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* Use more consistently int64 for page numbers in SLRU-related codeMichael Paquier2024-07-23
| | | | | | | | | | | | | | clog.c, async.c and predicate.c included some SLRU page numbers still handled as 4-byte integers, while int64 should be used for this purpose. These holes have been introduced in 4ed8f0913bfd, that has introduced the use of 8-byte integers for SLRU page numbers, still forgot about the code paths updated by this commit. Reported-by: Noah Misch Author: Aleksander Alekseev, Michael Paquier Discussion: https://postgr.es/m/20240626002747.dc.nmisch@google.com Backpatch-through: 17
* Replace BackendIds with 0-based ProcNumbersHeikki Linnakangas2024-03-03
| | | | | | | | | | | | | | | | | | Now that BackendId was just another index into the proc array, it was redundant with the 0-based proc numbers used in other places. Replace all usage of backend IDs with proc numbers. The only place where the term "backend id" remains is in a few pgstat functions that expose backend IDs at the SQL level. Those IDs are now in fact 0-based ProcNumbers too, but the documentation still calls them "backend ids". That term still seems appropriate to describe what the numbers are, so I let it be. One user-visible effect is that pg_temp_0 is now a valid temp schema name, for backend with ProcNumber 0. Reviewed-by: Andres Freund Discussion: https://www.postgresql.org/message-id/8171f1aa-496f-46a6-afc3-c46fe7a9b407@iki.fi
* Improve performance of subsystems on top of SLRUAlvaro Herrera2024-02-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | More precisely, what we do here is make the SLRU cache sizes configurable with new GUCs, so that sites with high concurrency and big ranges of transactions in flight (resp. multixacts/subtransactions) can benefit from bigger caches. In order for this to work with good performance, two additional changes are made: 1. the cache is divided in "banks" (to borrow terminology from CPU caches), and algorithms such as eviction buffer search only affect one specific bank. This forestalls the problem that linear searching for a specific buffer across the whole cache takes too long: we only have to search the specific bank, whose size is small. This work is authored by Andrey Borodin. 2. Change the locking regime for the SLRU banks, so that each bank uses a separate LWLock. This allows for increased scalability. This work is authored by Dilip Kumar. (A part of this was previously committed as d172b717c6f4.) Special care is taken so that the algorithms that can potentially traverse more than one bank release one bank's lock before acquiring the next. This should happen rarely, but particularly clog.c's group commit feature needed code adjustment to cope with this. I (Álvaro) also added lots of comments to make sure the design is sound. The new GUCs match the names introduced by bcdfa5f2e2f2 in the pg_stat_slru view. The default values for these parameters are similar to the previous sizes of each SLRU. commit_ts, clog and subtrans accept value 0, which means to adjust by dividing shared_buffers by 512 (so 2MB for every 1GB of shared_buffers), with a cap of 8MB. (A new slru.c function SimpleLruAutotuneBuffers() was added to support this.) The cap was previously 1MB for clog, so for sites with more than 512MB of shared memory the total memory used increases, which is likely a good tradeoff. However, other SLRUs (notably multixact ones) retain smaller sizes and don't support a configured value of 0. These values based on shared_buffers may need to be revisited, but that's an easy change. There was some resistance to adding these new GUCs: it would be better to adjust to memory pressure automatically somehow, for example by stealing memory from shared_buffers (where the caches can grow and shrink naturally). However, doing that seems to be a much larger project and one which has made virtually no progress in several years, and because this is such a pain point for so many users, here we take the pragmatic approach. Author: Andrey Borodin <x4mmm@yandex-team.ru> Author: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Amul Sul, Gilles Darold, Anastasia Lubennikova, Ivan Lazarev, Robert Haas, Thomas Munro, Tomas Vondra, Yura Sokolov, Васильев Дмитрий (Dmitry Vasiliev). Discussion: https://postgr.es/m/2BEC2B3F-9B61-4C1D-9FB5-5FAB0F05EF86@yandex-team.ru Discussion: https://postgr.es/m/CAFiTN-vzDvNz=ExGXz6gdyjtzGixKSqs0mKHMmaQ8sOSEFZ33A@mail.gmail.com
