resolving both
problems. Now, pgstat_vacuum_stat() search for all the dead replication
slots in stats hashtable and tell the collector to remove them. To avoid
showing the stats for the already-dropped slots, pg_stat_replication_slots
view searches slot stats by the slot name taken from pg_replication_slots.
Also, we send a message for creating a slot at slot creation, initializing
the stats. This reduces the possibility that the stats are accumulated
into the old slot stats when a message for dropping a slot gets lost.
Reported-by: Andres Freund
Author: Sawada Masahiko, test case by Vignesh C
Reviewed-by: Amit Kapila, Vignesh C, Dilip Kumar
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
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
Add a few words of comment to explain why SIGURG doesn't follow the
dummy_handler pattern used for SIGUSR2, since that might otherwise
appear to be a bug.
Discussion: https://postgr.es/m/4006115.1618577212%40sss.pgh.pa.us
This adds the statistics about total transactions count and total
transaction data logically sent to the decoding output plugin from
ReorderBuffer. Users can query the pg_stat_replication_slots view to check
these stats.
Suggested-by: Andres Freund
Author: Vignesh C and Amit Kapila
Reviewed-by: Sawada Masahiko, Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
This will make it consistent with the other usage of slotname in the code.
In the passing, change pgstat_report_replslot signature to use a structure
rather than multiple parameters.
Reported-by: Andres Freund
Author: Vignesh C
Reviewed-by: Sawada Masahiko, Amit Kapila
Discussion: https://postgr.es/m/20210319185247.ldebgpdaxsowiflw@alap3.anarazel.de
When commit 0827e8af70 added auto-analyze support for partitioned
tables, it included code to obtain reltuples for the partitioned table
as a number of catalog accesses to read pg_class.reltuples for each
partition. That's not only very inefficient, but also problematic
because autovacuum doesn't hold any locks on any of those tables -- and
doesn't want to. Replace that code with a read of pg_class.reltuples
for the partitioned table, and make sure ANALYZE and TRUNCATE properly
maintain that value.
I found no code that would be affected by the change of relpages from
zero to non-zero for partitioned tables, and no other code that should
be maintaining it, but if there is, hopefully it'll be an easy fix.
Per buildfarm.
Author: Álvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Zhihong Yu <zyu@yugabyte.com>
Discussion: https://postgr.es/m/1823909.1617862590@sss.pgh.pa.us
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
Previously, autovacuum would completely ignore partitioned tables, which
is not good regarding analyze -- failing to analyze those tables means
poor plans may be chosen. Make autovacuum aware of those tables by
propagating "changes since analyze" counts from the leaf partitions up
the partitioning hierarchy.
This also introduces necessary reloptions support for partitioned tables
(autovacuum_enabled, autovacuum_analyze_scale_factor,
autovacuum_analyze_threshold). It's unclear how best to document this
aspect.
Author: Yuzuko Hosoya <yuzukohosoya@gmail.com>
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Reviewed-by: Tomas Vondra <tomas.vondra@enterprisedb.com>
Reviewed-by: Álvaro Herrera <alvherre@alvh.no-ip.org>
Discussion: https://postgr.es/m/CAKkQ508_PwVgwJyBY=0Lmkz90j8CmWNPUxgHvCUwGhMrouz6UA@mail.gmail.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
Backend status (supporting pg_stat_activity) and command
progress (supporting pg_stat_progress*) related code is largely
independent from the rest of pgstat.[ch] (supporting views like
pg_stat_all_tables that accumulate data over time). See also
a333476b92.
This commit doesn't rename the function names to make the distinction
from the rest of pgstat_ clearer - that'd be more invasive and not
clearly beneficial. If we were to decide to do such a rename at some
point, it's better done separately from moving the code as well.
Robert's review was of an earlier version.
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210316195440.twxmlov24rr2nxrg@alap3.anarazel.de
The wait event related code is independent from the rest of the
pgstat.[ch] code, of nontrivial size and changes on a regular
basis. Put it into its own set of files.
As there doesn't seem to be a good pre-existing directory for code
like this, add src/backend/utils/activity.
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Discussion: https://postgr.es/m/20210316195440.twxmlov24rr2nxrg@alap3.anarazel.de
The caller of pgstat_report_replslot() passes int64 values to the function.
Also the function stores those values in PgStat_Counter (i.e., int64) fields
of PgStat_MsgReplSlot struct. But previously the function used "int" as
the data types of some arguments for those values, which could lead to
the overflow of values.
To avoid this risk, this commit fixes pgstat_report_replslot() to use
PgStat_Counter type for the arguments. Since they are the statistics counters,
PgStat_Counter, the data type used for counters, is used for them
instead of int64.
Reported-by: Vignesh C
Author: Vignesh C
Reviewed-by: Jeevan Ladhe, Fujii Masao
Discussion: https://postgr.es/m/CALDaNm080OpG=ZwOb0i8EyChH5SyHAMFWJCKaKTXmrfvJLbgaA@mail.gmail.com
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
Previously when an archive recovery or a standby was starting and
reached the consistent recovery state but hot_standby was configured
to off, the error message when a client connectted was "the database
system is starting up", which was needless confusing and not really
all that accurate either.
This commit improves the connection denied error message during
recovery, as follows, so that the users immediately know that their
servers are configured to deny those connections.
- If hot_standby is disabled, the error message "the database system
is not accepting connections" and the detail message "Hot standby
mode is disabled." are output when clients connect while an archive
recovery or a standby is running.
- If hot_standby is enabled, the error message "the database system
is not yet accepting connections" and the detail message
"Consistent recovery state has not been yet reached." are output
when clients connect until the consistent recovery state is reached
and postmaster starts accepting read only connections.
This commit doesn't change the connection denied error message of
"the database system is starting up" during normal server startup and
crash recovery. Because it's still suitable for those situations.
