20 Commits (8c12838001c2d974d3608fe55c228f601818a729)

Author	SHA1	Message	Date
Thomas Munro	8fba928fd7	Improve the naming of Parallel Hash Join phases. ... * Commit 3048898e dropped -ING from PHJ wait event names. Update the corresponding barrier phases names to match. * Rename the "DONE" phases to "FREE". That's symmetrical with "ALLOCATE", and names the activity that actually happens in that phase (as we do for the other phases) rather than a state. The bug fixed by commit 8d578b9b might have been more obvious with this name. * Rename the batch/bucket growth barriers' "ALLOCATE" phases to "REALLOCATE", a better description of what they do. * Update the high level comments about phases to highlight phases are executed by a single process with an asterisk (mostly memory management phases). No behavior change, as this is just improving internal identifiers. The only user-visible sign of this is that a couple of wait events' display names change from "...Allocate" to "...Reallocate" in pg_stat_activity, to stay in sync with the internal names. Reviewed-by: Melanie Plageman <melanieplageman@gmail.com> Discussion: https://postgr.es/m/CA%2BhUKG%2BMDpwF2Eo2LAvzd%3DpOh81wUTsrwU1uAwR-v6OGBB6%2B7g%40mail.gmail.com	3 years ago
Amit Kapila	fce003cfde	Add a new wait state and use it when sending data in the apply worker. ... d9d7fe68d3 made use of an existing wait event when sending data from the apply worker, but we should have invented a new wait event since this is a new place to wait. This patch corrects the mistake by using a new wait event "LogicalApplySendData". Author: Hou Zhijie Reviewed-by: Peter Smith Discussion: https://postgr.es/m/CA+TgmobWzbr9H3yN3dLVckviEZKemPwd+XyCFKEgyZQZhgP66Q@mail.gmail.com	3 years ago
Amit Kapila	216a784829	Perform apply of large transactions by parallel workers. ... Currently, for large transactions, the publisher sends the data in multiple streams (changes divided into chunks depending upon logical_decoding_work_mem), and then on the subscriber-side, the apply worker writes the changes into temporary files and once it receives the commit, it reads from those files and applies the entire transaction. To improve the performance of such transactions, we can instead allow them to be applied via parallel workers. In this approach, we assign a new parallel apply worker (if available) as soon as the xact's first stream is received and the leader apply worker will send changes to this new worker via shared memory. The parallel apply worker will directly apply the change instead of writing it to temporary files. However, if the leader apply worker times out while attempting to send a message to the parallel apply worker, it will switch to "partial serialize" mode - in this mode, the leader serializes all remaining changes to a file and notifies the parallel apply workers to read and apply them at the end of the transaction. We use a non-blocking way to send the messages from the leader apply worker to the parallel apply to avoid deadlocks. We keep this parallel apply assigned till the transaction commit is received and also wait for the worker to finish at commit. This preserves commit ordering and avoid writing to and reading from files in most cases. We still need to spill if there is no worker available. This patch also extends the SUBSCRIPTION 'streaming' parameter so that the user can control whether to apply the streaming transaction in a parallel apply worker or spill the change to disk. The user can set the streaming parameter to 'on/off', or 'parallel'. The parameter value 'parallel' means the streaming will be applied via a parallel apply worker, if available. The parameter value 'on' means the streaming transaction will be spilled to disk. The default value is 'off' (same as current behaviour). In addition, the patch extends the logical replication STREAM_ABORT message so that abort_lsn and abort_time can also be sent which can be used to update the replication origin in parallel apply worker when the streaming transaction is aborted. Because this message extension is needed to support parallel streaming, parallel streaming is not supported for publications on servers < PG16. Author: Hou Zhijie, Wang wei, Amit Kapila with design inputs from Sawada Masahiko Reviewed-by: Sawada Masahiko, Peter Smith, Dilip Kumar, Shi yu, Kuroda Hayato, Shveta Mallik Discussion: https://postgr.es/m/CAA4eK1+wyN6zpaHUkCLorEWNx75MG0xhMwcFhvjqm2KURZEAGw@mail.gmail.com	3 years ago