* Rename SLRU elements in view pg_stat_slruAlvaro Herrera2024-02-28
| | | | | | | | | | | | | | The new names are intended to match those in an upcoming patch that adds a few GUCs to configure the SLRU buffer sizes. Backwards compatibility concern: this changes the accepted names for function pg_stat_slru_rest(). Since this function recognizes "any other string" as a request to reset the entry for "other", this means that calling it with the old names would silently reset "other" instead of doing nothing or throwing an error. Reviewed-by: Andrey M. Borodin <x4mmm@yandex-team.ru> Discussion: https://postgr.es/m/202402261616.dlriae7b6emv@alvherre.pgsql
* Remove superfluous 'pgprocno' field from PGPROCHeikki Linnakangas2024-02-22
| | | | | | | | | It was always just the index of the PGPROC entry from the beginning of the proc array. Introduce a macro to compute it from the pointer instead. Reviewed-by: Andres Freund Discussion: https://www.postgresql.org/message-id/8171f1aa-496f-46a6-afc3-c46fe7a9b407@iki.fi
* Use atomic access for SlruShared->latest_page_numberAlvaro Herrera2024-02-06
| | | | | | | | | | | The new concurrency model proposed for slru.c to improve performance does not include any single lock that would coordinate processes doing concurrent reads/writes on SlruShared->latest_page_number. We can instead use atomic reads and writes for that variable. Author: Dilip Kumar <dilipbalaut@gmail.com> Reviewed-by: Andrey M. Borodin <x4mmm@yandex-team.ru> Discussion: https://postgr.es/m/CAFiTN-vzDvNz=ExGXz6gdyjtzGixKSqs0mKHMmaQ8sOSEFZ33A@mail.gmail.com
* Update copyright for 2024Bruce Momjian2024-01-03
| | | | | | | | Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
* Rename ShmemVariableCache to TransamVariablesHeikki Linnakangas2023-12-08
| | | | | | | | The old name was misleading: It's not a cache, the values kept in the struct are the authoritative source. Reviewed-by: Tristan Partin, Richard Guo Discussion: https://www.postgresql.org/message-id/6537d63d-4bb5-46f8-9b5d-73a8ba4720ab@iki.fi
* Index SLRUs by 64-bit integers rather than by 32-bit integersAlexander Korotkov2023-11-29
| | | | | | | | | | | | | | | | | | We've had repeated bugs in the area of handling SLRU wraparound in the past, some of which have caused data loss. Switching to an indexing system for SLRUs that does not wrap around should allow us to get rid of a whole bunch of problems and improve the overall reliability of the system. This particular patch however only changes the indexing and doesn't address the wraparound per se. This is going to be done in the following patches. Author: Maxim Orlov, Aleksander Alekseev, Alexander Korotkov, Teodor Sigaev Author: Nikita Glukhov, Pavel Borisov, Yura Sokolov Reviewed-by: Jacob Champion, Heikki Linnakangas, Alexander Korotkov Reviewed-by: Japin Li, Pavel Borisov, Tom Lane, Peter Eisentraut, Andres Freund Reviewed-by: Andrey Borodin, Dilip Kumar, Aleksander Alekseev Discussion: https://postgr.es/m/CACG%3DezZe1NQSCnfHOr78AtAZxJZeCvxrts0ygrxYwe%3DpyyjVWA%40mail.gmail.com Discussion: https://postgr.es/m/CAJ7c6TPDOYBYrnCAeyndkBktO0WG2xSdYduTF0nxq%2BvfkmTF5Q%40mail.gmail.com
* Update copyright for 2023Bruce Momjian2023-01-02
| | | | Backpatch-through: 11
* Static assertions cleanupPeter Eisentraut2022-12-15