Author: James Coleman
Reviewed-by: Alvaro Herrera, Andres Freund, David Zhang, Tom Lane, Fujii Masao
Discussion: https://postgr.es/m/CAAaqYe8h5ES_B=F_zDT+Nj9XU7YEwNhKhHA2RE4CFhAQ93hfig@mail.gmail.com
Common recommendations are that the checkpoint should be spread out as
much as possible, provided we avoid having it take too long. This
change updates the default to 0.9 (from 0.5) to match that
recommendation.
There was some debate about possibly removing the option entirely but it
seems there may be some corner-cases where having it set much lower to
try to force the checkpoint to be as fast as possible could result in
fewer periods of time of reduced performance due to kernel flushing.
General agreement is that the "spread more" is the preferred approach
though and those who need to tune away from that value are much less
common.
Reviewed-By: Michael Paquier, Peter Eisentraut, Tom Lane, David Steele,
Nathan Bossart
Discussion: https://postgr.es/m/20201207175329.GM16415%40tamriel.snowman.net
Commit de829ddf23 added wait event WalrcvExit. But its name is not
consistent with other wait events like WalReceiverMain or
WalReceiverWaitStart, etc. So this commit renames WalrcvExit to
WalReceiverExit.
Author: Fujii Masao
Reviewed-by: Thomas Munro
Discussion: https://postgr.es/m/cced9995-8fa2-7b22-9d91-3f22a2b8c23c@oss.nttdata.com
Previously the type of this wait event was Client. But while this
wait event is being reported, walreceiver process is waiting for
the startup process to set initial data for streaming replication.
It's not waiting for any activity on a socket connected to a user
application or walsender. So this commit changes the type for
WalReceiverWaitStart wait event to IPC.
Author: Fujii Masao
Reviewed-by: Kyotaro Horiguchi
Discussion: https://postgr.es/m/cdacc27c-37ff-f1a4-20e2-ce19933abfcc@oss.nttdata.com
Commit 86c23a6eb2 changed the option to specify that postgres will
stop all other server processes by sending the signal SIGSTOP,
from -s to -T. But previously there were comments incorrectly
explaining that SIGSTOP behavior is set by -s option. This commit
fixes them.
Author: Kyotaro Horiguchi
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/20210316.165141.1400441966284654043.horikyota.ntt@gmail.com
After a crash of a backend using temporary files, the files used to be
left behind, on the basis that it might be useful for debugging. But we
don't have any reports of anyone actually doing that, and it means the
disk usage may grow over time due to repeated backend failures (possibly
even hitting ENOSPC). So this behavior is a bit unfortunate, and fixing
it required either manual cleanup (deleting files, which is error-prone)
or restart of the instance (i.e. service disruption).
This implements automatic cleanup of temporary files, controled by a new
GUC remove_temp_files_after_crash. By default the files are removed, but
it can be disabled to restore the old behavior if needed.
Author: Euler Taveira
Reviewed-by: Tomas Vondra, Michael Paquier, Anastasia Lubennikova, Thomas Munro
Discussion: https://postgr.es/m/CAH503wDKdYzyq7U-QJqGn%3DGm6XmoK%2B6_6xTJ-Yn5WSvoHLY1Ww%40mail.gmail.com
When accessing replication slot stats, introduced in 9868167500,
pgstat_read_statsfiles() reads the data into newly allocated
memory. Unfortunately the current memory context at that point is the
callers, leading to leaks and use-after-free dangers.
The fix is trivial, explicitly use pgStatLocalContext. There's some
potential for further improvements, but that's outside of the scope of
this bugfix.
No backpatch necessary, feature is only in HEAD.
Author: Andres Freund <andres@anarazel.de>
Discussion: https://postgr.es/m/20210317230447.c7uc4g3vbs4wi32i@alap3.anarazel.de
Commit 3048898e dropped -ING from some wait event names that correspond
to barrier phases. Update the phases' names to match.
While we're here making cosmetic changes, also rename "DONE" to "FREE".
That pairs better with "ALLOCATE", and describes the activity that
actually happens in that phase (as we do for the other phases) rather
than describing a state. The distinction is clearer after bugfix commit
3b8981b6 split the phase into two. As for the growth barriers, rename
their "ALLOCATE" phase to "REALLOCATE", which is probably a better
description of what happens then. Also improve the comments about
the phases a bit.
Discussion: https://postgr.es/m/CA%2BhUKG%2BMDpwF2Eo2LAvzd%3DpOh81wUTsrwU1uAwR-v6OGBB6%2B7g%40mail.gmail.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
Since commits 9f095299 and f98b8476 we don't poll the postmaster
pipe at all during crash recovery on Linux and FreeBSD, but on other
operating systems we were still doing it for every WAL record. Do it
less frequently on operating systems where system calls are required, at
the cost of delaying exit a bit after postmaster death. This avoids
expensive system calls reported to slow down CPU-bound recovery by as
much as 10-30%.
Reviewed-by: Heikki Linnakangas <hlinnaka@iki.fi>
Reviewed-by: Fujii Masao <masao.fujii@oss.nttdata.com>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Discussion: https://postgr.es/m/CA%2BhUKGK1607VmtrDUHQXrsooU%3Dap4g4R2yaoByWOOA3m8xevUQ%40mail.gmail.com
Discussion: https://postgr.es/m/7261eb39-0369-f2f4-1bb5-62f3b6083b5e@iki.fi
When shutdown is requested, checkpointer performs checkpoint or
restartpoint, and updates the statistics, before it exits. But previously
checkpointer didn't send those statistics to the stats collector.
Shutdown checkpoint and restartpoint are treated as requested ones
instead of scheduled ones, so the number of them are counted in
pg_stat_bgwriter.checkpoints_req column.
Author: Masahiro Ikeda
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
In walwriter's main loop, WAL stats message is only sent if enough time
has passed since last one was sent to reach PGSTAT_STAT_INTERVAL msecs.
This is necessary to avoid overloading to the stats collector. But this
can cause recent WAL stats to be unsent when walwriter exits.
To ensure that all the WAL stats are sent, this commit makes walwriter
force to send remaining WAL stats to the collector when it exits because
of shutdown request. Note that those remaining WAL stats can still be
unsent when walwriter exits with non-zero exit code (e.g., FATAL error).
