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path: root/src/backend/replication/syncrep.c
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2024-05-17Revise GUC names quoting in messages againPeter Eisentraut
After further review, we want to move in the direction of always quoting GUC names in error messages, rather than the previous (PG16) wildly mixed practice or the intermittent (mid-PG17) idea of doing this depending on how possibly confusing the GUC name is. This commit applies appropriate quotes to (almost?) all mentions of GUC names in error messages. It partially supersedes a243569bf65 and 8d9978a7176, which had moved things a bit in the opposite direction but which then were abandoned in a partial state. Author: Peter Smith <[email protected]> Discussion: https://www.postgresql.org/message-id/flat/CAHut%2BPv-kSN8SkxSdoHano_wPubqcg5789ejhCDZAcLFceBR-w%40mail.gmail.com
2024-03-04Remove unused #include's from backend .c filesPeter Eisentraut
as determined by include-what-you-use (IWYU) While IWYU also suggests to *add* a bunch of #include's (which is its main purpose), this patch does not do that. In some cases, a more specific #include replaces another less specific one. Some manual adjustments of the automatic result: - IWYU currently doesn't know about includes that provide global variable declarations (like -Wmissing-variable-declarations), so those includes are being kept manually. - All includes for port(ability) headers are being kept for now, to play it safe. - No changes of catalog/pg_foo.h to catalog/pg_foo_d.h, to keep the patch from exploding in size. Note that this patch touches just *.c files, so nothing declared in header files changes in hidden ways. As a small example, in src/backend/access/transam/rmgr.c, some IWYU pragma annotations are added to handle a special case there. Discussion: https://www.postgresql.org/message-id/flat/af837490-6b2f-46df-ba05-37ea6a6653fc%40eisentraut.org
2024-02-16Use new overflow-safe integer comparison functions.Nathan Bossart
Commit 6b80394781 introduced integer comparison functions designed to be as efficient as possible while avoiding overflow. This commit makes use of these functions in many of the in-tree qsort() comparators to help ensure transitivity. Many of these comparator functions should also see a small performance boost. Author: Mats Kindahl Reviewed-by: Andres Freund, Fabrízio de Royes Mello Discussion: https://postgr.es/m/CA%2B14426g2Wa9QuUpmakwPxXFWG_1FaY0AsApkvcTBy-YfS6uaw%40mail.gmail.com
2024-01-04Update copyright for 2024Bruce Momjian
Reported-by: Michael Paquier Discussion: https://postgr.es/m/[email protected] Backpatch-through: 12
2023-12-27Fix incorrect format placeholdersPeter Eisentraut
2023-05-19Pre-beta mechanical code beautification.Tom Lane
Run pgindent, pgperltidy, and reformat-dat-files. This set of diffs is a bit larger than typical. We've updated to pg_bsd_indent 2.1.2, which properly indents variable declarations that have multi-line initialization expressions (the continuation lines are now indented one tab stop). We've also updated to perltidy version 20230309 and changed some of its settings, which reduces its desire to add whitespace to lines to make assignments etc. line up. Going forward, that should make for fewer random-seeming changes to existing code. Discussion: https://postgr.es/m/[email protected]
2023-05-02Fix typos in commentsMichael Paquier
The changes done in this commit impact comments with no direct user-visible changes, with fixes for incorrect function, variable or structure names. Author: Alexander Lakhin Discussion: https://postgr.es/m/[email protected]
2023-02-20Speedup and increase usability of set proc title functionsDavid Rowley
The setting of the process title could be seen on profiles of very fast-to-execute queries. In many locations where we call set_ps_display() we pass along a string constant, the length of which is known during compilation. Here we effectively rename set_ps_display() to set_ps_display_with_len() and then add a static inline function named set_ps_display() which calls strlen() on the given string. This allows the compiler to optimize away the strlen() call when dealing with call sites passing a string constant. We can then also use memcpy() instead of strlcpy() to copy the string into the destination buffer. That's significantly faster than strlcpy's byte-at-a-time way of copying. Here we also take measures to improve some code which was adjusting the process title to add a " waiting" suffix to it. Call sites which require this can now just call set_ps_display_suffix() to add or adjust the suffix and call set_ps_display_remove_suffix() to remove it again. Reviewed-by: Andres Freund Discussion: https://postgr.es/m/CAApHDvocBvvk-0gWNA2Gohe+sv9fMcv+fK_G+siBKJrgDG4O7g@mail.gmail.com