| | | | | | | | | | | | | | | | | | | | | Because we added StaticAssertStmt() first before StaticAssertDecl(), some uses as well as the instructions in c.h are now a bit backwards from the "native" way static assertions are meant to be used in C. This updates the guidance and moves some static assertions to better places. Specifically, since the addition of StaticAssertDecl(), we can put static assertions at the file level. This moves a number of static assertions out of function bodies, where they might have been stuck out of necessity, to perhaps better places at the file level or in header files. Also, when the static assertion appears in a position where a declaration is allowed, then using StaticAssertDecl() is more native than StaticAssertStmt(). Reviewed-by: John Naylor <john.naylor@enterprisedb.com> Discussion: https://www.postgresql.org/message-id/flat/941a04e7-dd6f-c0e4-8cdf-a33b3338cbda%40enterprisedb.com
* Update outdated comment for TransactionIdSetTreeStatusHeikki Linnakangas2022-10-25
| | | | | | | | | Commit 06da3c570f changed the way subtransactions are marked as SUBCOMMITTED, but the example it included actually documented the old way. Update it. Author: Japin Li Discussion: https://www.postgresql.org/message-id/MEYP282MB16690BC96DFBE08CC857E1E3B6319%40MEYP282MB1669.AUSP282.PROD.OUTLOOK.COM
* Rename shadowed local variablesDavid Rowley2022-10-05
| | | | | | | | | | | | In a similar effort to f01592f91, here we mostly rename shadowed local variables to remove the warnings produced when compiling with -Wshadow=compatible-local. This fixes 63 warnings and leaves just 5. Author: Justin Pryzby, David Rowley Reviewed-by: Justin Pryzby Discussion https://postgr.es/m/20220817145434.GC26426%40telsasoft.com
* Clean up assorted failures under clang's -fsanitize=undefined checks.Tom Lane2022-03-03
| | | | | | | | | | | | | | | | | | | | | | Most of these are cases where we could call memcpy() or other libc functions with a NULL pointer and a zero count, which is forbidden by POSIX even though every production version of libc allows it. We've fixed such things before in a piecemeal way, but apparently never made an effort to try to get them all. I don't claim that this patch does so either, but it gets every failure I observe in check-world, using clang 12.0.1 on current RHEL8. numeric.c has a different issue that the sanitizer doesn't like: "ln(-1.0)" will compute log10(0) and then try to assign the resulting -Inf to an integer variable. We don't actually use the result in such a case, so there's no live bug. Back-patch to all supported branches, with the idea that we might start running a buildfarm member that tests this case. This includes back-patching c1132aae3 (Check the size in COPY_POINTER_FIELD), which previously silenced some of these issues in copyfuncs.c. Discussion: https://postgr.es/m/CALNJ-vT9r0DSsAOw9OXVJFxLENoVS_68kJ5x0p44atoYH+H4dg@mail.gmail.com
* Update copyright for 2022Bruce Momjian2022-01-07
| | | | Backpatch-through: 10
* Fix race condition in TransactionGroupUpdateXidStatus().Amit Kapila2021-06-28
| | | | | | | | | | | | | | | | | | | When we cannot immediately acquire XactSLRULock in exclusive mode at commit time, we add ourselves to a list of processes that need their XIDs status update. We do this if the clog page where we need to update the current transaction status is the same as the group leader's clog page, otherwise, we allow the caller to clear it by itself. Now, when we can't add ourselves to any group, we were not clearing the current proc if it has already become a member of some group which was leading to an assertion failure when the same proc was assigned to another backend after the current backend exits. Reported-by: Alexander Lakhin Bug: 17072 Author: Amit Kapila Tested-By: Alexander Lakhin Backpatch-through: 11, where it was introduced Discussion: https://postgr.es/m/17072-2f8764857ef2c92a@postgresql.org
* In TrimCLOG(), don't reset XactCtl->shared->latest_page_number.Robert Haas2021-01-27
