aboutsummaryrefslogtreecommitdiff
path: root/src/include/storage/predicate_internals.h
Commit message (Collapse)AuthorAge
* Update copyright for 2024Bruce Momjian2024-01-03
| | | | | | | | Reported-by: Michael Paquier Discussion: https://postgr.es/m/ZZKTDPxBBMt3C0J9@paquier.xyz Backpatch-through: 12
* Add trailing commas to enum definitionsPeter Eisentraut2023-10-26
| | | | | | | | | | | | | | | | | | | | Since C99, there can be a trailing comma after the last value in an enum definition. A lot of new code has been introducing this style on the fly. Some new patches are now taking an inconsistent approach to this. Some add the last comma on the fly if they add a new last value, some are trying to preserve the existing style in each place, some are even dropping the last comma if there was one. We could nudge this all in a consistent direction if we just add the trailing commas everywhere once. I omitted a few places where there was a fixed "last" value that will always stay last. I also skipped the header files of libpq and ecpg, in case people want to use those with older compilers. There were also a small number of cases where the enum type wasn't used anywhere (but the enum values were), which ended up confusing pgindent a bit, so I left those alone. Discussion: https://www.postgresql.org/message-id/flat/386f8c45-c8ac-4681-8add-e3b0852c1620%40eisentraut.org
* Pre-beta mechanical code beautification.Tom Lane2023-05-19
| | | | | | | | | | | | | | | 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/20230428092545.qfb3y5wcu4cm75ur@alvherre.pgsql
* Use dlists instead of SHM_QUEUE for predicate lockingAndres Freund2023-01-19
| | | | | | | | | 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 <thomas.munro@gmail.com> (in an older version) Discussion: https://postgr.es/m/20221120055930.t6kl3tyivzhlrzu2@awork3.anarazel.de Discussion: https://postgr.es/m/20200211042229.msv23badgqljrdg2@alap3.anarazel.de
* Update copyright for 2023Bruce Momjian2023-01-02
| | | | Backpatch-through: 11
* Update copyright for 2022Bruce Momjian2022-01-07
| | | | Backpatch-through: 10
* Change ProcSendSignal() to take pgprocno.Thomas Munro2021-12-16
| | | | | | | | | | | Instead of referring to target backends by pid, use pgprocno. This means that we don't have to scan the ProcArray and we can drop some special case code for dealing with the startup process. Discussion: https://postgr.es/m/CA%2BhUKGLYRyDaneEwz5Uya_OgFLMx5BgJfkQSD%3Dq9HmwsfRRb-w%40mail.gmail.com Reviewed-by: Soumyadeep Chakraborty <soumyadeep2007@gmail.com> Reviewed-by: Ashwin Agrawal <ashwinstar@gmail.com> Reviewed-by: Andres Freund <andres@anarazel.de>
* Update copyright for 2021Bruce Momjian2021-01-02
| | | | Backpatch-through: 9.5
* Rename assorted LWLock tranches.Tom Lane2020-05-15
| | | | | | | | | | | | | | | | Choose names that fit into the conventions for wait event names (particularly, that multi-word names are in the style MultiWordName) and hopefully convey more information to non-hacker users than the previous names did. Also rename SerializablePredicateLockListLock to SerializablePredicateListLock; the old name was long enough to cause table formatting problems, plus the double occurrence of "Lock" seems confusing/error-prone. Also change a couple of particularly opaque LWLock field names. 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
* 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
* Enable parallel query with SERIALIZABLE isolation.Thomas Munro2019-03-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, the SERIALIZABLE isolation level prevented parallel query from being used. Allow the two features to be used together by sharing the leader's SERIALIZABLEXACT with parallel workers. An extra per-SERIALIZABLEXACT LWLock is introduced to make it safe to share, and new logic is introduced to coordinate the early release of the SERIALIZABLEXACT required for the SXACT_FLAG_RO_SAFE optimization, as follows: The first backend to observe the SXACT_FLAG_RO_SAFE flag (set by some other transaction) will 'partially release' the SERIALIZABLEXACT, meaning that the conflicts and locks it holds are released, but the SERIALIZABLEXACT itself will remain active because other backends might still have a pointer to it. Whenever any backend notices the SXACT_FLAG_RO_SAFE flag, it clears its own MySerializableXact variable and frees local resources so that it can skip SSI checks for the rest of the transaction. In the special case of the leader process, it transfers the SERIALIZABLEXACT to a new variable SavedSerializableXact, so that it can be completely released at the end of the transaction after all workers have exited. Remove the serializable_okay flag added to CreateParallelContext() by commit 9da0cc35, because it's now redundant. Author: Thomas Munro Reviewed-by: Haribabu Kommi, Robert Haas, Masahiko Sawada, Kevin Grittner Discussion: https://postgr.es/m/CAEepm=0gXGYhtrVDWOTHS8SQQy_=S9xo+8oCxGLWZAOoeJ=yzQ@mail.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