2023-01-18Use dlists instead of SHM_QUEUE for syncrep queueAndres Freund
Part of a series to remove SHM_QUEUE. ilist.h style lists are more widely used and have an easier to use interface. Reviewed-by: Thomas Munro <[email protected]> (in an older version) Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2023-01-02Update copyright for 2023Bruce Momjian
Backpatch-through: 11
2022-10-14Store GUC data in a memory context, instead of using malloc().Tom Lane
The only real argument for using malloc directly was that we needed the ability to not throw error on OOM; but mcxt.c grew that feature awhile ago. Keeping the data in a memory context improves accountability and debuggability --- for example, without this it's almost impossible to detect memory leaks in the GUC code with anything less costly than valgrind. Moreover, the next patch in this series will add a hash table for GUC lookup, and it'd be pretty silly to be using palloc-dependent hash facilities alongside malloc'd storage of the underlying data. This is a bit invasive though, in particular causing an API break for GUC check hooks that want to modify the GUC's value or use an "extra" data structure. They must now use guc_malloc() and guc_free() instead of malloc() and free(). Failure to change affected code will result in assertion failures or worse; but thanks to recent effort in the mcxt infrastructure, it shouldn't be too hard to diagnose such oversights (at least in assert-enabled builds). One note is that this changes ParseLongOption() to return short-lived palloc'd not malloc'd data. There wasn't any caller for which the previous definition was better. Discussion: https://postgr.es/m/[email protected]
2022-09-13Split up guc.c for better build speed and ease of maintenance.Tom Lane
guc.c has grown to be one of our largest .c files, making it a bottleneck for compilation. It's also acquired a bunch of knowledge that'd be better kept elsewhere, because of our not very good habit of putting variable-specific check hooks here. Hence, split it up along these lines: * guc.c itself retains just the core GUC housekeeping mechanisms. * New file guc_funcs.c contains the SET/SHOW interfaces and some SQL-accessible functions for GUC manipulation. * New file guc_tables.c contains the data arrays that define the built-in GUC variables, along with some already-exported constant tables. * GUC check/assign/show hook functions are moved to the variable's home module, whenever that's clearly identifiable. A few hard- to-classify hooks ended up in commands/variable.c, which was already a home for miscellaneous GUC hook functions. To avoid cluttering a lot more header files with #include "guc.h", I also invented a new header file utils/guc_hooks.h and put all the GUC hook functions' declarations there, regardless of their originating module. That allowed removal of #include "guc.h" from some existing headers. The fallout from that (hopefully all caught here) demonstrates clearly why such inclusions are best minimized: there are a lot of files that, for example, were getting array.h at two or more levels of remove, despite not having any connection at all to GUCs in themselves. There is some very minor code beautification here, such as renaming a couple of inconsistently-named hook functions and improving some comments. But mostly this just moves code from point A to point B and deals with the ensuing needs for #include adjustments and exporting a few functions that previously weren't exported. Patch by me, per a suggestion from Andres Freund; thanks also to Michael Paquier for the idea to invent guc_funcs.c. Discussion: https://postgr.es/m/[email protected]
2022-01-08Update copyright for 2022Bruce Momjian
Backpatch-through: 10
2021-05-12Initial pgindent and pgperltidy run for v14.Tom Lane
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.