This is OK because that walwriter exit leads to server crash and
subsequent recovery discards all the stats. So there is no need to send
remaining stats in that case.
Author: Masahiro Ikeda
Reviewed-by: Fujii Masao
Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
1. Backends waiting for buffer I/O are now interruptible.
2. If something goes wrong in a backend that is currently performing
I/O, waiting backends no longer wake up until that backend reaches
AbortBufferIO() and broadcasts on the CV. Previously, any waiters would
wake up (because the I/O lock was automatically released) and then
busy-loop until AbortBufferIO() cleared BM_IO_IN_PROGRESS.
3. LWLockMinimallyPadded is removed, as it would now be unused.
Author: Robert Haas <robertmhaas@gmail.com>
Reviewed-by: Thomas Munro <thomas.munro@gmail.com>
Reviewed-by: Julien Rouhaud <rjuju123@gmail.com>
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (earlier version, 2016)
Discussion: https://postgr.es/m/CA%2BhUKGJ8nBFrjLuCTuqKN0pd2PQOwj9b_jnsiGFFMDvUxahj_A%40mail.gmail.com
Discussion: https://postgr.es/m/CA+Tgmoaj2aPti0yho7FeEf2qt-JgQPRWb0gci_o1Hfr=C56Xng@mail.gmail.com
This commit adds new GUC track_wal_io_timing. When this is enabled,
the total amounts of time XLogWrite writes and issue_xlog_fsync syncs
WAL data to disk are counted in pg_stat_wal. This information would be
useful to check how much WAL write and sync affect the performance.
Enabling track_wal_io_timing will make the server query the operating
system for the current time every time WAL is written or synced,
which may cause significant overhead on some platforms. To avoid such
additional overhead in the server with track_io_timing enabled,
this commit introduces track_wal_io_timing as a separate parameter from
track_io_timing.
Note that WAL write and sync activity by walreceiver has not been tracked yet.
This commit makes the server also track the numbers of times XLogWrite
writes and issue_xlog_fsync syncs WAL data to disk, in pg_stat_wal,
regardless of the setting of track_wal_io_timing. This counters can be
used to calculate the WAL write and sync time per request, for example.
Bump PGSTAT_FILE_FORMAT_ID.
Bump catalog version.
Author: Masahiro Ikeda
Reviewed-By: Japin Li, Hayato Kuroda, Masahiko Sawada, David Johnston, Fujii Masao
Discussion: https://postgr.es/m/0509ad67b585a5b86a83d445dfa75392@oss.nttdata.com
PostgreSQL disabled compression as of e3bdb2d and the documentation
recommends against using it since. Additionally, SSL compression has
been disabled in OpenSSL since version 1.1.0, and was disabled in many
distributions long before that. The most recent TLS version, TLSv1.3,
disallows compression at the protocol level.
This commit removes the feature itself, removing support for the libpq
parameter sslcompression (parameter still listed for compatibility
reasons with existing connection strings, just ignored), and removes
the equivalent field in pg_stat_ssl and de facto PgBackendSSLStatus.
Note that, on top of removing the ability to activate compression by
configuration, compression is actively disabled in both frontend and
backend to avoid overrides from local configurations.
A TAP test is added for deprecated SSL parameters to check after
backwards compatibility.
Bump catalog version.
Author: Daniel Gustafsson
Reviewed-by: Peter Eisentraut, Magnus Hagander, Michael Paquier
Discussion: https://postgr.es/m/7E384D48-11C5-441B-9EC3-F7DB1F8518F6@yesql.se
Protocol version 3 was introduced in PostgreSQL 7.4. There shouldn't be
many clients or servers left out there without version 3 support. But as
a courtesy, I kept just enough of the old protocol support that we can
still send the "unsupported protocol version" error in v2 format, so that
old clients can display the message properly. Likewise, libpq still
understands v2 ErrorResponse messages when establishing a connection.
The impetus to do this now is that I'm working on a patch to COPY
FROM, to always prefetch some data. We cannot do that safely with the
old protocol, because it requires parsing the input one byte at a time
to detect the end-of-copy marker.
Reviewed-by: Tom Lane, Alvaro Herrera, John Naylor
Discussion: https://www.postgresql.org/message-id/9ec25819-0a8a-d51a-17dc-4150bb3cca3b%40iki.fi
Traditionally, SIGUSR1 has been overloaded for ad-hoc signals,
procsignal.c signals and latch.c wakeups. Move that last use over to a
new dedicated signal. SIGURG is normally used to report out-of-band
socket data, but PostgreSQL doesn't use that facility.
The signal handler is now installed in all postmaster children by
InitializeLatchSupport(). Those wishing to disconnect from it should
call ShutdownLatchSupport().
Future patches will use this separation of signals to avoid the need for
a signal handler on some operating systems.
Discussion: https://postgr.es/m/CA+hUKGJjxPDpzBE0a3hyUywBvaZuC89yx3jK9RFZgfv_KHU7gg@mail.gmail.com
This option controls if toast tables associated with a relation are
vacuumed or not when running a manual VACUUM. It was already possible
to trigger a manual VACUUM on a toast relation without processing its
main relation, but a manual vacuum on a main relation always forced a
vacuum on its toast table. This is useful in scenarios where the level
of bloat or transaction age of the main and toast relations differs a
lot.
This option is an extension of the existing VACOPT_SKIPTOAST that was
used by autovacuum to control if toast relations should be skipped or
not. This internal flag is renamed to VACOPT_PROCESS_TOAST for
consistency with the new option.
A new option switch, called --no-process-toast, is added to vacuumdb.
Author: Nathan Bossart
Reviewed-by: Kirk Jamison, Michael Paquier, Justin Pryzby
Discussion: https://postgr.es/m/BA8951E9-1524-48C5-94AF-73B1F0D7857F@amazon.com
This add counters for number of sessions, the different kind of session
termination types, and timers for how much time is spent in active vs
idle in a database to pg_stat_database.
