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* Add idle_session_timeout.Tom Lane2021-01-06
| | | | | | | | | | | | This GUC variable works much like idle_in_transaction_session_timeout, in that it kills sessions that have waited too long for a new client query. But it applies when we're not in a transaction, rather than when we are. Li Japin, reviewed by David Johnston and Hayato Kuroda, some fixes by me Discussion: https://postgr.es/m/763A0689-F189-459E-946F-F0EC4458980B@hotmail.com
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Fix assorted issues in backend's GSSAPI encryption support.Tom Lane2020-12-28
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Add GSS information to connection authorized log messageStephen Frost2020-12-02
| | | | | | | | | | | | | | | GSS information (if used) such as if the connection was authorized using GSS or if it was encrypted using GSS, and perhaps most importantly, what the GSS principal used for the authentication was, is extremely useful but wasn't being included in the connection authorized log message. Therefore, add to the connection authorized log message that information, in a similar manner to how we log SSL information when SSL is used for a connection. Author: Vignesh C Reviewed-by: Bharath Rupireddy Discussion: https://www.postgresql.org/message-id/CALDaNm2N1385_Ltoo%3DS7VGT-ESu_bRQa-sC1wg6ikrM2L2Z49w%40mail.gmail.com
* Move catalog index declarationsPeter Eisentraut2020-11-07
| | | | | | | | | | | | Move the system catalog index declarations from catalog/indexing.h to the respective parent tables' catalog/pg_*.h files. The original reason for having it split was that the old genbki system produced the output in the order of the catalog files it read, so all the indexing stuff needed to come separately. But this is no longer the case, and keeping it together makes more sense. Reviewed-by: John Naylor <john.naylor@enterprisedb.com> Discussion: https://www.postgresql.org/message-id/flat/c7cc82d6-f976-75d6-2e3e-b03d2cab26bb@2ndquadrant.com
* Centralize setup of SIGQUIT handling for postmaster child processes.Tom Lane2020-09-16
| | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Fix postmaster's behavior during smart shutdown.Tom Lane2020-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* snapshot scalability: Don't compute global horizons while building snapshots.Andres Freund2020-08-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* Use a long lived WaitEventSet for WaitLatch().Thomas Munro2020-07-30
| | | | | | | | | | | | | 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
* Add hash_mem_multiplier GUC.Peter Geoghegan2020-07-29
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Add a GUC that acts as a multiplier on work_mem. It gets applied when sizing executor node hash tables that were previously size constrained using work_mem alone. The new GUC can be used to preferentially give hash-based nodes more memory than the generic work_mem limit. It is intended to enable admin tuning of the executor's memory usage. Overall system throughput and system responsiveness can be improved by giving hash-based executor nodes more memory (especially over sort-based alternatives, which are often much less sensitive to being memory constrained). The default value for hash_mem_multiplier is 1.0, which is also the minimum valid value. This means that hash-based nodes continue to apply work_mem in the traditional way by default. hash_mem_multiplier is generally useful. However, it is being added now due to concerns about hash aggregate performance stability for users that upgrade to Postgres 13 (which added disk-based hash aggregation in commit 1f39bce0). While the old hash aggregate behavior risked out-of-memory errors, it is nevertheless likely that many users actually benefited. Hash agg's previous indifference to work_mem during query execution was not just faster; it also accidentally made aggregation resilient to grouping estimate problems (at least in cases where this didn't create destabilizing memory pressure). hash_mem_multiplier can provide a certain kind of continuity with the behavior of Postgres 12 hash aggregates in cases where the planner incorrectly estimates that all groups (plus related allocations) will fit in work_mem/hash_mem. This seems necessary because hash-based aggregation is usually much slower when only a small fraction of all groups can fit. Even when it isn't possible to totally avoid hash aggregates that spill, giving hash aggregation more memory will reliably improve performance (the same cannot be said for external sort operations, which appear to be almost unaffected by memory availability provided it's at least possible to get a single merge pass). The PostgreSQL 13 release notes should advise users that increasing hash_mem_multiplier can help with performance regressions associated with hash aggregation. That can be taken care of by a later commit. Author: Peter Geoghegan Reviewed-By: Álvaro Herrera, Jeff Davis Discussion: https://postgr.es/m/20200625203629.7m6yvut7eqblgmfo@alap3.anarazel.de Discussion: https://postgr.es/m/CAH2-WzmD%2Bi1pG6rc1%2BCjc4V6EaFJ_qSuKCCHVnH%3DoruqD-zqow%40mail.gmail.com Backpatch: 13-, where disk-based hash aggregation was introduced.