* 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
* Initial pgindent run with pg_bsd_indent version 2.0.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The new indent version includes numerous fixes thanks to Piotr Stefaniak. The main changes visible in this commit are: * Nicer formatting of function-pointer declarations. * No longer unexpectedly removes spaces in expressions using casts, sizeof, or offsetof. * No longer wants to add a space in "struct structname *varname", as well as some similar cases for const- or volatile-qualified pointers. * Declarations using PG_USED_FOR_ASSERTS_ONLY are formatted more nicely. * Fixes bug where comments following declarations were sometimes placed with no space separating them from the code. * Fixes some odd decisions for comments following case labels. * Fixes some cases where comments following code were indented to less than the expected column 33. On the less good side, it now tends to put more whitespace around typedef names that are not listed in typedefs.list. This might encourage us to put more effort into typedef name collection; it's not really a bug in indent itself. There are more changes coming after this round, having to do with comment indentation and alignment of lines appearing within parentheses. I wanted to limit the size of the diffs to something that could be reviewed without one's eyes completely glazing over, so it seemed better to split up the changes as much as practical. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Move isolationtester's is-blocked query into C code for speed.Tom Lane2017-04-10
| | | | | | | | | | | | | | | | | | | Commit 4deb41381 modified isolationtester's query to see whether a session is blocked to also check for waits occurring in GetSafeSnapshot. However, it did that in a way that enormously increased the query's runtime under CLOBBER_CACHE_ALWAYS, causing the buildfarm members that use that to run about four times slower than before, and in some cases fail entirely. To fix, push the entire logic into a dedicated backend function. This should actually reduce the CLOBBER_CACHE_ALWAYS runtime from what it was previously, though I've not checked that. In passing, expose a SQL function to check for safe-snapshot blockage, comparable to pg_blocking_pids. This is more or less free given the infrastructure built to solve the other problem, so we might as well. Thomas Munro Discussion: https://postgr.es/m/20170407165749.pstcakbc637opkax@alap3.anarazel.de
* Update copyright via script for 2017Bruce Momjian2017-01-03
|
* Update copyright for 2016Bruce Momjian2016-01-02
| | | | Backpatch certain files through 9.1
* Define integer limits independently from the system definitions.Andres Freund2015-04-02
| | | | | | | | | | | | | | | | | | | | | In 83ff1618 we defined integer limits iff they're not provided by the system. That turns out not to be the greatest idea because there's different ways some datatypes can be represented. E.g. on OSX PG's 64bit datatype will be a 'long int', but OSX unconditionally uses 'long long'. That disparity then can lead to warnings, e.g. around printf formats. One way to fix that would be to back int64 using stdint.h's int64_t. While a good idea it's not that easy to implement. We would e.g. need to include stdint.h in our external headers, which we don't today. Also computing the correct int64 printf formats in that case is nontrivial. Instead simply prefix the integer limits with PG_ and define them unconditionally. I've adjusted all the references to them in code, but not the ones in comments; the latter seems unnecessary to me. Discussion: 20150331141423.GK4878@alap3.anarazel.de
* Centralize definition of integer limits.Andres Freund2015-03-25
| | | | | | | | | | | | | | | | | Several submitted and even committed patches have run into the problem that C89, our baseline, does not provide minimum/maximum values for various integer datatypes. C99's stdint.h does, but we can't rely on it. Several parts of the code defined limits locally, so instead centralize the definitions to c.h. This patch also changes the more obvious usages of literal limit values; there's more places that could be changed, but it's less clear whether it's beneficial to change those. Author: Andrew Gierth Discussion: 87619tc5wc.fsf@news-spur.riddles.org.uk
* Update copyright for 2015Bruce Momjian2015-01-06
| | | | Backpatch certain files through 9.0
* pgindent run for 9.4Bruce Momjian2014-05-06
| | | | | This includes removing tabs after periods in C comments, which was applied to back branches, so this change should not effect backpatching.