Internally this also renames the parameter "force" to disconnect. This
was the only use-case for the parameter before, so repurposing it to
this mroe narrow usecase makes things cleaner than inventing something
new.
Author: Laurenz Albe
Reviewed-By: Magnus Hagander, Soumyadeep Chakraborty, Masahiro Ikeda
Discussion: https://postgr.es/m/b07e1f9953701b90c66ed368656f2aef40cac4fb.camel@cybertec.at
Unrecoverable errors detected by GSSAPI encryption can't just be
reported with elog(ERROR) or elog(FATAL), because attempting to
send the error report to the client is likely to lead to infinite
recursion or loss of protocol sync. Instead make this code do what
the SSL encryption code has long done, which is to just report any
such failure to the server log (with elevel COMMERROR), then pretend
we've lost the connection by returning errno = ECONNRESET.
Along the way, fix confusion about whether message translation is done
by pg_GSS_error() or its callers (the latter should do it), and make
the backend version of that function work more like the frontend
version.
Avoid allocating the port->gss struct until it's needed; we surely
don't need to allocate it in the postmaster.
Improve logging of "connection authorized" messages with GSS enabled.
(As part of this, I back-patched the code changes from dc11f31a1.)
Make BackendStatusShmemSize() account for the GSS-related space that
will be allocated by CreateSharedBackendStatus(). This omission
could possibly cause out-of-shared-memory problems with very high
max_connections settings.
Remove arbitrary, pointless restriction that only GSS authentication
can be used on a GSS-encrypted connection.
Improve documentation; notably, document the fact that libpq now
prefers GSS encryption over SSL encryption if both are possible.
Per report from Mikael Gustavsson. Back-patch to v12 where
this code was introduced.
Discussion: https://postgr.es/m/e5b0b6ed05764324a2f3fe7acfc766d5@smhi.se
The patch needs test cases, reorganization, and cfbot testing.
Technically reverts commits 5c31afc49d..e35b2bad1a (exclusive/inclusive)
and 08db7c63f3..ccbe34139b.
Reported-by: Tom Lane, Michael Paquier
Discussion: https://postgr.es/m/E1ktAAG-0002V2-VB@gemulon.postgresql.org
This adds a key management system that stores (currently) two data
encryption keys of length 128, 192, or 256 bits. The data keys are
AES256 encrypted using a key encryption key, and validated via GCM
cipher mode. A command to obtain the key encryption key must be
specified at initdb time, and will be run at every database server
start. New parameters allow a file descriptor open to the terminal to
be passed. pg_upgrade support has also been added.
Discussion: https://postgr.es/m/CA+fd4k7q5o6Nc_AaX6BcYM9yqTbC6_pnH-6nSD=54Zp6NBQTCQ@mail.gmail.com
Discussion: https://postgr.es/m/20201202213814.GG20285@momjian.us
Author: Masahiko Sawada, me, Stephen Frost
If a database shutdown (smart or fast) is commanded between the time
some process decides to request a new background worker and the time
that the postmaster can launch that worker, then nothing happens
because the postmaster won't launch any bgworkers once it's exited
PM_RUN state. This is fine ... unless the requesting process is
waiting for that worker to finish (or even for it to start); in that
case the requestor is stuck, and only manual intervention will get us
to the point of being able to shut down.
To fix, cancel pending requests for workers when the postmaster sends
shutdown (SIGTERM) signals, and similarly cancel any new requests that
arrive after that point. (We can optimize things slightly by only
doing the cancellation for workers that have waiters.) To fit within
the existing bgworker APIs, the "cancel" is made to look like the
worker was started and immediately stopped, causing deregistration of
the bgworker entry. Waiting processes would have to deal with
premature worker exit anyway, so this should introduce no bugs that
weren't there before. We do have a side effect that registration
records for restartable bgworkers might disappear when theoretically
they should have remained in place; but since we're shutting down,
that shouldn't matter.
Back-patch to v10. There might be value in putting this into 9.6
as well, but the management of bgworkers is a bit different there
(notably see 8ff518699) and I'm not convinced it's worth the effort
to validate the patch for that branch.
Discussion: https://postgr.es/m/661570.1608673226@sss.pgh.pa.us
Up to now, if the DBA issued "pg_ctl stop -m immediate", the message
sent to clients was the same as for a crash-and-restart situation.
This is confusing, not least because the message claims that the
database will soon be up again, something we have no business
predicting.
Improve things so that we can generate distinct messages for the two
cases (and also recognize an ad-hoc SIGQUIT, should somebody try that).
To do that, add a field to pmsignal.c's shared memory data structure
that the postmaster sets just before broadcasting SIGQUIT to its
children. No interlocking seems to be necessary; the intervening
signal-sending and signal-receipt should sufficiently serialize accesses
to the field. Hence, this isn't any riskier than the existing usages
of pmsignal.c.
We might in future extend this idea to improve other
postmaster-to-children signal scenarios, although none of them
currently seem to be as badly overloaded as SIGQUIT.
Discussion: https://postgr.es/m/559291.1608587013@sss.pgh.pa.us
Same type of issue as in commit 53d4f5fef and earlier fixes; also
found by apparently-more-picky-than-the-buildfarm valgrind testing.
This one is an oversight in commit 986816750. Since that's new in
HEAD, no need for a back-patch.
Revert ac22929a26, as well as the followup fix 113d3591b8. Because it broke
the assumption that the startup process waiting for the recovery conflict
on buffer pin should be waken up only by buffer unpin or the timeout enabled
in ResolveRecoveryConflictWithBufferPin(). It caused, for example,
SIGHUP signal handler or walreceiver process to wake that startup process
up unnecessarily frequently.
Additionally, add the comments about why that dedicated latch that
the reverted patch tried to get rid of should not be removed.
Thanks to Kyotaro Horiguchi for the discussion.
Author: Fujii Masao
Discussion: https://postgr.es/m/d8c0c608-021b-3c73-fffd-3240829ee986@oss.nttdata.com
Invent a new flag bit HASH_STRINGS to specify C-string hashing, which
was formerly the default; and add assertions insisting that exactly
one of the bits HASH_STRINGS, HASH_BLOBS, and HASH_FUNCTION be set.