2021-02-23Simplify printing of LSNsPeter Eisentraut
Add a macro LSN_FORMAT_ARGS for use in printf-style printing of LSNs. Convert all applicable code to use it. Reviewed-by: Ashutosh Bapat <[email protected]> Reviewed-by: Kyotaro Horiguchi <[email protected]> Reviewed-by: Michael Paquier <[email protected]> Discussion: https://www.postgresql.org/message-id/flat/CAExHW5ub5NaTELZ3hJUCE6amuvqAtsSxc7O+uK7y4t9Rrk23cw@mail.gmail.com
2021-02-17Use errmsg_internal for debug messagesPeter Eisentraut
An inconsistent set of debug-level messages was not using errmsg_internal(), thus uselessly exposing the messages to translation work. Fix those.
2021-01-02Update copyright for 2021Bruce Momjian
Backpatch-through: 9.5
2020-09-02Avoid unnecessary acquisition of SyncRepLock in transaction commit time.Fujii Masao
In SyncRepWaitForLSN() routine called in transaction commit time, SyncRepLock is necessary to atomically both check the shared sync_standbys_defined flag and operate the sync replication wait-queue. On the other hand, when the flag is false, the lock is not necessary because the wait-queue is not touched. But due to the changes by commit 48c9f49265, previously the lock was taken whatever the flag was. This could cause unnecessary performance overhead in every transaction commit time. Therefore this commit avoids that unnecessary aquisition of SyncRepLock. Author: Fujii Masao Reviewed-by: Asim Praveen, Masahiko Sawada, Discussion: https://postgr.es/m/[email protected]
2020-04-18Fix race conditions in synchronous standby management.Tom Lane
We have repeatedly seen the buildfarm reach the Assert(false) in SyncRepGetSyncStandbysPriority. This apparently is due to failing to consider the possibility that the sync_standby_priority values in shared memory might be inconsistent; but they will be whenever only some of the walsenders have updated their values after a change in the synchronous_standby_names setting. That function is vastly too complex for what it does, anyway, so rewriting it seems better than trying to apply a band-aid fix. Furthermore, the API of SyncRepGetSyncStandbys is broken by design: it returns a list of WalSnd array indexes, but there is nothing guaranteeing that the contents of the WalSnd array remain stable. Thus, if some walsender exits and then a new walsender process takes over that WalSnd array slot, a caller might make use of WAL position data that it should not, potentially leading to incorrect decisions about whether to release transactions that are waiting for synchronous commit. To fix, replace SyncRepGetSyncStandbys with a new function SyncRepGetCandidateStandbys that copies all the required data from shared memory while holding the relevant mutexes. If the associated walsender process then exits, this data is still safe to make release decisions with, since we know that that much WAL *was* sent to a valid standby server. This incidentally means that we no longer need to treat sync_standby_priority as protected by the SyncRepLock rather than the per-walsender mutex. SyncRepGetSyncStandbys is no longer used by the core code, so remove it entirely in HEAD. However, it seems possible that external code is relying on that function, so do not remove it from the back branches. Instead, just remove the known-incorrect Assert. When the bug occurs, the function will return a too-short list, which callers should treat as meaning there are not enough sync standbys, which seems like a reasonably safe fallback until the inconsistent state is resolved. Moreover it's bug-compatible with what has been happening in non-assert builds. We cannot do anything about the walsender-replacement race condition without an API/ABI break. The bogus assertion exists back to 9.6, but 9.6 is sufficiently different from the later branches that the patch doesn't apply at all. I chose to just remove the bogus assertion in 9.6, feeling that the probability of a bad outcome from the walsender-replacement race condition is too low to justify rewriting the whole patch for 9.6. Discussion: https://postgr.es/m/[email protected]
2020-03-11Refactor ps_status.c APIPeter Eisentraut
