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2019-04-09Define WIN32_STACK_RLIMIT throughout win32 and cygwin builds.Noah Misch
The MSVC build system already did this, and commit 617dc6d299c957e2784320382b3277ede01d9c63 used it in a second file. Back-patch to 9.4, like that commit. Discussion: https://postgr.es/m/CAA8=A7_1SWc3+3Z=-utQrQFOtrj_DeohRVt7diA2tZozxsyUOQ@mail.gmail.com
2019-01-25Allow UNLISTEN in hot-standby mode.Tom Lane
Since LISTEN is (still) disallowed, UNLISTEN must be a no-op in a hot-standby session, and so there's no harm in allowing it. This change allows client code to not worry about whether it's connected to a primary or standby server when performing session-state-reset type activities. (Note that DISCARD ALL, which includes UNLISTEN, was already allowed, making it inconsistent to reject UNLISTEN.) Per discussion, back-patch to all supported versions. Shay Rojansky, reviewed by Mi Tar Discussion: https://postgr.es/m/CADT4RqCf2gA_TJtPAjnGzkC3ZiexfBZiLmA-mV66e4UyuVv8bA@mail.gmail.com
2018-10-19Server-side fix for delayed NOTIFY and SIGTERM processing.Tom Lane
Commit 4f85fde8e introduced some code that was meant to ensure that we'd process cancel, die, sinval catchup, and notify interrupts while waiting for client input. But there was a flaw: it supposed that the process latch would be set upon arrival at secure_read() if any such interrupt was pending. In reality, we might well have cleared the process latch at some earlier point while those flags remained set -- particularly notifyInterruptPending, which can't be handled as long as we're within a transaction. To fix the NOTIFY case, also attempt to process signals (except ProcDiePending) before trying to read. Also, if we see that ProcDiePending is set before we read, forcibly set the process latch to ensure that we will handle that signal promptly if no data is available. I also made it set the process latch on the way out, in case there is similar logic elsewhere. (It remains true that we won't service ProcDiePending here unless we need to wait for input.) The code for handling ProcDiePending during a write needs those changes, too. Also be a little more careful about when to reset whereToSendOutput, and improve related comments. Back-patch to 9.5 where this code was added. I'm not entirely convinced that older branches don't have similar issues, but the complaint at hand is just about the >= 9.5 code. Jeff Janes and Tom Lane Discussion: https://postgr.es/m/CAOYf6ec-TmRYjKBXLLaGaB-jrd=mjG1Hzn1a1wufUAR39PQYhw@mail.gmail.com
2018-10-15Check for stack overrun in standard_ProcessUtility().Tom Lane
ProcessUtility can recurse, and indeed can be driven to infinite recursion, so it ought to have a check_stack_depth() call. This covers the reported bug (portal trying to execute itself) and a bunch of other cases that could perhaps arise somewhere. Per bug #15428 from Malthe Borch. Back-patch to all supported branches. Discussion: https://postgr.es/m/15428-b3c2915ec470b033@postgresql.org
2018-08-08Don't run atexit callbacks in quickdie signal handlers.Heikki Linnakangas
exit() is not async-signal safe. Even if the libc implementation is, 3rd party libraries might have installed unsafe atexit() callbacks. After receiving SIGQUIT, we really just want to exit as quickly as possible, so we don't really want to run the atexit() callbacks anyway. The original report by Jimmy Yih was a self-deadlock in startup_die(). However, this patch doesn't address that scenario; the signal handling while waiting for the startup packet is more complicated. But at least this alleviates similar problems in the SIGQUIT handlers, like that reported by Asim R P later in the same thread. Backpatch to 9.3 (all supported versions). Discussion: https://www.postgresql.org/message-id/CAOMx_OAuRUHiAuCg2YgicZLzPVv5d9_H4KrL_OFsFP%3DVPekigA%40mail.gmail.com
2017-06-05Unify SIGHUP handling between normal and walsender backends.Andres Freund
Because walsender and normal backends share the same main loop it's problematic to have two different flag variables, set in signal handlers, indicating a pending configuration reload. Only certain walsender commands reach code paths checking for the variable (START_[LOGICAL_]REPLICATION, CREATE_REPLICATION_SLOT ... LOGICAL, notably not base backups). This is a bug present since the introduction of walsender, but has gotten worse in releases since then which allow walsender to do more. A later patch, not slated for v10, will similarly unify SIGHUP handling in other types of processes as well. Author: Petr Jelinek, Andres Freund Reviewed-By: Michael Paquier Discussion: https://postgr.es/m/20170423235941.qosiuoyqprq4nu7v@alap3.anarazel.de Backpatch: 9.2-, bug is present since 9.0