Bruce Momjian	c8e1ba736b	Update copyright for 2023 ... Backpatch-through: 11	3 years ago
Andres Freund	92daeca45d	Add wait event for pg_usleep() in perform_spin_delay() ... The lwlock wait queue scalability issue fixed in a4adc31f69 was quite hard to find because of the exponential backoff and because we adjust spins_per_delay over time within a backend. To make it easier to find similar issues in the future, add a wait event for the pg_usleep() in perform_spin_delay(). Showing a wait event while spinning without sleeping would increase the overhead of spinlocks, which we do not want. We may at some later point want to have more granular wait events, but that'd be a substantial amount of work. This provides at least some insights into something currently hard to observe. Reviewed-by: Michael Paquier <michael@paquier.xyz> Reviewed-by: Robert Haas <robertmhaas@gmail.com> Reviewed-by: Alexander Korotkov <aekorotkov@gmail.com> https://postgr.es/m/20221120204310.xywrhyxyytsajuuq@awork3.anarazel.de	3 years ago
Robert Haas	d8cd0c6c95	Remove the restriction that the relmap must be 512 bytes. ... Instead of relying on the ability to atomically overwrite the entire relmap file in one shot, write a new one and durably rename it into place. Removing the struct padding and the calculation showing why the map is exactly 512 bytes, and change the maximum number of entries to a nearby round number. Patch by me, reviewed by Andres Freund and Dilip Kumar. Discussion: http://postgr.es/m/CA+TgmoZq5%3DLWDK7kHaUbmWXxcaTuw_QwafgG9dr-BaPym_U8WQ%40mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-ttOXLX75k_WzRo9ar=VvxFhrHi+rJxns997F+yvkm==A@mail.gmail.com	3 years ago
Thomas Munro	7bae3bbf62	Create a distinct wait event for POSIX DSM allocation. ... Previously we displayed "DSMFillZeroWrite" while in posix_fallocate(), because we shared the same wait event for "mmap" and "posix" DSM types. Let's introduce a new wait event "DSMAllocate", to be more accurate. Reported-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20220711174518.yldckniicknsxgzl%40awork3.anarazel.de	4 years ago
Andres Freund	5891c7a8ed	pgstat: store statistics in shared memory. ... Previously the statistics collector received statistics updates via UDP and shared statistics data by writing them out to temporary files regularly. These files can reach tens of megabytes and are written out up to twice a second. This has repeatedly prevented us from adding additional useful statistics. Now statistics are stored in shared memory. Statistics for variable-numbered objects are stored in a dshash hashtable (backed by dynamic shared memory). Fixed-numbered stats are stored in plain shared memory. The header for pgstat.c contains an overview of the architecture. The stats collector is not needed anymore, remove it. By utilizing the transactional statistics drop infrastructure introduced in a prior commit statistics entries cannot "leak" anymore. Previously leaked statistics were dropped by pgstat_vacuum_stat(), called from [auto-]vacuum. On systems with many small relations pgstat_vacuum_stat() could be quite expensive. Now that replicas drop statistics entries for dropped objects, it is not necessary anymore to reset stats when starting from a cleanly shut down replica. Subsequent commits will perform some further code cleanup, adapt docs and add tests. Bumps PGSTAT_FILE_FORMAT_ID. Author: Kyotaro Horiguchi <horikyota.ntt@gmail.com> Author: Andres Freund <andres@anarazel.de> Author: Melanie Plageman <melanieplageman@gmail.com> Reviewed-By: Andres Freund <andres@anarazel.de> Reviewed-By: Thomas Munro <thomas.munro@gmail.com> Reviewed-By: Justin Pryzby <pryzby@telsasoft.com> Reviewed-By: "David G. Johnston" <david.g.johnston@gmail.com> Reviewed-By: Tomas Vondra <tomas.vondra@2ndquadrant.com> (in a much earlier version) Reviewed-By: Arthur Zakirov <a.zakirov@postgrespro.ru> (in a much earlier version) Reviewed-By: Antonin Houska <ah@cybertec.at> (in a much earlier version) Discussion: https://postgr.es/m/20220303021600.hs34ghqcw6zcokdh@alap3.anarazel.de Discussion: https://postgr.es/m/20220308205351.2xcn6k4x5yivcxyd@alap3.anarazel.de Discussion: https://postgr.es/m/20210319235115.y3wz7hpnnrshdyv6@alap3.anarazel.de	4 years ago