The init_ps_display() arguments were mostly lies by now, so to match typical usage, just use one argument and let the caller assemble it from multiple sources if necessary. The only user of the additional arguments is BackendInitialize(), which was already doing string assembly on the caller side anyway. Remove the second argument of set_ps_display() ("force") and just handle that in init_ps_display() internally. BackendInitialize() also used to set the initial status as "authentication", but that was very far from where authentication actually happened. So now it's set to "initializing" and then "authentication" just before the actual call to ClientAuthentication(). Reviewed-by: Julien Rouhaud <[email protected]> Reviewed-by: Kuntal Ghosh <[email protected]> Reviewed-by: Alvaro Herrera <[email protected]> Discussion: https://www.postgresql.org/message-id/flat/[email protected]
2020-01-01Update copyrights for 2020Bruce Momjian
Backpatch-through: update all files in master, backpatch legal files through 9.4
2019-11-01Add some assertions in syncrep.cMichael Paquier
A couple of routines assume that the LWLock SyncRepLock needs to be taken, so add a couple of assertions to be sure of that. Also, when waiting for a given LSN at transaction commit, the code implied that the syncrep queue cleanup happens while holding interrupts, but the code never checked after that. Author: Michael Paquier Reviewed-by: Fujii Masao, Kyotaro Horiguchi, Dongming Liu Discussion: https://postgr.es/m/[email protected]
2019-11-01Fix race condition at backend exit when deleting element in syncrep queueMichael Paquier
When a backend exits, it gets deleted from the syncrep queue if present. The queue was checked without SyncRepLock taken in exclusive mode, so it would have been possible for a backend to remove itself after a WAL sender already did the job. Fix this issue based on a suggestion from Fujii Masao, by first checking the queue without the lock. Then, if the backend is present in the queue, take the lock and perform an additional lookup check before doing the element deletion. Author: Dongming Liu Reviewed-by: Kyotaro Horiguchi, Fujii Masao, Michael Paquier Discussion: https://postgr.es/m/[email protected] Backpatch-through: 9.4
2019-10-31Fix typo in comment of syncrep.cMichael Paquier
Author: Kyotaro Horiguchi Discussion: https://postgr.es/m/[email protected]
2019-08-12Rationalize use of list_concat + list_copy combinations.Tom Lane
In the wake of commit 1cff1b95a, the result of list_concat no longer shares the ListCells of the second input. Therefore, we can replace "list_concat(x, list_copy(y))" with just "list_concat(x, y)". To improve call sites that were list_copy'ing the first argument, or both arguments, invent "list_concat_copy()" which produces a new list sharing no ListCells with either input. (This is a bit faster than "list_concat(list_copy(x), y)" because it makes the result list the right size to start with.) In call sites that were not list_copy'ing the second argument, the new semantics mean that we are usually leaking the second List's storage, since typically there is no remaining pointer to it. We considered inventing another list_copy variant that would list_free the second input, but concluded that for most call sites it isn't worth worrying about, given the relative compactness of the new List representation. (Note that in cases where such leakage would happen, the old code already leaked the second List's header; so we're only discussing the size of the leak not whether there is one. I did adjust two or three places that had been troubling to free that header so that they manually free the whole second List.) Patch by me; thanks to David Rowley for review. Discussion: https://postgr.es/m/[email protected]
2019-07-15Represent Lists as expansible arrays, not chains of cons-cells.Tom Lane
Originally, Postgres Lists were a more or less exact reimplementation of Lisp lists, which consist of chains of separately-allocated cons cells, each having a value and a next-cell link. We'd hacked that once before (commit d0b4399d8) to add a separate List header, but the data was still in cons cells. That makes some operations -- notably list_nth() -- O(N), and it's bulky because of the next-cell pointers and per-cell palloc overhead, and it's very cache-unfriendly if the cons cells end up scattered around rather than being adjacent. In this rewrite, we still have List headers, but the data is in a resizable array of values, with no next-cell links. Now we need at most two palloc's per List, and often only one, since