2017-04-06Remove dead code and fix comments in fast-path function handling.Heikki Linnakangas
HandleFunctionRequest() is no longer responsible for reading the protocol message from the client, since commit 2b3a8b20c2. Fix the outdated comments. HandleFunctionRequest() now always returns 0, because the code that used to return EOF was moved in 2b3a8b20c2. Therefore, the caller no longer needs to check the return value. Reported by Andres Freund. Backpatch to all supported versions, even though this doesn't have any user-visible effect, to make backporting future patches in this area easier. Discussion: https://www.postgresql.org/message-id/20170405010525.rt5azbya5fkbhvrx@alap3.anarazel.de
2017-01-26Add castNode(type, ptr) for safe casting between NodeTag based types.Andres Freund
The new function allows to cast from one NodeTag based type to another, while asserting that the conversion is valid. This replaces the common pattern of doing a cast and a Assert(IsA(ptr, type)) close-by. As this seems likely to be used pervasively, we decided to backpatch this change the addition of this macro. Otherwise backpatched fixes are more likely not to work on back-branches. On branches before 9.6, where we do not yet rely on inline functions being available, the type assertion is only performed if PG_USE_INLINE support is detected. The cast obviously is performed regardless. For the benefit of verifying the macro compiles in the back-branches, this commit contains a single use of the new macro. On master, a somewhat larger conversion will be committed separately. Author: Peter Eisentraut and Andres Freund Reviewed-By: Tom Lane Discussion: https://postgr.es/m/c5d387d9-3440-f5e0-f9d4-71d53b9fbe52@2ndquadrant.com Backpatch: 9.2-
2016-12-22Use TSConfigRelationId in AlterTSConfiguration()Stephen Frost
When we are altering a text search configuration, we are getting the tuple from pg_ts_config and using its OID, so use TSConfigRelationId when invoking any post-alter hooks and setting the object address. Further, in the functions called from AlterTSConfiguration(), we're saving information about the command via EventTriggerCollectAlterTSConfig(), so we should be setting commandCollected to true. Also add a regression test to test_ddl_deparse for ALTER TEXT SEARCH CONFIGURATION. Author: Artur Zakirov, a few additional comments by me Discussion: https://www.postgresql.org/message-id/57a71eba-f2c7-e7fd-6fc0-2126ec0b39bd%40postgrespro.ru Back-patch the fix for the InvokeObjectPostAlterHook() call to 9.3 where it was introduced, and the fix for the ObjectAddressSet() call and setting commandCollected to true to 9.5 where those changes to ProcessUtilitySlow() were introduced.
2016-11-15Account for catalog snapshot in PGXACT->xmin updates.Tom Lane
The CatalogSnapshot was not plugged into SnapshotResetXmin()'s accounting for whether MyPgXact->xmin could be cleared or advanced. In normal transactions this was masked by the fact that the transaction snapshot would be older, but during backend startup and certain utility commands it was possible to re-use the CatalogSnapshot after MyPgXact->xmin had been cleared, meaning that recently-deleted rows could be pruned even though this snapshot could still see them, causing unexpected catalog lookup failures. This effect appears to be the explanation for a recent failure on buildfarm member piculet. To fix, add the CatalogSnapshot to the RegisteredSnapshots heap whenever it is valid. In the previous logic, it was possible for the CatalogSnapshot to remain valid across waits for client input, but with this change that would mean it delays advance of global xmin in cases where it did not before. To avoid possibly causing new table-bloat problems with clients that sit idle for long intervals, add code to invalidate the CatalogSnapshot before waiting for client input. (When the backend is busy, it's unlikely that the CatalogSnapshot would be the oldest snap for very long, so we don't worry about forcing early invalidation of it otherwise.) In passing, remove the CatalogSnapshotStale flag in favor of using "CatalogSnapshot != NULL" to represent validity, as we do for the other special snapshots in snapmgr.c. And improve some obsolete comments. No regression test because I don't know a deterministic way to cause this failure. But the stress test shown in the original discussion provokes "cache lookup failed for relation 1255" within a few dozen seconds for me. Back-patch to 9.4 where MVCC catalog scans were introduced. (Note: it's quite easy to produce similar failures with the same test case in branches before 9.4. But MVCC catalog scans were supposed to fix that.) Discussion: <16447.1478818294@sss.pgh.pa.us>