* code: replace 'master' with 'leader' where appropriate.Andres Freund2020-07-08
| | | | | | | | | Leader already is the more widely used terminology, but a few places didn't get the message. Author: Andres Freund Reviewed-By: David Steele Discussion: https://postgr.es/m/20200615182235.x7lch5n6kcjq4aue@alap3.anarazel.de
* Initialize work_mem using current guc.c default.Peter Geoghegan2020-07-02
| | | | | | | Do the same for the maintenance_work_mem global variable. Oversight in commit 848ae330a49, which increased the previous defaults for work_mem and maintenance_work_mem by 4X.
* Initial pgindent and pgperltidy run for v13.Tom Lane2020-05-14
| | | | | | | | | | | Includes some manual cleanup of places that pgindent messed up, most of which weren't per project style anyway. Notably, it seems some people didn't absorb the style rules of commit c9d297751, because there were a bunch of new occurrences of function calls with a newline just after the left paren, all with faulty expectations about how the rest of the call would get indented.
* Recompute stack base in forked postmaster children.Andres Freund2020-04-05
| | | | | | | | | | | This is for the benefit of running postgres under the rr debugger. When using rr signal handlers running while a syscall is active use an alternative stack. As e.g. bgworkers are started from within signal handlers, the forked backend then has a different stack base than postmaster. Previously that subsequently lead to those processes triggering spurious "stack depth limit exceeded" errors. Discussion: https://postgr.es/m/20200327182217.ubrrl32lyfhxfwk5@alap3.anarazel.de
* Unify several ways to tracking backend typePeter Eisentraut2020-03-13
| | | | | | | | | | | | | | Add a new global variable MyBackendType that uses the same BackendType enum that was previously only used by the stats collector. That way several duplicate ways of checking what type a particular process is can be simplified. Since it's no longer just for stats, move to miscinit.c and rename existing functions to match the expanded purpose. Reviewed-by: Julien Rouhaud <rjuju123@gmail.com> Reviewed-by: Kuntal Ghosh <kuntalghosh.2007@gmail.com> Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> Discussion: https://www.postgresql.org/message-id/flat/c65e5196-4f04-4ead-9353-6088c19615a3@2ndquadrant.com
* Refactor ps_status.c APIPeter Eisentraut2020-03-11
| | | | | | | | | | | | | | | | | | | | | | 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 <rjuju123@gmail.com> Reviewed-by: Kuntal Ghosh <kuntalghosh.2007@gmail.com> Reviewed-by: Alvaro Herrera <alvherre@2ndquadrant.com> Discussion: https://www.postgresql.org/message-id/flat/c65e5196-4f04-4ead-9353-6088c19615a3@2ndquadrant.com
* Clean up order in miscinit.c a bitPeter Eisentraut2020-03-11
| | | | | | The code around InitPostmasterChild() from commit 31c453165b5 somehow ended up in the middle of a block of code related to "User ID state". Move it into its own block instead.