we can allocate some values in the same palloc call as the List header. (Of course, extending an existing List may require repalloc's to enlarge the array. But this involves just O(log N) allocations not O(N).) Of course this is not without downsides. The key difficulty is that addition or deletion of a list entry may now cause other entries to move, which it did not before. For example, that breaks foreach() and sister macros, which historically used a pointer to the current cons-cell as loop state. We can repair those macros transparently by making their actual loop state be an integer list index; the exposed "ListCell *" pointer is no longer state carried across loop iterations, but is just a derived value. (In practice, modern compilers can optimize things back to having just one loop state value, at least for simple cases with inline loop bodies.) In principle, this is a semantics change for cases where the loop body inserts or deletes list entries ahead of the current loop index; but I found no such cases in the Postgres code. The change is not at all transparent for code that doesn't use foreach() but chases lists "by hand" using lnext(). The largest share of such code in the backend is in loops that were maintaining "prev" and "next" variables in addition to the current-cell pointer, in order to delete list cells efficiently using list_delete_cell(). However, we no longer need a previous-cell pointer to delete a list cell efficiently. Keeping a next-cell pointer doesn't work, as explained above, but we can improve matters by changing such code to use a regular foreach() loop and then using the new macro foreach_delete_current() to delete the current cell. (This macro knows how to update the associated foreach loop's state so that no cells will be missed in the traversal.) There remains a nontrivial risk of code assuming that a ListCell * pointer will remain good over an operation that could now move the list contents. To help catch such errors, list.c can be compiled with a new define symbol DEBUG_LIST_MEMORY_USAGE that forcibly moves list contents whenever that could possibly happen. This makes list operations significantly more expensive so it's not normally turned on (though it is on by default if USE_VALGRIND is on). There are two notable API differences from the previous code: * lnext() now requires the List's header pointer in addition to the current cell's address. * list_delete_cell() no longer requires a previous-cell argument. These changes are somewhat unfortunate, but on the other hand code using either function needs inspection to see if it is assuming anything it shouldn't, so it's not all bad. Programmers should be aware of these significant performance changes: * list_nth() and related functions are now O(1); so there's no major access-speed difference between a list and an array. * Inserting or deleting a list element now takes time proportional to the distance to the end of the list, due to moving the array elements. (However, it typically *doesn't* require palloc or pfree, so except in long lists it's probably still faster than before.) Notably, lcons() used to be about the same cost as lappend(), but that's no longer true if the list is long. Code that uses lcons() and list_delete_first() to maintain a stack might usefully be rewritten to push and pop at the end of the list rather than the beginning. * There are now list_insert_nth...() and list_delete_nth...() functions that add or remove a list cell identified by index. These have the data-movement penalty explained above, but there's no search penalty. * list_concat() and variants now copy the second list's data into storage belonging to the first list, so there is no longer any sharing of cells between the input lists. The second argument is now declared "const List *" to reflect that it isn't changed. This patch just does the minimum needed to get the new implementation in place and fix bugs exposed by the regression tests. As suggested by the foregoing, there's a fair amount of followup work remaining to do. Also, the ENABLE_LIST_COMPAT macros are finally removed in this commit. Code using those should have been gone a dozen years ago. Patch by me; thanks to David Rowley, Jesper Pedersen, and others for review. Discussion: https://postgr.es/m/[email protected]
2019-05-22Phase 2 pgindent run for v12.Tom Lane