2016-05-27Be more predictable about reporting "lock timeout" vs "statement timeout".Tom Lane
If both timeout indicators are set when we arrive at ProcessInterrupts, we've historically just reported "lock timeout". However, some buildfarm members have been observed to fail isolationtester's timeouts test by reporting "lock timeout" when the statement timeout was expected to fire first. The cause seems to be that the process is allowed to sleep longer than expected (probably due to heavy machine load) so that the lock timeout happens before we reach the point of reporting the error, and then this arbitrary tiebreak rule does the wrong thing. We can improve matters by comparing the scheduled timeout times to decide which error to report. I had originally proposed greatly reducing the 1-second window between the two timeouts in the test cases. On reflection that is a bad idea, at least for the case where the lock timeout is expected to fire first, because that would assume that it takes negligible time to get from statement start to the beginning of the lock wait. Thus, this patch doesn't completely remove the risk of test failures on slow machines. Empirically, however, the case this handles is the one we are seeing in the buildfarm. The explanation may be that the other case requires the scheduler to take the CPU away from a busy process, whereas the case fixed here only requires the scheduler to not give the CPU back right away to a process that has been woken from a multi-second sleep (and, perhaps, has been swapped out meanwhile). Back-patch to 9.3 where the isolationtester timeouts test was added. Discussion: <8693.1464314819@sss.pgh.pa.us>
2015-10-28Message style improvementsPeter Eisentraut
Message style, plurals, quoting, spelling, consistency with similar messages
2015-10-02Add recursion depth protections to regular expression matching.Tom Lane
Some of the functions in regex compilation and execution recurse, and therefore could in principle be driven to stack overflow. The Tcl crew has seen this happen in practice in duptraverse(), though their fix was to put in a hard-wired limit on the number of recursive levels, which is not too appetizing --- fortunately, we have enough infrastructure to check the actually available stack. Greg Stark has also seen it in other places while fuzz testing on a machine with limited stack space. Let's put guards in to prevent crashes in all these places. Since the regex code would leak memory if we simply threw elog(ERROR), we have to introduce an API that checks for stack depth without throwing such an error. Fortunately that's not difficult.
2015-09-04Fix subtransaction cleanup after an outer-subtransaction portal fails.Tom Lane
Formerly, we treated only portals created in the current subtransaction as having failed during subtransaction abort. However, if the error occurred while running a portal created in an outer subtransaction (ie, a cursor declared before the last savepoint), that has to be considered broken too. To allow reliable detection of which ones those are, add a bookkeeping field to struct Portal that tracks the innermost subtransaction in which each portal has actually been executed. (Without this, we'd end up failing portals containing functions that had called the subtransaction, thereby breaking plpgsql exception blocks completely.) In addition, when we fail an outer-subtransaction Portal, transfer its resources into the subtransaction's resource owner, so that they're released early in cleanup of the subxact. This fixes a problem reported by Jim Nasby in which a function executed in an outer-subtransaction cursor could cause an Assert failure or crash by referencing a relation created within the inner subtransaction. The proximate cause of the Assert failure is that AtEOSubXact_RelationCache assumed it could blow away a relcache entry without first checking that the entry had zero refcount. That was a bad idea on its own terms, so add such a check there, and to the similar coding in AtEOXact_RelationCache. This provides an independent safety measure in case there are still ways to provoke the situation despite the Portal-level changes. This has been broken since subtransactions were invented, so back-patch to all supported branches. Tom Lane and Michael Paquier
2015-06-26Fix DDL command collection for TRANSFORMAlvaro Herrera
Commit b488c580ae, which added the DDL command collection feature, neglected to update the code that commit cac76582053e had previously added two weeks earlier for the TRANSFORM feature. Reported by Michael Paquier.