| | | | | | | | | | | | | | | | | | | | | Since the CLOG page number is not recorded directly in the checkpoint record, we have to use ShmemVariableCache->nextXid to figure out the latest CLOG page number at the start of recovery. However, as recovery progresses, replay of CLOG/EXTEND records will update our notion of the latest page number, and we should rely on that being accurate rather than recomputing the value based on an updated notion of nextXid. ShmemVariableCache->nextXid is only an approximation during recovery anyway, whereas CLOG/EXTEND records are an authoritative representation of how the SLRU has been updated. Commit 0fcc2decd485a61321a3220d8f76cb108b082009 makes this simplification possible, as before that change clog_redo() might have injected a bogus value here, and we'd want to get rid of that before entering normal running. Patch by me, reviewed by Heikki Linnakangas. Discussion: http://postgr.es/m/CA+TgmoZYig9+AQodhF5sRXuKkJ=RgFDugLr3XX_dz_F-p=TwTg@mail.gmail.com
* In clog_redo(), don't set XactCtl->shared->latest_page_number.Robert Haas2021-01-27
| | | | | | | | | | | | | | | | | | | | | | The comment is no longer accurate, and hasn't been entirely accurate since Hot Standby was introduced. The original idea here was that StartupCLOG() wouldn't be called until the end of recovery and therefore this value would be uninitialized when this code is reached, but Hot Standby made that true only when hot_standby=off, and commit 1f113abdf87cd085dee3927960bb4f70442b7250 means that this value is now always initialized before replay even starts. The original purpose of this code was to bypass the sanity check in SimpleLruTruncate(), which will no longer occur: now, if something is wrong, that sanity check might trip during recovery. That's probably a good thing, because in the current code base latest_page_number should always be initialized and therefore we expect that the sanity check should pass. If it doesn't, something has gone wrong, and complaining about it is appropriate. Patch by me, reviewed by Heikki Linnakangas. Discussion: http://postgr.es/m/CA+TgmoZYig9+AQodhF5sRXuKkJ=RgFDugLr3XX_dz_F-p=TwTg@mail.gmail.com
* Prevent excess SimpleLruTruncate() deletion.Noah Misch2021-01-16
| | | | | | | | | | | | | | | | | Every core SLRU wraps around. With the exception of pg_notify, the wrap point can fall in the middle of a page. Account for this in the PagePrecedes callback specification and in SimpleLruTruncate()'s use of said callback. Update each callback implementation to fit the new specification. This changes SerialPagePrecedesLogically() from the style of asyncQueuePagePrecedes() to the style of CLOGPagePrecedes(). (Whereas pg_clog and pg_serial share a key space, pg_serial is nothing like pg_notify.) The bug fixed here has the same symptoms and user followup steps as 592a589a04bd456410b853d86bd05faa9432cbbb. Back-patch to 9.5 (all supported versions). Reviewed by Andrey Borodin and (in earlier versions) by Tom Lane. Discussion: https://postgr.es/m/20190202083822.GC32531@gust.leadboat.com
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Defer flushing of SLRU files.Thomas Munro2020-09-25
| | | | | | | | | | | | | | | | | | | | | | | | Previously, we called fsync() after writing out individual pg_xact, pg_multixact and pg_commit_ts pages due to cache pressure, leading to regular I/O stalls in user backends and recovery. Collapse requests for the same file into a single system call as part of the next checkpoint, as we already did for relation files, using the infrastructure developed by commit 3eb77eba. This can cause a significant improvement to recovery performance, especially when it's otherwise CPU-bound. Hoist ProcessSyncRequests() up into CheckPointGuts() to make it clearer that it applies to all the SLRU mini-buffer-pools as well as the main buffer pool. Rearrange things so that data collected in CheckpointStats includes SLRU activity. Also remove the Shutdown{CLOG,CommitTS,SUBTRANS,MultiXact}() functions, because they were redundant after the shutdown checkpoint that immediately precedes them. (I'm not sure if they were ever needed, but they aren't now.) Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> (parts) Tested-by: Jakub Wartak <Jakub.Wartak@tomtom.com> Discussion: https://postgr.es/m/CA+hUKGLJ=84YT+NvhkEEDAuUtVHMfQ9i-N7k_o50JmQ6Rpj_OQ@mail.gmail.com
* Fix missing fsync of SLRU directories.Thomas Munro2020-09-24