This is in hopes of preventing recurrences of the type of oversight
fixed in commit a1b8aa1e4 (i.e., mistakenly omitting HASH_BLOBS).
Also, when HASH_STRINGS is specified, insist that the keysize be
more than 8 bytes. This is a heuristic, but it should catch
accidental use of HASH_STRINGS for integer or pointer keys.
(Nearly all existing use-cases set the keysize to NAMEDATALEN or
more, so there's little reason to think this restriction should
be problematic.)
Tweak hash_create() to insist that the HASH_ELEM flag be set, and
remove the defaults it had for keysize and entrysize. Since those
defaults were undocumented and basically useless, no callers
omitted HASH_ELEM anyway.
Also, remove memset's zeroing the HASHCTL parameter struct from
those callers that had one. This has never been really necessary,
and while it wasn't a bad coding convention it was confusing that
some callers did it and some did not. We might as well save a few
cycles by standardizing on "not".
Also improve the documentation for hash_create().
In passing, improve reinit.c's usage of a hash table by storing
the key as a binary Oid rather than a string; and, since that's
a temporary hash table, allocate it in CurrentMemoryContext for
neatness.
Discussion: https://postgr.es/m/590625.1607878171@sss.pgh.pa.us
After autovacuum collects the relations to vacuum or analyze, it rechecks
whether each relation still needs to be vacuumed or analyzed before actually
doing that. Previously this recheck could be a significant overhead
especially when there were a very large number of relations. This was
because each recheck forced the statistics to be refreshed, and the refresh
of the statistics for a very large number of relations could cause heavy
overhead. There was the report that this issue caused autovacuum workers
to have gotten “stuck” in a tight loop of table_recheck_autovac() that
rechecks whether a relation needs to be vacuumed or analyzed.
This commit speeds up the recheck by making autovacuum worker reuse
the previously-read statistics for the recheck if possible. Then if that
"stale" statistics says that a relation still needs to be vacuumed or analyzed,
autovacuum refreshes the statistics and does the recheck again.
The benchmark shows that the more relations exist and autovacuum workers
are running concurrently, the more this change reduces the autovacuum
execution time. For example, when there are 20,000 tables and 10 autovacuum
workers are running, the benchmark showed that the change improved
the performance of autovacuum more than three times. On the other hand,
even when there are only 1000 tables and only a single autovacuum worker
is running, the benchmark didn't show any big performance regression by
the change.
Firstly POC patch was proposed by Jim Nasby. As the result of discussion,
we used Tatsuhito Kasahara's version of the patch using the approach
suggested by Tom Lane.
Reported-by: Jim Nasby
Author: Tatsuhito Kasahara
Reviewed-by: Masahiko Sawada, Fujii Masao
Discussion: https://postgr.es/m/3FC6C2F2-8A47-44C0-B997-28830B5716D0@amazon.com
User-visible log messages should go through ereport(), so they are
subject to translation. Many remaining elog(LOG) calls are really
debugging calls.
Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
Reviewed-by: Michael Paquier <michael@paquier.xyz>
Reviewed-by: Noah Misch <noah@leadboat.com>
Discussion: https://www.postgresql.org/message-id/flat/92d6f545-5102-65d8-3c87-489f71ea0a37%40enterprisedb.com
Commit 6b466bf5f2 allowed pg_stat_statements to track the number of
WAL records, full page images and bytes that each statement generated.
Similarly this commit allows us to track the cluster-wide WAL statistics
counters.
New columns wal_records, wal_fpi and wal_bytes are added into the
pg_stat_wal view, and reports the total number of WAL records,
full page images and bytes generated in the , respectively.
Author: Masahiro Ikeda
Reviewed-by: Amit Kapila, Movead Li, Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/35ef960128b90bfae3b3fdf60a3a860f@oss.nttdata.com
Currently only OpenSSL requires this initialization, but in the future
other SSL implementations are likely to need it as well. Abstracting
this functionality out into a separate function makes this cleaner and
more clear, and also removes the dependency on OpenSSL headers from
fork_process.c.
OpenSSL is special in that we need to initialize this random number
generator even if we're not going to use it directly, until we drop
support for everything prior to OpenSSL 1.1.1. (And of course also if we
actually use it). All other implementations are left empty at this time,
but more are expected to be added in the future.
Author: Daniel Gustafsson <daniel@yesql.se>, Michael Paquier <michael@paquier.xyz>
Reviewed-By: Magnus Hagander <magnus@hagander.net>
Discussion: https://postgr.es/m/F6291C3C-747C-4C93-BCE0-28BB420B1FF5@yesql.se
There is no outright bug here but it is better to be consistent with the
usage at other places in the same file. In the passing, fix a wrong
assertion in pgstat_recv_replslot.
Author: Kyotaro Horiguchi
Reviewed-by: Sawada Masahiko and Amit Kapila
Discussion: https://postgr.es/m/20201104.175523.1704166915688949637.horikyota.ntt@gmail.com
This commit gets rid of the dedicated latch for signaling the startup
process in favor of using its procLatch, since that comports better
with possible generic signal handlers using that latch.
Commit 1e53fe0e70 changed background processes so that they use standard
SIGHUP handler. Like that, this commit also makes the startup process use
standard SIGHUP handler to simplify the code.
Author: Fujii Masao
Reviewed-by: Bharath Rupireddy, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACXPorUqePswDtOeM_s82v9RW32E1fYmOPZ5NuE+TWKj_A@mail.gmail.com
This adds the statistics about transactions streamed to the decoding
output plugin from ReorderBuffer. Users can query the
pg_stat_replication_slots view to check these stats and call
pg_stat_reset_replication_slot to reset the stats of a particular slot.
Users can pass NULL in pg_stat_reset_replication_slot to reset stats of
all the slots.
Commit 9868167500 has added the basic infrastructure to capture the stats
of slot and this commit extends the statistics collector to track
additional information about slots.
Bump the catversion as we have added new columns in the catalog entry.