* Assume that we have utime() and <utime.h>.Tom Lane2020-02-21
| | | | | | | | | | | | | | | | | | These are required by POSIX since SUSv2, and no live platforms fail to provide them. On Windows, utime() exists and we bring our own <utime.h>, so we're good there too. So remove the configure probes and ad-hoc substitute code. We don't need to check for utimes() anymore either, since that was only used as a substitute. In passing, make the Windows build include <sys/utime.h> only where we need it, not everywhere. This is part of a series of commits to get rid of no-longer-relevant configure checks and dead src/port/ code. I'm committing them separately to make it easier to back out individual changes if they prove less portable than I expect. Discussion: https://postgr.es/m/15379.1582221614@sss.pgh.pa.us
* Use pg_pwrite() in more places.Thomas Munro2020-02-11
| | | | | | | | This removes some lseek() system calls. Author: Thomas Munro Reviewed-by: Andres Freund Discussion: https://postgr.es/m/CA%2BhUKGJ%2BoHhnvqjn3%3DHro7xu-YDR8FPr0FL6LF35kHRX%3D_bUzg%40mail.gmail.com
* Make vacuum buffer counters 64 bits wideAlvaro Herrera2020-02-05
| | | | | | | | | | | | Using 32 bit counters means they can now realistically wrap around when vacuuming extremely large tables. Because they're signed integers, stats printed by vacuum look very odd when they do. We'd love to backpatch this, but refrain because the variables are exported and could cause third-party code to break. Reviewed-by: Julien Rouhaud, Tom Lane, Michael Paquier Discussion: https://postgr.es/m/20200131205926.GA16367@alvherre.pgsql
* Update copyrights for 2020Bruce Momjian2020-01-01
| | | | Backpatch-through: update all files in master, backpatch legal files through 9.4
* Revert "Rename files and headers related to index AM"Michael Paquier2019-12-27
| | | | | | | | This follows multiple complains from Peter Geoghegan, Andres Freund and Alvaro Herrera that this issue ought to be dug more before actually happening, if it happens. Discussion: https://postgr.es/m/20191226144606.GA5659@alvherre.pgsql
* Rename files and headers related to index AMMichael Paquier2019-12-25
| | | | | | | | | | | | | | | | | | | | | The following renaming is done so as source files related to index access methods are more consistent with table access methods (the original names used for index AMs ware too generic, and could be confused as including features related to table AMs): - amapi.h -> indexam.h. - amapi.c -> indexamapi.c. Here we have an equivalent with backend/access/table/tableamapi.c. - amvalidate.c -> indexamvalidate.c. - amvalidate.h -> indexamvalidate.h. - genam.c -> indexgenam.c. - genam.h -> indexgenam.h. This has been discussed during the development of v12 when table AM was worked on, but the renaming never happened. Author: Michael Paquier Reviewed-by: Fabien Coelho, Julien Rouhaud Discussion: https://postgr.es/m/20191223053434.GF34339@paquier.xyz
* Extend the ProcSignal mechanism to support barriers.Robert Haas2019-12-19
| | | | | | | | | | | | | | | | | | | | | | A new function EmitProcSignalBarrier() can be used to emit a global barrier which all backends that participate in the ProcSignal mechanism must absorb, and a new function WaitForProcSignalBarrier() can be used to wait until all relevant backends have in fact absorbed the barrier. This can be used to coordinate global state changes, such as turning checksums on while the system is running. There's no real client of this mechanism yet, although two are proposed, but an enum has to have at least one element, so this includes a placeholder type (PROCSIGNAL_BARRIER_PLACEHOLDER) which should be replaced by the first real client of this mechanism to get committed. Andres Freund and Robert Haas, reviewed by Daniel Gustafsson and, in earlier versions, by Magnus Hagander. Discussion: http://postgr.es/m/CA+TgmoZwDk=BguVDVa+qdA6SBKef=PKbaKDQALTC_9qoz1mJqg@mail.gmail.com
* Partially deduplicate interrupt handling for background processes.Robert Haas2019-12-17