| | | | | | | | | | | | | Harmonize behavior by moving reponsibility for fsyncing directories down into slru.c. In 10 and later, only the multixact directories were missed (see commit 1b02be21), and in older branches all SLRUs were missed. Back-patch to all supported releases. Reviewed-by: Andres Freund <andres@anarazel.de> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://postgr.es/m/CA%2BhUKGLtsTUOScnNoSMZ-2ZLv%2BwGh01J6kAo_DM8mTRq1sKdSQ%40mail.gmail.com
* snapshot scalability: Move subxact info to ProcGlobal, remove PGXACT.Andres Freund2020-08-14
| | | | | | | | | | | | | | | | | | | | Similar to the previous changes this increases the chance that data frequently needed by GetSnapshotData() stays in l2 cache. In many workloads subtransactions are very rare, and this makes the check for that considerably cheaper. As this removes the last member of PGXACT, there is no need to keep it around anymore. On a larger 2 socket machine this and the two preceding commits result in a ~1.07x performance increase in read-only pgbench. For read-heavy mixed r/w workloads without row level contention, I see about 1.1x. 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
* snapshot scalability: Introduce dense array of in-progress xids.Andres Freund2020-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new array contains the xids for all connected backends / in-use PGPROC entries in a dense manner (in contrast to the PGPROC/PGXACT arrays which can have unused entries interspersed). This improves performance because GetSnapshotData() always needs to scan the xids of all live procarray entries and now there's no need to go through the procArray->pgprocnos indirection anymore. As the set of running top-level xids changes rarely, compared to the number of snapshots taken, this substantially increases the likelihood of most data required for a snapshot being in l2 cache. In read-mostly workloads scanning the xids[] array will sufficient to build a snapshot, as most backends will not have an xid assigned. To keep the xid array dense ProcArrayRemove() needs to move entries behind the to-be-removed proc's one further up in the array. Obviously moving array entries cannot happen while a backend sets it xid. I.e. locking needs to prevent that array entries are moved while a backend modifies its xid. To avoid locking ProcArrayLock in GetNewTransactionId() - a fairly hot spot already - ProcArrayAdd() / ProcArrayRemove() now needs to hold XidGenLock in addition to ProcArrayLock. Adding / Removing a procarray entry is not a very frequent operation, even taking 2PC into account. Due to the above, the dense array entries can only be read or modified while holding ProcArrayLock and/or XidGenLock. This prevents a concurrent ProcArrayRemove() from shifting the dense array while it is accessed concurrently. While the new dense array is very good when needing to look at all xids it is less suitable when accessing a single backend's xid. In particular it would be problematic to have to acquire a lock to access a backend's own xid. Therefore a backend's xid is not just stored in the dense array, but also in PGPROC. This also allows a backend to only access the shared xid value when the backend had acquired an xid. The infrastructure added in this commit will be used for the remaining PGXACT fields in subsequent commits. They are kept separate to make review easier. 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
* Rename VariableCacheData.nextFullXid to nextXid.Andres Freund2020-08-11
| | | | | | | | | Including Full in variable names duplicates the type information and leads to overly long names. As FullTransactionId cannot accidentally be casted to TransactionId that does not seem necessary. Author: Andres Freund Discussion: https://postgr.es/m/20200724011143.jccsyvsvymuiqfxu@alap3.anarazel.de
* Mop-up for wait event naming issues.Tom Lane2020-05-16