Author: Ajin Cherian and Amit Kapila
Reviewed-by: Sawada Masahiko and Dilip Kumar
Discussion: https://postgr.es/m/CAA4eK1+chpEomLzgSoky-D31qev19AmECNiEAietPQUGEFhtVA@mail.gmail.com
This adds the statistics about transactions spilled to disk from
ReorderBuffer. Users can query the pg_stat_replication_slots view to check
these stats and call pg_stat_reset_replication_slot to reset the stats of
a particular slot. Users can pass NULL in pg_stat_reset_replication_slot
to reset stats of all the slots.
This commit extends the statistics collector to track this information
about slots.
Author: Sawada Masahiko and Amit Kapila
Reviewed-by: Amit Kapila and Dilip Kumar
Discussion: https://postgr.es/m/CA+fd4k5_pPAYRTDrO2PbtTOe0eHQpBvuqmCr8ic39uTNmR49Eg@mail.gmail.com
This view shows the statistics about WAL activity. Currently it has only
two columns: wal_buffers_full and stats_reset. wal_buffers_full column
indicates the number of times WAL data was written to the disk because
WAL buffers got full. This information is useful when tuning wal_buffers.
stats_reset column indicates the time at which these statistics were
last reset.
pg_stat_wal view is also the basic infrastructure to expose other
various statistics about WAL activity later.
Bump PGSTAT_FILE_FORMAT_ID due to the change in pgstat format.
Bump catalog version.
Author: Masahiro Ikeda
Reviewed-by: Takayuki Tsunakawa, Kyotaro Horiguchi, Amit Kapila, Fujii Masao
Discussion: https://postgr.es/m/188bd3f2d2233cf97753b5ced02bb050@oss.nttdata.com
We decided that the policy established in commit 7634bd4f6 for
the bgwriter, checkpointer, walwriter, and walreceiver processes,
namely that they should accept SIGQUIT at all times, really ought
to apply uniformly to all postmaster children. Therefore, get
rid of the duplicative and inconsistent per-process code for
establishing that signal handler and removing SIGQUIT from BlockSig.
Instead, make InitPostmasterChild do it.
The handler set up by InitPostmasterChild is SignalHandlerForCrashExit,
which just summarily does _exit(2). In interactive backends, we
almost immediately replace that with quickdie, since we would prefer
to try to tell the client that we're dying. However, this patch is
changing the behavior of autovacuum (both launcher and workers), as
well as walsenders. Those processes formerly also used quickdie,
but AFAICS that was just mindless copy-and-paste: they don't have
any interactive client that's likely to benefit from being told this.
The stats collector continues to be an outlier, in that it thinks
SIGQUIT means normal exit. That should probably be changed for
consistency, but there's another patch set where that's being
dealt with, so I didn't do so here.
Discussion: https://postgr.es/m/644875.1599933441@sss.pgh.pa.us
We use the timestamp of the global statfile if we are not able to
determine it for a particular database in case the entry for that database
doesn't exist. However, we were using it even when the statfile is
corrupt.
As there is no user reported issue and it is not clear if there is any
impact of this on actual application so decided not to backpatch.
Reported-by: Amit Kapila
Author: Amit Kapila
Reviewed-by: Sawada Masahiko, Magnus Hagander and Alvaro Herrera
Discussion: https://postgr.es/m/CAA4eK1J3oTJKyVq6v7K4d3jD+vtnruG9fHRib6UuWWsrwAR6Aw@mail.gmail.com
The bgwriter, checkpointer, walwriter, and walreceiver processes
claimed to allow SIGQUIT "at all times". In reality SIGQUIT
would get re-blocked during error recovery, because we didn't
update the actual signal mask immediately, so sigsetjmp() would
save and reinstate a mask that includes SIGQUIT.
This appears to be simply a coding oversight. There's never a
good reason to hold off SIGQUIT in these processes, because it's
going to just call _exit(2) which should be safe enough, especially
since the postmaster is going to tear down shared memory afterwards.
Hence, stick in PG_SETMASK() calls to install the modified BlockSig
mask immediately.
Also try to improve the comments around sigsetjmp blocks. Most of
them were just referencing postgres.c, which is misleading because
actually postgres.c manages the signals differently.
No back-patch, since there's no evidence that this is causing any
problems in the field.
Discussion: https://postgr.es/m/CALDaNm1d1hHPZUg3xU4XjtWBOLCrA+-2cJcLpw-cePZ=GgDVfA@mail.gmail.com
Currently, no useful trace is left in the logs when the postmaster
is forced to use SIGKILL to shut down children that failed to respond
to SIGQUIT. Some questions were raised about how often that scenario
happens in the buildfarm, so let's add a LOG-level message showing
that it happened.
Discussion: https://postgr.es/m/1850884.1599601164@sss.pgh.pa.us
Although 58c6feccf fixed the case for SIGQUIT, we were still calling
proc_exit() from signal handlers for SIGTERM and timeout failures in
ProcessStartupPacket. Fortunately, at the point where that code runs,
we haven't yet connected to shared memory in any meaningful way, so
there is nothing we need to undo in shared memory. This means it
should be safe to use _exit(1) here, ie, not run any atexit handlers
but also inform the postmaster that it's not a crash exit.
To make sure nobody breaks the "nothing to undo" expectation, add
a cross-check that no on-shmem-exit or before-shmem-exit handlers
have been registered yet when we finish using these signal handlers.
This change is simple enough that maybe it could be back-patched,
but I won't risk that right now.
Discussion: https://postgr.es/m/1850884.1599601164@sss.pgh.pa.us
Bring the signal handling for startup-packet collection into line
with the policy established in commits bedadc732 and 8e19a8264,
namely don't risk running atexit callbacks when handling SIGQUIT.
Ideally, we'd not do so for SIGTERM or timeout interrupts either,
but that change seems a bit too risky for the back branches.
For now, just improve the comments in this area to describe the risk.
Also relocate where BackendInitialize re-disables these interrupts,
to minimize the code span where they're active. This doesn't buy
a whole lot of safety, but it can't hurt.