* Update copyright for 2014Bruce Momjian2014-01-07
| | | | | Update all files in head, and files COPYRIGHT and legal.sgml in all back branches.
* Eliminate xmin from hash tag for predicate locks on heap tuples.Kevin Grittner2013-10-07
| | | | | | | | | | | | | | | | If a tuple was frozen while its predicate locks mattered, read-write dependencies could be missed, resulting in failure to detect conflicts which could lead to anomalies in committed serializable transactions. This field was added to the tag when we still thought that it was necessary to carry locks forward to a new version of an updated row. That was later proven to be unnecessary, which allowed simplification of the code, but elimination of xmin from the tag was missed at the time. Per report and analysis by Heikki Linnakangas. Backpatch to 9.1.
* pgindent run for release 9.3Bruce Momjian2013-05-29
| | | | | This is the first run of the Perl-based pgindent script. Also update pgindent instructions.
* Update copyrights for 2013Bruce Momjian2013-01-01
| | | | | Fully update git head, and update back branches in ./COPYRIGHT and legal.sgml files.
* Update copyright notices for year 2012.Bruce Momjian2012-01-01
|
* SSI has a race condition, where the order of commit sequence numbers ofHeikki Linnakangas2011-07-07
| | | | | | | | | | | | | | | transactions might not match the order the work done in those transactions become visible to others. The logic in SSI, however, assumed that it does. Fix that by having two sequence numbers for each serializable transaction, one taken before a transaction becomes visible to others, and one after it. This is easier than trying to make the the transition totally atomic, which would require holding ProcArrayLock and SerializableXactHashLock at the same time. By using prepareSeqNo instead of commitSeqNo in a few places where commit sequence numbers are compared, we can make those comparisons err on the safe side when we don't know for sure which committed first. Per analysis by Kevin Grittner and Dan Ports, but this approach to fix it is different from the original patch.
* Fix bug introduced by recent SSI patch to merge ROLLED_BACK andHeikki Linnakangas2011-06-21
| | | | | | | | | | MARKED_FOR_DEATH flags into one. We still need the ROLLED_BACK flag to mark transactions that are in the process of being rolled back. To be precise, ROLLED_BACK now means that a transaction has already been discounted from the count of transactions with the oldest xmin, but not yet removed from the list of active transactions. Dan Ports
* pgindent run of recent SSI changes. Also, remove an unnecessary #include.Heikki Linnakangas2011-06-16
| | | | Kevin Grittner
* The rolled-back flag on serializable xacts was pointless and redundant withHeikki Linnakangas2011-06-15
| | | | | | | | the marked-for-death flag. It was only set for a fleeting moment while a transaction was being cleaned up at rollback. All the places that checked for the rolled-back flag should also check the marked-for-death flag, as both flags mean that the transaction will roll back. I also renamed the marked-for-death into "doomed", which is a lot shorter name.
* Fix locking while setting flags in MySerializableXact.Heikki Linnakangas2011-06-10
| | | | | | | | | | | | | | | | | Even if a flag is modified only by the backend owning the transaction, it's not safe to modify it without a lock. Another backend might be setting or clearing a different flag in the flags field concurrently, and that operation might be lost because setting or clearing a bit in a word is not atomic. Make did-write flag a simple backend-private boolean variable, because it was only set or tested in the owning backend (except when committing a prepared transaction, but it's not worthwhile to optimize for the case of a read-only prepared transaction). This also eliminates the need to add locking where that flag is set. Also, set the did-write flag when doing DDL operations like DROP TABLE or TRUNCATE -- that was missed earlier.