| | | | | | | | | | | | | | | | Where possible, share signal handler code and main loop interrupt checking. This saves quite a bit of code and should simplify maintenance, too. This commit intends not to change the way anything works, even though that might allow more code to be unified. It does unify a bunch of individual variables into a ShutdownRequestPending flag that has is now used by a bunch of different process types, though. Patch by me, reviewed by Andres Freund and Daniel Gustafsson. Discussion: http://postgr.es/m/CA+TgmoZwDk=BguVDVa+qdA6SBKef=PKbaKDQALTC_9qoz1mJqg@mail.gmail.com
* Fix typos in miscinit.c.Amit Kapila2019-12-09
| | | | | | | | | | | Commit f13ea95f9e moved the description of postmaster.pid file contents from miscadmin.h to pidfile.h, but missed to update the comments in miscinit.c. Author: Hadi Moshayedi Reviewed-by: Amit Kapila Backpatch-through: 10 Discussion: https://postgr.es/m/CAK=1=WpYEM9x3LGkaxgXaxeYQjnkdW8XLsxrYRTE2Gq-H83FMw@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
* Split all OBJS style lines in makefiles into one-line-per-entry style.Andres Freund2019-11-05
| | | | | | | | | | | | | | | When maintaining or merging patches, one of the most common sources for conflicts are the list of objects in makefiles. Especially when the split across lines has been changed on both sides, which is somewhat common due to attempting to stay below 80 columns, those conflicts are unnecessarily laborious to resolve. By splitting, and alphabetically sorting, OBJS style lines into one object per line, conflicts should be less frequent, and easier to resolve when they still occur. Author: Andres Freund Discussion: https://postgr.es/m/20191029200901.vww4idgcxv74cwes@alap3.anarazel.de
* Revert hooks for session start and end, take twoMichael Paquier2019-10-02
| | | | | | | | | | | The location of the session end hook has been chosen so as it is possible to allow modules to do their own transactions, however any trying to any any subsystem which went through before_shmem_exit() would cause issues, limiting the pluggability of the hook. Per discussion with Tom Lane and Andres Freund. Discussion: https://postgr.es/m/18722.1569906636@sss.pgh.pa.us
* Add hooks for session start and session end, take twoMichael Paquier2019-10-01
| | | | | | | | | | | | | | | | These hooks can be used in loadable modules. A simple test module is included. The first attempt was done with cd8ce3a but we lacked handling for NO_INSTALLCHECK in the MSVC scripts (problem solved afterwards by 431f1599) so the buildfarm got angry. This also fixes a couple of issues noticed upon review compared to the first attempt, so the code has slightly changed, resulting in a more simple test module. Author: Fabrízio de Royes Mello, Yugo Nagata Reviewed-by: Andrew Dunstan, Michael Paquier, Aleksandr Parfenov Discussion: https://postgr.es/m/20170720204733.40f2b7eb.nagata@sraoss.co.jp Discussion: https://postgr.es/m/20190823042602.GB5275@paquier.xyz
* Use data directory inode number, not port, to select SysV resource keys.Tom Lane2019-09-05
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This approach provides a much tighter binding between a data directory and the associated SysV shared memory block (and SysV or named-POSIX semaphores, if we're using those). Key collisions are still possible, but only between data directories stored on different filesystems, so the situation should be negligible in practice. More importantly, restarting the postmaster with a different port number no longer risks failing to identify a relevant shared memory block, even when postmaster.pid has been removed. A standalone backend is likewise much more certain to detect conflicting leftover backends. (In the longer term, we might now think about deprecating the port as a cluster-wide value, so that one postmaster could support sockets with varying port numbers. But that's for another day.) The hazards fixed here apply only on Unix systems; our Windows code paths already use identifiers derived from the data directory path name rather than the port. src/test/recovery/t/017_shm.pl, which intends to test key-collision cases, has been substantially rewritten since it can no longer use two postmasters with identical port numbers to trigger the case. Instead, use Perl's IPC::SharedMem module to create a conflicting shmem segment directly. The test script will be skipped if that module is not available. (This means that some older buildfarm members won't run it, but I don't think that that results in any meaningful coverage loss.) Patch by me; thanks to Noah Misch and Peter Eisentraut for discussion and review. Discussion: https://postgr.es/m/16908.1557521200@sss.pgh.pa.us