In passing, rename startup_die() to remove confusion about whether
it is for the startup process.
Like the previous commits, back-patch to all supported branches.
Discussion: https://postgr.es/m/1850884.1599601164@sss.pgh.pa.us
Commit 8e19a8264 changed the SIGQUIT handlers of almost all server
processes not to run atexit callbacks. The archiver process was
skipped, perhaps because it's not connected to shared memory; but
it's just as true here that running atexit callbacks in a signal
handler is unsafe. So let's make it work like the rest.
In HEAD and v13, we can use the common SignalHandlerForCrashExit
handler. Before that, just tweak pgarch_exit to use _exit(2)
explicitly.
Like the previous commit, back-patch to all supported branches.
Kyotaro Horiguchi, back-patching by me
Discussion: https://postgr.es/m/1850884.1599601164@sss.pgh.pa.us
Because sigsetjmp() will restore the initial state with signals blocked,
the code path in bgworker.c for reporting an error and exiting would
execute that way. Usually this is fairly harmless; but if a parallel
worker had an error message exceeding the shared-memory communication
buffer size (16K) it would lock up, because it would wait for a
resume-sending signal from its parallel leader which it would never
detect.
To fix, just unblock signals at the appropriate point.
This can be shown to fail back to 9.6. The lack of parallel query
infrastructure makes it difficult to provide a simple test case for
9.5; but I'm pretty sure the issue exists in some form there as well,
so apply the code change there too.
Vignesh C, reviewed by Bharath Rupireddy, Robert Haas, and myself
Discussion: https://postgr.es/m/CALDaNm1d1hHPZUg3xU4XjtWBOLCrA+-2cJcLpw-cePZ=GgDVfA@mail.gmail.com
To add support for streaming of in-progress transactions into the
built-in logical replication, we need to do three things:
* Extend the logical replication protocol, so identify in-progress
transactions, and allow adding additional bits of information (e.g.
XID of subtransactions).
* Modify the output plugin (pgoutput) to implement the new stream
API callbacks, by leveraging the extended replication protocol.
* Modify the replication apply worker, to properly handle streamed
in-progress transaction by spilling the data to disk and then
replaying them on commit.
We however must explicitly disable streaming replication during
replication slot creation, even if the plugin supports it. We
don't need to replicate the changes accumulated during this phase,
and moreover we don't have a replication connection open so we
don't have where to send the data anyway.
Author: Tomas Vondra, Dilip Kumar and Amit Kapila
Reviewed-by: Amit Kapila, Kuntal Ghosh and Ajin Cherian
Tested-by: Neha Sharma, Mahendra Singh Thalor and Ajin Cherian
Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
Historically, we've considered the state with relpages and reltuples
both zero as indicating that we do not know the table's tuple density.
This is problematic because it's impossible to distinguish "never yet
vacuumed" from "vacuumed and seen to be empty". In particular, a user
cannot use VACUUM or ANALYZE to override the planner's normal heuristic
that an empty table should not be believed to be empty because it is
probably about to get populated. That heuristic is a good safety
measure, so I don't care to abandon it, but there should be a way to
override it if the table is indeed intended to stay empty.
Hence, represent the initial state of ignorance by setting reltuples
to -1 (relpages is still set to zero), and apply the minimum-ten-pages
heuristic only when reltuples is still -1. If the table is empty,
VACUUM or ANALYZE (but not CREATE INDEX) will override that to
reltuples = relpages = 0, and then we'll plan on that basis.
This requires a bunch of fiddly little changes, but we can get rid of
some ugly kluges that were formerly needed to maintain the old definition.
One notable point is that FDWs' GetForeignRelSize methods will see
baserel->tuples = -1 when no ANALYZE has been done on the foreign table.
That seems like a net improvement, since those methods were formerly
also in the dark about what baserel->tuples = 0 really meant. Still,
it is an API change.
I bumped catversion because code predating this change would get confused
by seeing reltuples = -1.
Discussion: https://postgr.es/m/F02298E0-6EF4-49A1-BCB6-C484794D9ACC@thebuild.com
Allow BufFile to support temporary files that can be used by the single
backend when the corresponding files need to be survived across the
transaction and need to be opened and closed multiple times. Such files
need to be created as a member of a SharedFileSet.
Additionally, this commit implements the interface for BufFileTruncate to
allow files to be truncated up to a particular offset and extends the
BufFileSeek API to support the SEEK_END case. This also adds an option to
provide a mode while opening the shared BufFiles instead of always opening
in read-only mode.
These enhancements in BufFile interface are required for the upcoming
patch to allow the replication apply worker, to handle streamed
in-progress transactions.
Author: Dilip Kumar, Amit Kapila
Reviewed-by: Amit Kapila
Tested-by: Neha Sharma
Discussion: https://postgr.es/m/688b0b7f-2f6c-d827-c27b-216a8e3ea700@2ndquadrant.com
Similar to the previous commit this increases the chance that data
frequently needed by GetSnapshotData() stays in l2 cache. As we now
take care to not unnecessarily write to ProcGlobal->vacuumFlags, there
should be very few modifications to the ProcGlobal->vacuumFlags array.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Thomas Munro <thomas.munro@gmail.com>
Reviewed-By: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/20200301083601.ews6hz5dduc3w2se@alap3.anarazel.de
Up to now, upon receipt of a SIGTERM ("smart shutdown" command), the
postmaster has immediately killed all "optional" background processes,
and subsequently refused to launch new ones while it's waiting for
foreground client processes to exit. No doubt this seemed like an OK
policy at some point; but it's a pretty bad one now, because it makes
for a seriously degraded environment for the remaining clients:
* Parallel queries are killed, and new ones fail to launch. (And our
parallel-query infrastructure utterly fails to deal with the case
in a reasonable way --- it just hangs waiting for workers that are
not going to arrive. There is more work needed in that area IMO.)
* Autovacuum ceases to function. We can tolerate that for awhile,
but if bulk-update queries continue to run in the surviving client
sessions, there's eventually going to be a mess. In the worst case
the system could reach a forced shutdown to prevent XID wraparound.