Switch to 2.1 version of pg_bsd_indent. This formats multiline function declarations "correctly", that is with additional lines of parameter declarations indented to match where the first line's left parenthesis is. Discussion: https://postgr.es/m/CAEepm=0P3FeTXRcU5B2W3jv3PgRVZ-kGUXLGfd42FFhUROO3ug@mail.gmail.com
2019-05-22Initial pgindent run for v12.Tom Lane
This is still using the 2.0 version of pg_bsd_indent. I thought it would be good to commit this separately, so as to document the differences between 2.0 and 2.1 behavior. Discussion: https://postgr.es/m/[email protected]
2019-01-02Update copyright for 2019Bruce Momjian
Backpatch-through: certain files through 9.4
2018-11-29Fix handling of synchronous replication for stopping WAL sendersMichael Paquier
This fixes an oversight from c6c3334 which forgot that if a subset of WAL senders are stopping and in a sync state, other WAL senders could still be waiting for a WAL position to be synced while committing a transaction. However the subset of stopping senders would not release waiters, potentially breaking synchronous replication guarantees. This commit makes sure that even WAL senders stopping are able to release waiters and are tracked properly. On 9.4, this can also trigger an assertion failure when setting for example max_wal_senders to 1 where a WAL sender is not able to find itself as in synchronous state when the instance stops. Reported-by: Paul Guo Author: Paul Guo, Michael Paquier Discussion: https://postgr.es/m/CAEET0ZEv8VFqT3C-cQm6byOB4r4VYWcef1J21dOX-gcVhCSpmA@mail.gmail.com Backpatch-through: 9.4
2018-11-23Add WL_EXIT_ON_PM_DEATH pseudo-event.Thomas Munro
Users of the WaitEventSet and WaitLatch() APIs can now choose between asking for WL_POSTMASTER_DEATH and then handling it explicitly, or asking for WL_EXIT_ON_PM_DEATH to trigger immediate exit on postmaster death. This reduces code duplication, since almost all callers want the latter. Repair all code that was previously ignoring postmaster death completely, or requesting the event but ignoring it, or requesting the event but then doing an unconditional PostmasterIsAlive() call every time through its event loop (which is an expensive syscall on platforms for which we don't have USE_POSTMASTER_DEATH_SIGNAL support). Assert that callers of WaitLatchXXX() under the postmaster remember to ask for either WL_POSTMASTER_DEATH or WL_EXIT_ON_PM_DEATH, to prevent future bugs. The only process that doesn't handle postmaster death is syslogger. It waits until all backends holding the write end of the syslog pipe (including the postmaster) have closed it by exiting, to be sure to capture any parting messages. By using the WaitEventSet API directly it avoids the new assertion, and as a by-product it may be slightly more efficient on platforms that have epoll(). Author: Thomas Munro Reviewed-by: Kyotaro Horiguchi, Heikki Linnakangas, Tom Lane Discussion: https://postgr.es/m/CAEepm%3D1TCviRykkUb69ppWLr_V697rzd1j3eZsRMmbXvETfqbQ%40mail.gmail.com, https://postgr.es/m/CAEepm=2LqHzizbe7muD7-2yHUbTOoF7Q+qkSD5Q41kuhttRTwA@mail.gmail.com
2018-10-15Make spelling of "acknowledgment" consistentPeter Eisentraut
I used the preferred U.S. spelling, as we do in other cases.
2018-01-03Update copyright for 2018Bruce Momjian
Backpatch-through: certain files through 9.3
2017-12-29Fix race condition when changing synchronous_standby_namesSimon Riggs
A momentary window exists when synchronous_standby_names changes that allows commands issued after the change to continue to act as async until the change becomes visible. Remove the race by using more appropriate test in syncrep.c Author: Asim Rama Praveen and Ashwin Agrawal Reported-by: Xin Zhang, Ashwin Agrawal, and Asim Rama Praveen Reviewed-by: Michael Paquier, Masahiko Sawada
2017-08-14Final pgindent + perltidy run for v10.Tom Lane
2017-07-12Fix ordering of operations in SyncRepWakeQueue to avoid assertion failure.Heikki Linnakangas
Commit 14e8803f1 removed the locking in SyncRepWaitForLSN, but that introduced a race condition, where SyncRepWaitForLSN might see syncRepState already set to SYNC_REP_WAIT_COMPLETE, but the process was not yet removed from the queue. That tripped the assertion, that the process should no longer be in the uqeue. Reorder the operations in SyncRepWakeQueue to remove the process from the queue first, and update syncRepState only after that, and add a memory barrier in between to make sure the operations are made visible to other processes in that order. Fixes bug #14721 reported by Const Zhang. Analysis and fix by Thomas Munro. Backpatch down to 9.5, where the locking was removed. Discussion: https://www.postgresql.org/message-id/20170629023623.1480.26508%40wrigleys.postgresql.org