* Represent Lists as expansible arrays, not chains of cons-cells.Tom Lane2019-07-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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/11587.1550975080@sss.pgh.pa.us
* Initial pgindent run for v12.Tom Lane2019-05-22
| | | | | | | | 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/16296.1558103386@sss.pgh.pa.us
* Consistently test for in-use shared memory.Noah Misch2019-04-12
| | | | | | | | | | | | | | | | | | | | | | postmaster startup scrutinizes any shared memory segment recorded in postmaster.pid, exiting if that segment matches the current data directory and has an attached process. When the postmaster.pid file was missing, a starting postmaster used weaker checks. Change to use the same checks in both scenarios. This increases the chance of a startup failure, in lieu of data corruption, if the DBA does "kill -9 `head -n1 postmaster.pid` && rm postmaster.pid && pg_ctl -w start". A postmaster will no longer stop if shmat() of an old segment fails with EACCES. A postmaster will no longer recycle segments pertaining to other data directories. That's good for production, but it's bad for integration tests that crash a postmaster and immediately delete its data directory. Such a test now leaks a segment indefinitely. No "make check-world" test does that. win32_shmem.c already avoided all these problems. In 9.6 and later, enhance PostgresNode to facilitate testing. Back-patch to 9.4 (all supported versions). Reviewed (in earlier versions) by Daniel Gustafsson and Kyotaro HORIGUCHI. Discussion: https://postgr.es/m/20190408064141.GA2016666@rfd.leadboat.com
* Revert "Consistently test for in-use shared memory."Noah Misch2019-04-05
| | | | | | | | | This reverts commits 2f932f71d9f2963bbd201129d7b971c8f5f077fd, 16ee6eaf80a40007a138b60bb5661660058d0422 and 6f0e190056fe441f7cf788ff19b62b13c94f68f3. The buildfarm has revealed several bugs. Back-patch like the original commits. Discussion: https://postgr.es/m/20190404145319.GA1720877@rfd.leadboat.com
* Refactor the fsync queue for wider use.Thomas Munro2019-04-04
| | | | | | | | | | | | | | | | | | | | | | | Previously, md.c and checkpointer.c were tightly integrated so that fsync calls could be handed off and processed in the background. Introduce a system of callbacks and file tags, so that other modules can hand off fsync work in the same way. For now only md.c uses the new interface, but other users are being proposed. Since there may be use cases that are not strictly SMGR implementations, use a new function table for sync handlers rather than extending the traditional SMGR one. Instead of using a bitmapset of segment numbers for each RelFileNode in the checkpointer's hash table, make the segment number part of the key. This requires sending explicit "forget" requests for every segment individually when relations are dropped, but suits the file layout schemes of proposed future users better (ie sparse or high segment numbers). Author: Shawn Debnath and Thomas Munro Reviewed-by: Thomas Munro, Andres Freund Discussion: https://postgr.es/m/CAEepm=2gTANm=e3ARnJT=n0h8hf88wqmaZxk0JYkxw+b21fNrw@mail.gmail.com
* Consistently test for in-use shared memory.Noah Misch2019-04-03
| | | | | | | | | | | | | | | | | | | | | postmaster startup scrutinizes any shared memory segment recorded in postmaster.pid, exiting if that segment matches the current data directory and has an attached process. When the postmaster.pid file was missing, a starting postmaster used weaker checks. Change to use the same checks in both scenarios. This increases the chance of a startup failure, in lieu of data corruption, if the DBA does "kill -9 `head -n1 postmaster.pid` && rm postmaster.pid && pg_ctl -w start". A postmaster will no longer recycle segments pertaining to other data directories. That's good for production, but it's bad for integration tests that crash a postmaster and immediately delete its data directory. Such a test now leaks a segment indefinitely. No "make check-world" test does that. win32_shmem.c already avoided all these problems. In 9.6 and later, enhance PostgresNode to facilitate testing. Back-patch to 9.4 (all supported versions). Reviewed by Daniel Gustafsson and Kyotaro HORIGUCHI. Discussion: https://postgr.es/m/20130911033341.GD225735@tornado.leadboat.com