* The bgwriter and walwriter are also stopped immediately, likely
resulting in performance degradation.
Hence, let's rearrange things so that the only immediate change in
behavior is refusing to let in new normal connections. Once the last
normal connection is gone, shut everything down as though we'd received
a "fast" shutdown. To implement this, remove the PM_WAIT_BACKUP and
PM_WAIT_READONLY states, instead staying in PM_RUN or PM_HOT_STANDBY
while normal connections remain. A subsidiary state variable tracks
whether or not we're letting in new connections in those states.
This also allows having just one copy of the logic for killing child
processes in smart and fast shutdown modes. I moved that logic into
PostmasterStateMachine() by inventing a new state PM_STOP_BACKENDS.
Back-patch to 9.6 where parallel query was added. In principle
this'd be a good idea in 9.5 as well, but the risk/reward ratio
is not as good there, since lack of autovacuum is not a problem
during typical uses of smart shutdown.
Per report from Bharath Rupireddy.
Patch by me, reviewed by Thomas Munro
Discussion: https://postgr.es/m/CALj2ACXAZ5vKxT9P7P89D87i3MDO9bfS+_bjMHgnWJs8uwUOOw@mail.gmail.com
To make GetSnapshotData() more scalable, it cannot not look at at each proc's
xmin: While snapshot contents do not need to change whenever a read-only
transaction commits or a snapshot is released, a proc's xmin is modified in
those cases. The frequency of xmin modifications leads to, particularly on
higher core count systems, many cache misses inside GetSnapshotData(), despite
the data underlying a snapshot not changing. That is the most
significant source of GetSnapshotData() scaling poorly on larger systems.
Without accessing xmins, GetSnapshotData() cannot calculate accurate horizons /
thresholds as it has so far. But we don't really have to: The horizons don't
actually change that much between GetSnapshotData() calls. Nor are the horizons
actually used every time a snapshot is built.
The trick this commit introduces is to delay computation of accurate horizons
until there use and using horizon boundaries to determine whether accurate
horizons need to be computed.
The use of RecentGlobal[Data]Xmin to decide whether a row version could be
removed has been replaces with new GlobalVisTest* functions. These use two
thresholds to determine whether a row can be pruned:
1) definitely_needed, indicating that rows deleted by XIDs >= definitely_needed
are definitely still visible.
2) maybe_needed, indicating that rows deleted by XIDs < maybe_needed can
definitely be removed
GetSnapshotData() updates definitely_needed to be the xmin of the computed
snapshot.
When testing whether a row can be removed (with GlobalVisTestIsRemovableXid())
and the tested XID falls in between the two (i.e. XID >= maybe_needed && XID <
definitely_needed) the boundaries can be recomputed to be more accurate. As it
is not cheap to compute accurate boundaries, we limit the number of times that
happens in short succession. As the boundaries used by
GlobalVisTestIsRemovableXid() are never reset (with maybe_needed updated by
GetSnapshotData()), it is likely that further test can benefit from an earlier
computation of accurate horizons.
To avoid regressing performance when old_snapshot_threshold is set (as that
requires an accurate horizon to be computed), heap_page_prune_opt() doesn't
unconditionally call TransactionIdLimitedForOldSnapshots() anymore. Both the
computation of the limited horizon, and the triggering of errors (with
SetOldSnapshotThresholdTimestamp()) is now only done when necessary to remove
tuples.
This commit just removes the accesses to PGXACT->xmin from
GetSnapshotData(), but other members of PGXACT residing in the same
cache line are accessed. Therefore this in itself does not result in a
significant improvement. Subsequent commits will take advantage of the
fact that GetSnapshotData() now does not need to access xmins anymore.
Note: This contains a workaround in heap_page_prune_opt() to keep the
snapshot_too_old tests working. While that workaround is ugly, the tests
currently are not meaningful, and it seems best to address them separately.
Author: Andres Freund <andres@anarazel.de>
Reviewed-By: Robert Haas <robertmhaas@gmail.com>
Reviewed-By: Thomas Munro <thomas.munro@gmail.com>
Reviewed-By: David Rowley <dgrowleyml@gmail.com>
Discussion: https://postgr.es/m/20200301083601.ews6hz5dduc3w2se@alap3.anarazel.de
This had gotten a little disjointed over time, and some of the grammar
was sloppy. Rewrite for more clarity.
In passing, re-pgindent some recently added comments.
No code changes.
They are equivalent, except that StrNCpy() zero-fills the entire
destination buffer instead of providing just one trailing zero. For
all but a tiny number of callers, that's just overhead rather than
being desirable.
Remove StrNCpy() as it is now unused.
In some cases, namestrcpy() is the more appropriate function to use.
While we're here, simplify the API of namestrcpy(): Remove the return
value, don't check for NULL input. Nothing was using that anyway.
Also, remove a few unused name-related functions.
Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us>
Discussion: https://www.postgresql.org/message-id/flat/44f5e198-36f6-6cdb-7fa9-60e34784daae%402ndquadrant.com
Create LatchWaitSet at backend startup time, and use it to implement
WaitLatch(). This avoids repeated epoll/kqueue setup and teardown
system calls.
Reorder SubPostmasterMain() slightly so that we restore the postmaster
pipe and Windows signal emulation before we reach InitPostmasterChild(),
to make this work in EXEC_BACKEND builds.
Reviewed-by: Kyotaro Horiguchi <horikyota.ntt@gmail.com>
Discussion: https://postgr.es/m/CA%2BhUKGJAC4Oqao%3DqforhNey20J8CiG2R%3DoBPqvfR0vOJrFysGw%40mail.gmail.com
Thomas Munro
Michael Paquier
Amit Kapila
Tom Lane
Heikki Linnakangas
Peter Eisentraut
Robert Haas
Fujii Masao
Bruce Momjian
Daniel Gustafsson
Alvaro Herrera
Andres Freund
Magnus Hagander
Peter Geoghegan
Etsuro Fujita
Stephen Frost
Tomas Vondra