| | | | | | | | | | | | Synchronize the event names for parallel hash join waits with other event names, by getting rid of the slashes and dropping "-ing" suffixes. Rename ClogGroupUpdate to XactGroupUpdate, to match the new SLRU name. Move the ProcSignalBarrier event to the IPC category; it doesn't belong under IO. Also a bit more wordsmithing in the wait event documentation tables. Discussion: https://postgr.es/m/4505.1589640417@sss.pgh.pa.us
* Rename SLRU structures and associated LWLocks.Tom Lane2020-05-15
| | | | | | | | | | | | | | | | | | | | | | | | | | Originally, the names assigned to SLRUs had no purpose other than being shmem lookup keys, so not a lot of thought went into them. As of v13, though, we're exposing them in the pg_stat_slru view and the pg_stat_reset_slru function, so it seems advisable to take a bit more care. Rename them to names based on the associated on-disk storage directories (which fortunately we *did* think about, to some extent; since those are also visible to DBAs, consistency seems like a good thing). Also rename the associated LWLocks, since those names are likewise user-exposed now as wait event names. For the most part I only touched symbols used in the respective modules' SimpleLruInit() calls, not the names of other related objects. This renaming could have been taken further, and maybe someday we will do so. But for now it seems undesirable to change the names of any globally visible functions or structs, so some inconsistency is unavoidable. (But I *did* terminate "oldserxid" with prejudice, as I found that name both unreadable and not descriptive of the SLRU's contents.) Table 27.12 needs re-alphabetization now, but I'll leave that till after the other LWLock renamings I have in mind. Discussion: https://postgr.es/m/28683.1589405363@sss.pgh.pa.us
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Change overly strict Assert in TransactionGroupUpdateXidStatus.Amit Kapila2019-12-17
| | | | | | | | | | | | | | | | | | This Assert thought that an overflowed transaction can never get registered for the group update.  But that is not true, because even when the number of children for a transaction got reduced, the overflow flag is not changed. And, for group update, we only care about the current number of children for a transaction that is being committed. Based on comments by Andres Freund, remove a redundant Assert in TransactionIdSetPageStatus as we already had a static Assert for the same condition a few lines earlier. Reported-by: Vignesh C Author: Dilip Kumar Reviewed-by: Amit Kapila Backpatch-through: 11 Discussion: https://postgr.es/m/CAFiTN-s5=uJw-Z6JC9gcqtBSjXsrHnU63PXBrA=pnBjqnkm5UA@mail.gmail.com
* Make the order of the header file includes consistent in backend modules.Amit Kapila2019-11-12
| | | | | | | | | | | Similar to commits 7e735035f2 and dddf4cdc33, this commit makes the order of header file inclusion consistent for backend modules. In the passing, removed a couple of duplicate inclusions. Author: Vignesh C Reviewed-by: Kuntal Ghosh and Amit Kapila Discussion: https://postgr.es/m/CALDaNm2Sznv8RR6Ex-iJO6xAdsxgWhCoETkaYX=+9DW3q0QCfA@mail.gmail.com
* Fix inconsistencies and typos in the tree, take 9Michael Paquier2019-08-05
| | | | | | | | This addresses more issues with code comments, variable names and unreferenced variables. Author: Alexander Lakhin Discussion: https://postgr.es/m/7ab243e0-116d-3e44-d120-76b3df7abefd@gmail.com
* Fix inconsistencies and typos in the treeMichael Paquier2019-07-22
| | | | | | | | This is numbered take 7, and addresses a set of issues with code comments, variable names and unreferenced variables. Author: Alexander Lakhin Discussion: https://postgr.es/m/dff75442-2468-f74f-568c-6006e141062f@gmail.com
* Fix inconsistencies and typos in the treeMichael Paquier2019-07-16
| | | | | | | | | | | This is numbered take 7, and addresses a set of issues around: - Fixes for typos and incorrect reference names. - Removal of unneeded comments. - Removal of unreferenced functions and structures. - Fixes regarding variable name consistency. Author: Alexander Lakhin Discussion: https://postgr.es/m/10bfd4ac-3e7c-40ab-2b2e-355ed15495e8@gmail.com
* Phase 2 pgindent run for v12.Tom Lane2019-05-22