Robert Haas	9c08aea6a3	Add new block-by-block strategy for CREATE DATABASE. ... Because this strategy logs changes on a block-by-block basis, it avoids the need to checkpoint before and after the operation. However, because it logs each changed block individually, it might generate a lot of extra write-ahead logging if the template database is large. Therefore, the older strategy remains available via a new STRATEGY parameter to CREATE DATABASE, and a corresponding --strategy option to createdb. Somewhat controversially, this patch assembles the list of relations to be copied to the new database by reading the pg_class relation of the template database. Cross-database access like this isn't normally possible, but it can be made to work here because there can't be any connections to the database being copied, nor can it contain any in-doubt transactions. Even so, we have to use lower-level interfaces than normal, since the table scan and relcache interfaces will not work for a database to which we're not connected. The advantage of this approach is that we do not need to rely on the filesystem to determine what ought to be copied, but instead on PostgreSQL's own knowledge of the database structure. This avoids, for example, copying stray files that happen to be located in the source database directory. Dilip Kumar, with a fairly large number of cosmetic changes by me. Reviewed and tested by Ashutosh Sharma, Andres Freund, John Naylor, Greg Nancarrow, Neha Sharma. Additional feedback from Bruce Momjian, Heikki Linnakangas, Julien Rouhaud, Adam Brusselback, Kyotaro Horiguchi, Tomas Vondra, Andrew Dunstan, Álvaro Herrera, and others. Discussion: http://postgr.es/m/CA+TgmoYtcdxBjLh31DLxUXHxFVMPGzrU5_T=CYCvRyFHywSBUQ@mail.gmail.com	4 years ago
Thomas Munro	3390ef1b7b	Fix waiting in RegisterSyncRequest(). ... If we run out of space in the checkpointer sync request queue (which is hopefully rare on real systems, but common with very small buffer pool), we wait for it to drain. While waiting, we should report that as a wait event so that users know what is going on, and also handle postmaster death, since otherwise the loop might never terminate if the checkpointer has exited. Back-patch to 12. Although the problem exists in earlier releases too, the code is structured differently before 12 so I haven't gone any further for now, in the absence of field complaints. Reported-by: Andres Freund <andres@anarazel.de> Reviewed-by: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20220226213942.nb7uvb2pamyu26dj%40alap3.anarazel.de	4 years ago
Thomas Munro	5e6368b42e	Wake up for latches in CheckpointWriteDelay(). ... 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	4 years ago
Robert Haas	3500ccc39b	Support base backup targets. ... pg_basebackup now has a --target=TARGET[:DETAIL] option. If specfied, it is sent to the server as the value of the TARGET option to the BASE_BACKUP command. If DETAIL is included, it is sent as the value of the new TARGET_DETAIL option to the BASE_BACKUP command. If the target is anything other than 'client', pg_basebackup assumes that it will now be the server's job to write the backup in a location somehow defined by the target, and that it therefore needs to write nothing locally. However, the server will still send messages to the client for progress reporting purposes. On the server side, we now support two additional types of backup targets. There is a 'blackhole' target, which just throws away the backup data without doing anything at all with it. Naturally, this should only be used for testing and debugging purposes, since you will not actually have a backup when it finishes running. More usefully, there is also a 'server' target, so you can now use something like 'pg_basebackup -Xnone -t server:/SOME/PATH' to write a backup to some location on the server. We can extend this to more types of targets in the future, and might even want to create an extensibility mechanism for adding new target types. Since WAL fetching is handled with separate client-side logic, it's not part of this mechanism; thus, backups with non-default targets must use -Xnone or -Xfetch. Patch by me, with a bug fix by Jeevan Ladhe. The patch set of which this is a part has also had review and/or testing from Tushar Ahuja, Suraj Kharage, Dipesh Pandit, and Mark Dilger. Discussion: http://postgr.es/m/CA+TgmoaYZbz0=Yk797aOJwkGJC-LK3iXn+wzzMx7KdwNpZhS5g@mail.gmail.com	4 years ago