2015-05-23pgindent run for 9.5Bruce Momjian
2015-05-23Remove the new UPSERT command tag and use INSERT instead.Andres Freund
Previously, INSERT with ON CONFLICT DO UPDATE specified used a new command tag -- UPSERT. It was introduced out of concern that INSERT as a command tag would be a misrepresentation for ON CONFLICT DO UPDATE, as some affected rows may actually have been updated. Alvaro Herrera noticed that the implementation of that new command tag was incomplete; in subsequent discussion we concluded that having it doesn't provide benefits that are in line with the compatibility breaks it requires. Catversion bump due to the removal of PlannedStmt->isUpsert. Author: Peter Geoghegan Discussion: 20150520215816.GI5885@postgresql.org
2015-05-15Support VERBOSE option in REINDEX command.Fujii Masao
When this option is specified, a progress report is printed as each index is reindexed. Per discussion, we agreed on the following syntax for the extensibility of the options. REINDEX (flexible options) { INDEX | ... } name Sawada Masahiko. Reviewed by Robert Haas, Fabrízio Mello, Alvaro Herrera, Kyotaro Horiguchi, Jim Nasby and me. Discussion: CAD21AoA0pK3YcOZAFzMae+2fcc3oGp5zoRggDyMNg5zoaWDhdQ@mail.gmail.com
2015-05-11Allow on-the-fly capture of DDL event detailsAlvaro Herrera
This feature lets user code inspect and take action on DDL events. Whenever a ddl_command_end event trigger is installed, DDL actions executed are saved to a list which can be inspected during execution of a function attached to ddl_command_end. The set-returning function pg_event_trigger_ddl_commands can be used to list actions so captured; it returns data about the type of command executed, as well as the affected object. This is sufficient for many uses of this feature. For the cases where it is not, we also provide a "command" column of a new pseudo-type pg_ddl_command, which is a pointer to a C structure that can be accessed by C code. The struct contains all the info necessary to completely inspect and even reconstruct the executed command. There is no actual deparse code here; that's expected to come later. What we have is enough infrastructure that the deparsing can be done in an external extension. The intention is that we will add some deparsing code in a later release, as an in-core extension. A new test module is included. It's probably insufficient as is, but it should be sufficient as a starting point for a more complete and future-proof approach. Authors: Álvaro Herrera, with some help from Andres Freund, Ian Barwick, Abhijit Menon-Sen. Reviews by Andres Freund, Robert Haas, Amit Kapila, Michael Paquier, Craig Ringer, David Steele. Additional input from Chris Browne, Dimitri Fontaine, Stephen Frost, Petr Jelínek, Tom Lane, Jim Nasby, Steven Singer, Pavel Stěhule. Based on original work by Dimitri Fontaine, though I didn't use his code. Discussion: https://www.postgresql.org/message-id/m2txrsdzxa.fsf@2ndQuadrant.fr https://www.postgresql.org/message-id/20131108153322.GU5809@eldon.alvh.no-ip.org https://www.postgresql.org/message-id/20150215044814.GL3391@alvh.no-ip.org
2015-05-08Add support for INSERT ... ON CONFLICT DO NOTHING/UPDATE.Andres Freund
The newly added ON CONFLICT clause allows to specify an alternative to raising a unique or exclusion constraint violation error when inserting. ON CONFLICT refers to constraints that can either be specified using a inference clause (by specifying the columns of a unique constraint) or by naming a unique or exclusion constraint. DO NOTHING avoids the constraint violation, without touching the pre-existing row. DO UPDATE SET ... [WHERE ...] updates the pre-existing tuple, and has access to both the tuple proposed for insertion and the existing tuple; the optional WHERE clause can be used to prevent an update from being executed. The UPDATE SET and WHERE clauses have access to the tuple proposed for insertion using the "magic" EXCLUDED alias, and to the pre-existing tuple using the table name or its alias. This feature is often referred to as upsert. This is implemented using a new infrastructure called "speculative insertion". It is an optimistic variant of regular insertion that first does a pre-check for existing tuples and then attempts an insert. If a violating tuple was inserted concurrently, the speculatively inserted tuple is deleted and a new attempt is made. If the pre-check finds a matching tuple the alternative DO NOTHING or DO UPDATE action is taken. If the insertion succeeds without detecting a conflict, the tuple is deemed inserted. To handle the possible ambiguity between the excluded alias and a table named excluded, and for convenience with long relation names, INSERT INTO now can alias its target table. Bumps catversion as stored rules change. Author: Peter Geoghegan, with significant contributions from Heikki Linnakangas and Andres Freund. Testing infrastructure by Jeff Janes. Reviewed-By: Heikki Linnakangas, Andres Freund, Robert Haas, Simon Riggs, Dean Rasheed, Stephen Frost and many others.