2017-06-30Fix locking in WAL receiver/sender shmem state structsAlvaro Herrera
In WAL receiver and WAL server, some accesses to their corresponding shared memory control structs were done without holding any kind of lock, which could lead to inconsistent and possibly insecure results. In walsender, fix by clarifying the locking rules and following them correctly, as documented in the new comment in walsender_private.h; namely that some members can be read in walsender itself without a lock, because the only writes occur in the same process. The rest of the struct requires spinlock for accesses, as usual. In walreceiver, fix by always holding spinlock while accessing the struct. While there is potentially a problem in all branches, it is minor in stable ones. This only became a real problem in pg10 because of quorum commit in synchronous replication (commit 3901fd70cc7c), and a potential security problem in walreceiver because a superuser() check was removed by default monitoring roles (commit 25fff40798fc). Thus, no backpatch. In passing, clean up some leftover braces which were used to create unconditional blocks. Once upon a time these were used for volatile-izing accesses to those shmem structs, which is no longer required. Many other occurrences of this pattern remain. Author: Michaël Paquier Reported-by: Michaël Paquier Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi, Thomas Munro, Robert Haas Discussion: https://postgr.es/m/CAB7nPqTWYqtzD=LN_oDaf9r-hAjUEPAy0B9yRkhcsLdRN8fzrw@mail.gmail.com
2017-06-21Phase 3 of pgindent updates.Tom Lane
Don't move parenthesized lines to the left, even if that means they flow past the right margin. By default, BSD indent lines up statement continuation lines that are within parentheses so that they start just to the right of the preceding left parenthesis. However, traditionally, if that resulted in the continuation line extending to the right of the desired right margin, then indent would push it left just far enough to not overrun the margin, if it could do so without making the continuation line start to the left of the current statement indent. That makes for a weird mix of indentations unless one has been completely rigid about never violating the 80-column limit. This behavior has been pretty universally panned by Postgres developers. Hence, disable it with indent's new -lpl switch, so that parenthesized lines are always lined up with the preceding left paren. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2017-06-21Phase 2 of pgindent updates.Tom Lane
Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/[email protected] Discussion: https://postgr.es/m/[email protected]
2017-05-17Post-PG 10 beta1 pgindent runBruce Momjian
perltidy run not included.
2017-04-25Set the priorities of all quorum synchronous standbys to 1.Fujii Masao
In quorum-based synchronous replication, all the standbys listed in synchronous_standby_names equally have chances to be chosen as synchronous standbys. So they should have the same priority. However, previously, quorum standbys whose names appear earlier in the list were given higher priority values though the difference of those priority values didn't affect the selection of synchronous standbys. Users could see those "meaningless" priority values in pg_stat_replication and this was confusing. This commit gives all the quorum synchronous standbys the same highest priority, i.e., 1, in order to remove such confusion. Author: Fujii Masao Reviewed-by: Masahiko Sawada, Kyotaro Horiguchi Discussion: http://postgr.es/m/CAHGQGwEKOw=SmPLxJzkBsH6wwDBgOnVz46QjHbtsiZ-d-2RGUg@mail.gmail.com
2017-04-18Improve documentation and comment for quorum-based sync replication.Fujii Masao
Author: Masahiko Sawada, heavily modified by me Discussion: http://postgr.es/m/CAHGQGwEKOw=SmPLxJzkBsH6wwDBgOnVz46QjHbtsiZ-d-2RGUg@mail.gmail.com
2017-01-03Update copyright via script for 2017Bruce Momjian
2016-12-19Support quorum-based synchronous replication.Fujii Masao