Bruce Momjian	27b77ecf9f	Update copyright for 2022 ... Backpatch-through: 10	4 years ago
Fujii Masao	1b06d7bac9	Report wait events for local shell commands like archive_command. ... This commit introduces new wait events for archive_command, archive_cleanup_command, restore_command and recovery_end_command. Author: Fujii Masao Reviewed-by: Bharath Rupireddy, Michael Paquier Discussion: https://postgr.es/m/4ca4f920-6b48-638d-08b2-93598356f5d3@oss.nttdata.com	4 years ago
Amit Kapila	1607cd0b6c	Remove unused wait events. ... Commit 464824323e introduced the wait events which were neither used by that commit nor by follow-up commits for that work. Author: Masahiro Ikeda Backpatch-through: 14, where it was introduced Discussion: https://postgr.es/m/ff077840-3ab2-04dd-bbe4-4f5dfd2ad481@oss.nttdata.com	4 years ago
Michael Paquier	70685385d7	Use WaitLatch() instead of pg_usleep() at end-of-vacuum truncation ... This has the advantage to make a process more responsive when the postmaster dies, even if the wait time was rather limited as there was only a 50ms timeout here. Another advantage of this change is for monitoring, as we gain a new wait event for the end-of-vacuum truncation. Author: Bharath Rupireddy Reviewed-by: Aleksander Alekseev, Thomas Munro, Michael Paquier Discussion: https://postgr.es/m/CALj2ACU4AdPCq6NLfcA-ZGwX7pPCK5FgEj-CAU0xCKzkASSy_A@mail.gmail.com	5 years ago
Tom Lane	def5b065ff	Initial pgindent and pgperltidy run for v14. ... 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.	5 years ago
Magnus Hagander	aaf0432572	Add functions to wait for backend termination ... This adds a function, pg_wait_for_backend_termination(), and a new timeout argument to pg_terminate_backend(), which will wait for the backend to actually terminate (with or without signaling it to do so depending on which function is called). The default behaviour of pg_terminate_backend() remains being timeout=0 which does not waiting. For pg_wait_for_backend_termination() the default wait is 5 seconds. Author: Bharath Rupireddy Reviewed-By: Fujii Masao, David Johnston, Muhammad Usama, Hou Zhijie, Magnus Hagander Discussion: https://postgr.es/m/CALj2ACUBpunmyhYZw-kXCYs5NM+h6oG_7Df_Tn4mLmmUQifkqA@mail.gmail.com	5 years ago
Andres Freund	225a22b19e	Improve efficiency of wait event reporting, remove proc.h dependency. ... pgstat_report_wait_start() and pgstat_report_wait_end() required two conditional branches so far. One to check if MyProc is NULL, the other to check if pgstat_track_activities is set. As wait events are used around comparatively lightweight operations, and are inlined (reducing branch predictor effectiveness), that's not great. The dependency on MyProc has a second disadvantage: Low-level subsystems, like storage/file/fd.c, report wait events, but architecturally it is preferable for them to not depend on inter-process subsystems like proc.h (defining PGPROC). After this change including pgstat.h (nor obviously its sub-components like backend_status.h, wait_event.h, ...) does not pull in IPC related headers anymore. These goals, efficiency and abstraction, are achieved by having pgstat_report_wait_start/end() not interact with MyProc, but instead a new my_wait_event_info variable. At backend startup it points to a local variable, removing the need to check for MyProc being NULL. During process initialization my_wait_event_info is redirected to MyProc->wait_event_info. At shutdown this is reversed. Because wait event reporting now does not need to know about where the wait event is stored, it does not need to know about PGPROC anymore. The removal of the branch for checking pgstat_track_activities is simpler: Don't check anymore. The cost due to the branch are often higher than the store - and even if not, pgstat_track_activities is rarely disabled. The main motivator to commit this work now is that removing the (indirect) pgproc.h include from pgstat.h simplifies a patch to move statistics reporting to shared memory (which still has a chance to get into 14). Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20210402194458.2vu324hkk2djq6ce@alap3.anarazel.de	5 years ago
Andres Freund	a333476b92	Split wait event related code from pgstat.[ch] into wait_event.[ch]. ... 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	5 years ago