* Update HINT for pre-existing shared memory block.Noah Misch2019-03-31
| | | | | | | | | | | | One should almost always terminate an old process, not use a manual removal tool like ipcrm. Removal of the ipcclean script eleven years ago (39627b1ae680cba44f6e56ca5facec4fdbfe9495) and its non-replacement corroborate that manual shm removal is now a niche goal. Back-patch to 9.4 (all supported versions). Reviewed by Daniel Gustafsson and Kyotaro HORIGUCHI. Discussion: https://postgr.es/m/20180812064815.GB2301738@rfd.leadboat.com
* tableam: Add and use scan APIs.Andres Freund2019-03-11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
* Revert "Increase the default vacuum_cost_limit from 200 to 2000"Tom Lane2019-03-10
| | | | | | | | | | | | | | This reverts commit bd09503e633b8077822bb4daf91625b71ac16253. Per discussion, it seems like what we should do instead is to reduce the default value of autovacuum_vacuum_cost_delay by the same factor. That's functionally equivalent as long as the platform can accurately service the smaller delay request, which should be true on anything released in the last 10 years or more. And smaller, more-closely-spaced delays are better in terms of providing a steady I/O load. Discussion: https://postgr.es/m/28720.1552101086@sss.pgh.pa.us
* Convert [autovacuum_]vacuum_cost_delay into floating-point GUCs.Tom Lane2019-03-10
| | | | | | | | | | | | | | | | | | | | | This change makes it possible to specify sub-millisecond delays, which work well on most modern platforms, though that was not true when the cost-delay feature was designed. To support this without breaking existing configuration entries, improve guc.c to allow floating-point GUCs to have units. Also, allow "us" (microseconds) as an input/output unit for time-unit GUCs. (It's not allowed as a base unit, at least not yet.) Likewise change the autovacuum_vacuum_cost_delay reloption to be floating-point; this forces a catversion bump because the layout of StdRdOptions changes. This patch doesn't in itself change the default values or allowed ranges for these parameters, and it should not affect the behavior for any already-allowed setting for them. Discussion: https://postgr.es/m/1798.1552165479@sss.pgh.pa.us
* Increase the default vacuum_cost_limit from 200 to 2000Andrew Dunstan2019-03-06
| | | | | | | | | | | | | | | | | | | | | | | | The original 200 default value was set back in f425b605f4e when the cost delay settings were first added. Hardware has improved quite a bit since then and we've also made improvements such as sorting buffers during checkpoints (9cd00c457e6) which should result in less random writes. This low default value was reportedly causing problems with badly configured servers and in the absence of a native method to remove excessive bloat from tables without incurring an AccessExclusiveLock, this often made cleaning up the damage caused by badly configured auto-vacuums difficult. It seems more likely that someone will notice that auto-vacuum is running too quickly than too slowly, so let's go all out and multiple the default value for the setting by 10. With the default vacuum_cost_page_dirty and autovacuum_vacuum_cost_delay (assuming a page size of 8192 bytes), this allows autovacuum a theoretical maximum dirty write rate of around 39MB/s instead of just 3.9MB/s. Author: David Rowley Discussion: https://postgr.es/m/CAKJS1f_YbXC2qTMPyCbmsPiKvZYwpuQNQMohiRXLj1r=8_rYvw@mail.gmail.com