This feature is also known as "quorum commit" especially in discussion on pgsql-hackers. This commit adds the following new syntaxes into synchronous_standby_names GUC. By using FIRST and ANY keywords, users can specify the method to choose synchronous standbys from the listed servers. FIRST num_sync (standby_name [, ...]) ANY num_sync (standby_name [, ...]) The keyword FIRST specifies a priority-based synchronous replication which was available also in 9.6 or before. This method makes transaction commits wait until their WAL records are replicated to num_sync synchronous standbys chosen based on their priorities. The keyword ANY specifies a quorum-based synchronous replication and makes transaction commits wait until their WAL records are replicated to *at least* num_sync listed standbys. In this method, the values of sync_state.pg_stat_replication for the listed standbys are reported as "quorum". The priority is still assigned to each standby, but not used in this method. The existing syntaxes having neither FIRST nor ANY keyword are still supported. They are the same as new syntax with FIRST keyword, i.e., a priorirty-based synchronous replication. Author: Masahiko Sawada Reviewed-By: Michael Paquier, Amit Kapila and me Discussion: <CAD21AoAACi9NeC_ecm+Vahm+MMA6nYh=Kqs3KB3np+MBOS_gZg@mail.gmail.com> Many thanks to the various individuals who were involved in discussing and developing this feature.
2016-12-16Ensure that num_sync is greater than zero in synchronous_standby_names.Fujii Masao
Previously num_sync could be set to zero and this setting caused an assertion failure. This means that multiple synchronous standbys code should assume that num_sync is greater than zero. Also setting num_sync to zero is nonsense because it's basically the configuration for synchronous replication. If users want not to make transaction commits wait for any standbys, synchronous_standby_names should be emptied to disable synchronous replication instead of setting num_sync to zero. This patch forbids users from setting num_sync to zero in synchronous_standby_names. If zero is specified, an error will happen during processing the parameter settings. Back-patch to 9.6 where multiple synchronous standbys feature was added. Patch by me. Reviewed by Tom Lane. Discussion: <CAHGQGwHWB3izc6cXuFLh5kOcAbFXaRhhgwd-X5PeN9TEjxqXwg@mail.gmail.com>
2016-10-04Extend framework from commit 53be0b1ad to report latch waits.Robert Haas
WaitLatch, WaitLatchOrSocket, and WaitEventSetWait now taken an additional wait_event_info parameter; legal values are defined in pgstat.h. This makes it possible to uniquely identify every point in the core code where we are waiting for a latch; extensions can pass WAIT_EXTENSION. Because latches were the major wait primitive not previously covered by this patch, it is now possible to see information in pg_stat_activity on a large number of important wait events not previously addressed, such as ClientRead, ClientWrite, and SyncRep. Unfortunately, many of the wait events added by this patch will fail to appear in pg_stat_activity because they're only used in background processes which don't currently appear in pg_stat_activity. We should fix this either by creating a separate view for such information, or else by deciding to include them in pg_stat_activity after all. Michael Paquier and Robert Haas, reviewed by Alexander Korotkov and Thomas Munro.
2016-08-15Final pgindent + perltidy run for 9.6.Tom Lane
2016-08-12Code cleanup in SyncRepWaitForLSN()Simon Riggs
Commit 14e8803f1 removed LWLocks when accessing MyProc->syncRepState but didn't clean up the surrounding code and comments. Cleanup and backpatch to 9.5, to keep code similar. Julien Rouhaud, improved by suggestion from Michael Paquier, implemented trivially by myself.
2016-06-09pgindent run for 9.6Robert Haas
2016-04-30Remove warning about num_sync being too large in synchronous_standby_names.Tom Lane
If we're not going to reject such setups entirely, throwing a WARNING in check_synchronous_standby_names() is unhelpful, because it will cause the warning to be logged again every time the postmaster receives SIGHUP. Per discussion, just remove the warning. In passing, improve the documentation for synchronous_commit, which had not gotten the word that now there can be more than one synchronous standby.