* Small comment fixes and enhancements.Heikki Linnakangas2011-06-10
|
* Make DDL operations play nicely with Serializable Snapshot Isolation.Heikki Linnakangas2011-06-08
| | | | | | | | | | | | | | Truncating or dropping a table is treated like deletion of all tuples, and check for conflicts accordingly. If a table is clustered or rewritten by ALTER TABLE, all predicate locks on the heap are promoted to relation-level locks, because the tuple or page ids of any existing tuples will change and won't be valid after rewriting the table. Arguably ALTER TABLE should be treated like a mass-UPDATE of every row, but if you e.g change the datatype of a column, you could also argue that it's just a change to the physical layout, not a logical change. Reindexing promotes all locks on the index to relation-level lock on the heap. Kevin Grittner, with a lot of cosmetic changes by me.
* SSI comment fixes and enhancements. Notably, document that the conflict-outHeikki Linnakangas2011-06-03
| | | | | | | flag actually means that the transaction has a conflict out to a transaction that committed before the flagged transaction. Kevin Grittner
* pgindent run before PG 9.1 beta 1.Bruce Momjian2011-04-10
|
* Fix bugs in Serializable Snapshot Isolation.Heikki Linnakangas2011-03-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | Change the way UPDATEs are handled. Instead of maintaining a chain of tuple-level locks in shared memory, copy any existing locks on the old tuple to the new tuple at UPDATE. Any existing page-level lock needs to be duplicated too, as a lock on the new tuple. That was neglected previously. Store xmin on tuple-level predicate locks, to distinguish a lock on an old already-recycled tuple from a new tuple at the same physical location. Failure to distinguish them caused loops in the tuple-lock chains, as reported by YAMAMOTO Takashi. Although we don't use the chain representation of UPDATEs anymore, it seems like a good idea to store the xmin to avoid some false positives if no other reason. CheckSingleTargetForConflictsIn now correctly handles the case where a lock that's being held is not reflected in the local lock table. That happens if another backend acquires a lock on our behalf due to an UPDATE or a page split. PredicateLockPageCombine now retains locks for the page that is being removed, rather than removing them. This prevents a potentially dangerous false-positive inconsistency where the local lock table believes that a lock is held, but it is actually not. Dan Ports and Kevin Grittner
* UINT64_MAX isn't defined on MSVC.Heikki Linnakangas2011-02-08
|
* Implement genuine serializable isolation level.Heikki Linnakangas2011-02-08
Until now, our Serializable mode has in fact been what's called Snapshot Isolation, which allows some anomalies that could not occur in any serialized ordering of the transactions. This patch fixes that using a method called Serializable Snapshot Isolation, based on research papers by Michael J. Cahill (see README-SSI for full references). In Serializable Snapshot Isolation, transactions run like they do in Snapshot Isolation, but a predicate lock manager observes the reads and writes performed and aborts transactions if it detects that an anomaly might occur. This method produces some false positives, ie. it sometimes aborts transactions even though there is no anomaly. To track reads we implement predicate locking, see storage/lmgr/predicate.c. Whenever a tuple is read, a predicate lock is acquired on the tuple. Shared memory is finite, so when a transaction takes many tuple-level locks on a page, the locks are promoted to a single page-level lock, and further to a single relation level lock if necessary. To lock key values with no matching tuple, a sequential scan always takes a relation-level lock, and an index scan acquires a page-level lock that covers the search key, whether or not there are any matching keys at the moment. A predicate lock doesn't conflict with any regular locks or with another predicate locks in the normal sense. They're only used by the predicate lock manager to detect the danger of anomalies. Only serializable transactions participate in predicate locking, so there should be no extra overhead for for other transactions. Predicate locks can't be released at commit, but must be remembered until all the transactions that overlapped with it have completed. That means that we need to remember an unbounded amount of predicate locks, so we apply a lossy but conservative method of tracking locks for committed transactions. If we run short of shared memory, we overflow to a new "pg_serial" SLRU pool. We don't currently allow Serializable transactions in Hot Standby mode. That would be hard, because even read-only transactions can cause anomalies that wouldn't otherwise occur. Serializable isolation mode now means the new fully serializable level. Repeatable Read gives you the old Snapshot Isolation level that we have always had. Kevin Grittner and Dan Ports, reviewed by Jeff Davis, Heikki Linnakangas and Anssi Kääriäinen