* Move max_wal_senders out of max_connections for connection slot handlingMichael Paquier2019-02-12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since its introduction, max_wal_senders is counted as part of max_connections when it comes to define how many connection slots can be used for replication connections with a WAL sender context. This can lead to confusion for some users, as it could be possible to block a base backup or replication from happening because other backend sessions are already taken for other purposes by an application, and superuser-only connection slots are not a correct solution to handle that case. This commit makes max_wal_senders independent of max_connections for its handling of PGPROC entries in ProcGlobal, meaning that connection slots for WAL senders are handled using their own free queue, like autovacuum workers and bgworkers. One compatibility issue that this change creates is that a standby now requires to have a value of max_wal_senders at least equal to its primary. So, if a standby created enforces the value of max_wal_senders to be lower than that, then this could break failovers. Normally this should not be an issue though, as any settings of a standby are inherited from its primary as postgresql.conf gets normally copied as part of a base backup, so parameters would be consistent. Author: Alexander Kukushkin Reviewed-by: Kyotaro Horiguchi, Petr Jelínek, Masahiko Sawada, Oleksii Kliukin Discussion: https://postgr.es/m/CAFh8B=nBzHQeYAu0b8fjK-AF1X4+_p6GRtwG+cCgs6Vci2uRuQ@mail.gmail.com
* Remove superfluous tqual.h includes.Andres Freund2019-01-21
| | | | | | | | | | | | Most of these had been obsoleted by 568d4138c / the SnapshotNow removal. This is is preparation for moving most of tqual.[ch] into either snapmgr.h or heapam.h, which in turn is in preparation for pluggable table AMs. Author: Andres Freund Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de
* Replace uses of heap_open et al with the corresponding table_* function.Andres Freund2019-01-21
| | | | | Author: Andres Freund Discussion: https://postgr.es/m/20190111000539.xbv7s6w7ilcvm7dp@alap3.anarazel.de
* Don't include genam.h from execnodes.h and relscan.h anymore.Andres Freund2019-01-14
| | | | | | | | | | | | | | | | | | | This is the genam.h equivalent of 4c850ecec649c (which removed heapam.h from a lot of other headers). There's still a few header includes of genam.h, but not from central headers anymore. As a few headers are not indirectly included anymore, execnodes.h and relscan.h need a few additional includes. Some of the depended on types were replacable by using the underlying structs, but e.g. for Snapshot in execnodes.h that'd have gotten more invasive than reasonable in this commit. Like the aforementioned commit 4c850ecec649c, this requires adding new genam.h includes to a number of backend files, which likely is also required in a few external projects. Author: Andres Freund Discussion: https://postgr.es/m/20190114000701.y4ttcb74jpskkcfb@alap3.anarazel.de
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Remove WITH OIDS support, change oid catalog column visibility.Andres Freund2018-11-20
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously tables declared WITH OIDS, including a significant fraction of the catalog tables, stored the oid column not as a normal column, but as part of the tuple header. This special column was not shown by default, which was somewhat odd, as it's often (consider e.g. pg_class.oid) one of the more important parts of a row. Neither pg_dump nor COPY included the contents of the oid column by default. The fact that the oid column was not an ordinary column necessitated a significant amount of special case code to support oid columns. That already was painful for the existing, but upcoming work aiming to make table storage pluggable, would have required expanding and duplicating that "specialness" significantly. WITH OIDS has been deprecated since 2005 (commit ff02d0a05280e0). Remove it. Removing includes: - CREATE TABLE and ALTER TABLE syntax for declaring the table to be WITH OIDS has been removed (WITH (oids[ = true]) will error out) - pg_dump does not support dumping tables declared WITH OIDS and will issue a warning when dumping one (and ignore the oid column). - restoring an pg_dump archive with pg_restore will warn when restoring a table with oid contents (and ignore the oid column) - COPY will refuse to load binary dump that includes oids. - pg_upgrade will error out when encountering tables declared WITH OIDS, they have to be altered to remove the oid column first. - Functionality to access the oid of the last inserted row (like plpgsql's RESULT_OID, spi's SPI_lastoid, ...) has been removed. The syntax for declaring a table WITHOUT OIDS (or WITH (oids = false) for CREATE TABLE) is