| | | | | | | | | 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
* Add basic infrastructure for 64 bit transaction IDs.Thomas Munro2019-03-28
| | | | | | | | | | | | | | | | | | | | | | | | Instead of inferring epoch progress from xids and checkpoints, introduce a 64 bit FullTransactionId type and use it to track xid generation. This fixes an unlikely bug where the epoch is reported incorrectly if the range of active xids wraps around more than once between checkpoints. The only user-visible effect of this commit is to correct the epoch used by txid_current() and txid_status(), also visible with pg_controldata, in those rare circumstances. It also creates some basic infrastructure so that later patches can use 64 bit transaction IDs in more places. The new type is a struct that we pass by value, as a form of strong typedef. This prevents the sort of accidental confusion between TransactionId and FullTransactionId that would be possible if we were to use a plain old uint64. Author: Thomas Munro Reported-by: Amit Kapila Reviewed-by: Andres Freund, Tom Lane, Heikki Linnakangas Discussion: https://postgr.es/m/CAA4eK1%2BMv%2Bmb0HFfWM9Srtc6MVe160WFurXV68iAFMcagRZ0dQ%40mail.gmail.com
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Change TRUE/FALSE to true/falsePeter Eisentraut2017-11-08
| | | | | | | | | | | | | | The lower case spellings are C and C++ standard and are used in most parts of the PostgreSQL sources. The upper case spellings are only used in some files/modules. So standardize on the standard spellings. The APIs for ICU, Perl, and Windows define their own TRUE and FALSE, so those are left as is when using those APIs. In code comments, we use the lower-case spelling for the C concepts and keep the upper-case spelling for the SQL concepts. Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
* Fix access-off-end-of-array in clog.c.Tom Lane2017-10-06
| | | | | | | | | | | | | Sloppy loop coding in set_status_by_pages() resulted in fetching one array element more than it should from the subxids[] array. The odds of this resulting in SIGSEGV are pretty small, but we've certainly seen that happen with similar mistakes elsewhere. While at it, we can get rid of an extra TransactionIdToPage() calculation per loop. Per report from David Binderman. Back-patch to all supported branches, since this code is quite old. Discussion: https://postgr.es/m/HE1PR0802MB2331CBA919CBFFF0C465EB429C710@HE1PR0802MB2331.eurprd08.prod.outlook.com
* Use group updates when setting transaction status in clog.Robert Haas2017-09-01
| | | | | | | | | | | | | | | Commit 0e141c0fbb211bdd23783afa731e3eef95c9ad7a introduced a mechanism to reduce contention on ProcArrayLock by having a single process clear XIDs in the procArray on behalf of multiple processes, reducing the need to hand the lock around. A previous attempt to introduce a similar mechanism for CLogControlLock in ccce90b398673d55b0387b3de66639b1b30d451b crashed and burned, but the design problem which resulted in those failures is believed to have been corrected in this version. Amit Kapila, with some cosmetic changes by me. See the previous commit message for additional credits. Discussion: http://postgr.es/m/CAA4eK1KudxzgWhuywY_X=yeSAhJMT4DwCjroV5Ay60xaeB2Eew@mail.gmail.com
* Remove incorrect assertion in clog.cRobert Haas2017-08-10
| | | | | | | | | | | We must advance the oldest XID that can be safely looked up in clog *before* truncating CLOG, and the oldest XID that can't be reused *after* truncating CLOG. This assertion, and the accompanying comment, are confused; remove them. Reported by Neha Sharma. Discussion: http://postgr.es/m/CANiYTQumC3T=UMBMd1Hor=5XWZYuCEQBioL3ug0YtNQCMMT5wQ@mail.gmail.com
* Phase 3 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | 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/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Phase 2 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Post-PG 10 beta1 pgindent runBruce Momjian2017-05-17
| | | | perltidy run not included.