2015-04-30Create an infrastructure for parallel computation in PostgreSQL.Robert Haas
This does four basic things. First, it provides convenience routines to coordinate the startup and shutdown of parallel workers. Second, it synchronizes various pieces of state (e.g. GUCs, combo CID mappings, transaction snapshot) from the parallel group leader to the worker processes. Third, it prohibits various operations that would result in unsafe changes to that state while parallelism is active. Finally, it propagates events that would result in an ErrorResponse, NoticeResponse, or NotifyResponse message being sent to the client from the parallel workers back to the master, from which they can then be sent on to the client. Robert Haas, Amit Kapila, Noah Misch, Rushabh Lathia, Jeevan Chalke. Suggestions and review from Andres Freund, Heikki Linnakangas, Noah Misch, Simon Riggs, Euler Taveira, and Jim Nasby.
2015-04-26Add transforms featurePeter Eisentraut
This provides a mechanism for specifying conversions between SQL data types and procedural languages. As examples, there are transforms for hstore and ltree for PL/Perl and PL/Python. reviews by Pavel Stěhule and Andres Freund
2015-03-25Add OID output argument to DefineTSConfigurationAlvaro Herrera
... which is set to the OID of a copied text search config, whenever the COPY clause is used. This is in the spirit of commit a2e35b53c39.
2015-03-18Rationalize vacuuming options and parametersAlvaro Herrera
We were involving the parser too much in setting up initial vacuuming parameters. This patch moves that responsibility elsewhere to simplify code, and also to make future additions easier. To do this, create a new struct VacuumParams which is filled just prior to vacuum execution, instead of at parse time; for user-invoked vacuuming this is set up in a new function ExecVacuum, while autovacuum sets it up by itself. While at it, add a new member VACOPT_SKIPTOAST to enum VacuumOption, only set by autovacuum, which is used to disable vacuuming of the toast table instead of the old do_toast parameter; this relieves the argument list of vacuum() and some callees a bit. This partially makes up for having added more arguments in an effort to avoid having autovacuum from constructing a VacuumStmt parse node. Author: Michael Paquier. Some tweaks by Álvaro Reviewed by: Robert Haas, Stephen Frost, Álvaro Herrera
2015-03-15Improve representation of PlanRowMark.Tom Lane
This patch fixes two inadequacies of the PlanRowMark representation. First, that the original LockingClauseStrength isn't stored (and cannot be inferred for foreign tables, which always get ROW_MARK_COPY). Since some PlanRowMarks are created out of whole cloth and don't actually have an ancestral RowMarkClause, this requires adding a dummy LCS_NONE value to enum LockingClauseStrength, which is fairly annoying but the alternatives seem worse. This fix allows getting rid of the use of get_parse_rowmark() in FDWs (as per the discussion around commits 462bd95705a0c23b and 8ec8760fc87ecde0), and it simplifies some things elsewhere. Second, that the representation assumed that all child tables in an inheritance hierarchy would use the same RowMarkType. That's true today but will soon not be true. We add an "allMarkTypes" field that identifies the union of mark types used in all a parent table's children, and use that where appropriate (currently, only in preprocess_targetlist()). In passing fix a couple of minor infelicities left over from the SKIP LOCKED patch, notably that _outPlanRowMark still thought waitPolicy is a bool. Catversion bump is required because the numeric values of enum LockingClauseStrength can appear in on-disk rules. Extracted from a much larger patch to support foreign table inheritance; it seemed worth breaking this out, since it's a separable concern. Shigeru Hanada and Etsuro Fujita, somewhat modified by me
2015-03-08Code cleanup for REINDEX DATABASE/SCHEMA/SYSTEM.Tom Lane
Fix some minor infelicities. Some of these things were introduced in commit fe263d115a7dd16095b8b8f1e943aff2bb4574d2, and some are older.