still supported. While that requires a bit of support code, it seems unnecessary to break applications / dumps that do not use oids, and are explicit about not using them. The biggest user of WITH OID columns was postgres' catalog. This commit changes all 'magic' oid columns to be columns that are normally declared and stored. To reduce unnecessary query breakage all the newly added columns are still named 'oid', even if a table's column naming scheme would indicate 'reloid' or such. This obviously requires adapting a lot code, mostly replacing oid access via HeapTupleGetOid() with access to the underlying Form_pg_*->oid column. The bootstrap process now assigns oids for all oid columns in genbki.pl that do not have an explicit value (starting at the largest oid previously used), only oids assigned later by oids will be above FirstBootstrapObjectId. As the oid column now is a normal column the special bootstrap syntax for oids has been removed. Oids are not automatically assigned during insertion anymore, all backend code explicitly assigns oids with GetNewOidWithIndex(). For the rare case that insertions into the catalog via SQL are called for the new pg_nextoid() function can be used (which only works on catalog tables). The fact that oid columns on system tables are now normal columns means that they will be included in the set of columns expanded by * (i.e. SELECT * FROM pg_class will now include the table's oid, previously it did not). It'd not technically be hard to hide oid column by default, but that'd mean confusing behavior would either have to be carried forward forever, or it'd cause breakage down the line. While it's not unlikely that further adjustments are needed, the scope/invasiveness of the patch makes it worthwhile to get merge this now. It's painful to maintain externally, too complicated to commit after the code code freeze, and a dependency of a number of other patches. Catversion bump, for obvious reasons. Author: Andres Freund, with contributions by John Naylor Discussion: https://postgr.es/m/20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de
* Refactor pid, random seed and start time initialization.Thomas Munro2018-10-19
| | | | | | | | | | | | | | | | | | | | | | | | Background workers, including parallel workers, were generating the same sequence of numbers in random(). This showed up as DSM handle collisions when Parallel Hash created multiple segments, but any code that calls random() in background workers could be affected if it cares about different backends generating different numbers. Repair by making sure that all new processes initialize the seed at the same time as they set MyProcPid and MyStartTime in a new function InitProcessGlobals(), called by the postmaster, its children and also standalone processes. Also add a new high resolution MyStartTimestamp as a potentially useful by-product, and remove SessionStartTime from struct Port as it is now redundant. No back-patch for now, as the known consequences so far are just a bunch of harmless shm_open(O_EXCL) collisions. Author: Thomas Munro Reviewed-by: Tom Lane Discussion: https://postgr.es/m/CAEepm%3D2eJj_6%3DB%2B2tEpGu2nf1BjthCf9nXXUouYvJJ4C5WSwhg%40mail.gmail.com
* Add application_name to connection authorized msgStephen Frost2018-09-28
| | | | | | | | | | | | | | | | | | | | | The connection authorized message has quite a bit of useful information in it, but didn't include the application_name (when provided), so let's add that as it can be very useful. Note that at the point where we're emitting the connection authorized message, we haven't processed GUCs, so it's not possible to get this by using log_line_prefix (which pulls from the GUC). There's also something to be said for having this included in the connection authorized message and then not needing to repeat it for every line, as having it in log_line_prefix would do. The GUC cleans the application name to pure-ascii, so do that here too, but pull out the logic for cleaning up a string into its own function in common and re-use it from those places, and check_cluster_name which was doing the same thing. Author: Don Seiler <don@seiler.us> Discussion: https://postgr.es/m/CAHJZqBB_Pxv8HRfoh%2BAB4KxSQQuPVvtYCzMg7woNR3r7dfmopw%40mail.gmail.com