* Fsync directory after creating or unlinking file.Teodor Sigaev2017-03-27
| | | | | | | | | If file was created/deleted just before powerloss it's possible that file system will miss that. To prevent it, call fsync() where creating/ unlinkg file is critical. Author: Michael Paquier Reviewed-by: Ashutosh Bapat, Takayuki Tsunakawa, me
* Track the oldest XID that can be safely looked up in CLOG.Robert Haas2017-03-23
| | | | | | | | | | | | | | This provides infrastructure for looking up arbitrary, user-supplied XIDs without a risk of scary-looking failures from within the clog module. Normally, the oldest XID that can be safely looked up in CLOG is the same as the oldest XID that can reused without causing wraparound, and the latter is already tracked. However, while truncation is in progress, the values are different, so we must keep track of them separately. Craig Ringer, reviewed by Simon Riggs and by me. Discussion: http://postgr.es/m/CAMsr+YHQiWNEi0daCTboS40T+V5s_+dst3PYv_8v2wNVH+Xx4g@mail.gmail.com
* Rename "pg_clog" directory to "pg_xact".Robert Haas2017-03-17
| | | | | | | | | | | Names containing the letters "log" sometimes confuse users into believing that only non-critical data is present. It is hoped this renaming will discourage ill-considered removals of transaction status data. Michael Paquier Discussion: http://postgr.es/m/CA+Tgmoa9xFQyjRZupbdEFuwUerFTvC6HjZq1ud6GYragGDFFgA@mail.gmail.com
* Revert "Use group updates when setting transaction status in clog."Robert Haas2017-03-10
| | | | | | | | This reverts commit ccce90b398673d55b0387b3de66639b1b30d451b. This optimization is unsafe, at least, of rollbacks and rollbacks to savepoints, but I'm concerned there may be other problematic cases as well. Therefore, I've decided to revert this pending further investigation.
* Use group updates when setting transaction status in clog.Robert Haas2017-03-09
| | | | | | | | | | | | | | | | | | | | | | Commit 0e141c0fbb211bdd23783afa731e3eef95c9ad7a introduced a mechanism to reduce contention on ProcArrayLock by having a single process clear XIDs in the procArray on behalf of multiple processes, reducing the need to hand the lock around. Use a similar mechanism to reduce contention on CLogControlLock. Testing shows that this very significantly reduces the amount of time waiting for CLogControlLock on high-concurrency pgbench tests run on a large multi-socket machines; whether that translates into a TPS improvement depends on how much of that contention is simply shifted to some other lock, particularly WALWriteLock. Amit Kapila, with some cosmetic changes by me. Extensively reviewed, tested, and benchmarked over a period of about 15 months by Simon Riggs, Robert Haas, Andres Freund, Jesper Pedersen, and especially by Tomas Vondra and Dilip Kumar. Discussion: http://postgr.es/m/CAA4eK1L_snxM_JcrzEstNq9P66++F4kKFce=1r5+D1vzPofdtg@mail.gmail.com Discussion: http://postgr.es/m/CAA4eK1LyR2A+m=RBSZ6rcPEwJ=rVi1ADPSndXHZdjn56yqO6Vg@mail.gmail.com Discussion: http://postgr.es/m/91d57161-d3ea-0cc2-6066-80713e4f90d7@2ndquadrant.com
* Update copyright via script for 2017Bruce Momjian2017-01-03
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