2015-03-08Fix erroneous error message for REINDEX SYSTEM.Tom Lane
Missed case in commit fe263d115a7dd16095b8b8f1e943aff2bb4574d2. Sawada Masahiko
2015-03-03Change many routines to return ObjectAddress rather than OIDAlvaro Herrera
The changed routines are mostly those that can be directly called by ProcessUtilitySlow; the intention is to make the affected object information more precise, in support for future event trigger changes. Originally it was envisioned that the OID of the affected object would be enough, and in most cases that is correct, but upon actually implementing the event trigger changes it turned out that ObjectAddress is more widely useful. Additionally, some command execution routines grew an output argument that's an object address which provides further info about the executed command. To wit: * for ALTER DOMAIN / ADD CONSTRAINT, it corresponds to the address of the new constraint * for ALTER OBJECT / SET SCHEMA, it corresponds to the address of the schema that originally contained the object. * for ALTER EXTENSION {ADD, DROP} OBJECT, it corresponds to the address of the object added to or dropped from the extension. There's no user-visible change in this commit, and no functional change either. Discussion: 20150218213255.GC6717@tamriel.snowman.net Reviewed-By: Stephen Frost, Andres Freund
2015-02-23Fix stupid merge errors in previous commitAlvaro Herrera
Brown paper bag installed permanently.
2015-02-23Support more commands in event triggersAlvaro Herrera
COMMENT, SECURITY LABEL, and GRANT/REVOKE now also fire ddl_command_start and ddl_command_end event triggers, when they operate on database-local objects. Reviewed-By: Michael Paquier, Andres Freund, Stephen Frost
2015-02-20Use FLEXIBLE_ARRAY_MEMBER in a bunch more places.Tom Lane
Replace some bogus "x[1]" declarations with "x[FLEXIBLE_ARRAY_MEMBER]". Aside from being more self-documenting, this should help prevent bogus warnings from static code analyzers and perhaps compiler misoptimizations. This patch is just a down payment on eliminating the whole problem, but it gets rid of a lot of easy-to-fix cases. Note that the main problem with doing this is that one must no longer rely on computing sizeof(the containing struct), since the result would be compiler-dependent. Instead use offsetof(struct, lastfield). Autoconf also warns against spelling that offsetof(struct, lastfield[0]). Michael Paquier, review and additional fixes by me.
2015-02-03Remove ill-conceived Assertion in ProcessClientWriteInterrupt().Andres Freund
It's perfectly fine to have blocked interrupts when ProcessClientWriteInterrupt() is called. In fact it's commonly the case when emitting error reports. And we deal with that correctly. Even if that'd not be the case, it'd be a bad location for such a assertion. Because ProcessClientWriteInterrupt() is only called when the socket is blocked it's hard to hit. Per Heikki and buildfarm animals nightjar and dunlin.
2015-02-03Remove remnants of ImmediateInterruptOK handling.Andres Freund
Now that nothing sets ImmediateInterruptOK to true anymore, we can remove all the supporting code. Reviewed-By: Heikki Linnakangas
2015-02-03Don't allow immediate interrupts during authentication anymore.Andres Freund
We used to handle authentication_timeout by setting ImmediateInterruptOK to true during large parts of the authentication phase of a new connection. While that happens to work acceptably in practice, it's not particularly nice and has ugly corner cases. Previous commits converted the FE/BE communication to use latches and implemented support for interrupt handling during both send/recv. Building on top of that work we can get rid of ImmediateInterruptOK during authentication, by immediately treating timeouts during authentication as a reason to die. As die interrupts are handled immediately during client communication that provides a sensibly quick reaction time to authentication timeout. Additionally add a few CHECK_FOR_INTERRUPTS() to some more complex authentication methods. More could be added, but this already should provides a reasonable coverage. While it this overall increases the maximum time till a timeout is reacted to, it greatly reduces complexity and increases reliability. That seems like a overall win. If the increase proves to be noticeable we can deal with those cases by moving to nonblocking network code and add interrupt checking there. Reviewed-By: Heikki Linnakangas
2015-02-03Process 'die' interrupts while reading/writing from the client socket.Andres Freund
Up to now it was impossible to terminate a backend that was trying to send/recv data to/from the client when the socket's buffer was already full/empty. While the send/recv calls itself might have gotten interrupted by signals on some platforms, we just immediately retried. That could lead to situations where a backend couldn't be terminated , after a client died without the connection being closed, because it was blocked in send/recv. The problem was far more likely to be hit when sending data than when reading. That's because while reading a command from the client, and during authentication, we processed interrupts immediately . That primarily left COPY FROM STDIN as being problematic for recv. Change things so that that we process 'die' events immediately when the appropriate signal arrives. We can't sensibly react to query cancels at that point, because we might loose sync with the client as we could be in the middle of writing a message. We don't interrupt writes if the write buffer isn't full, as indicated by write() returning EWOULDBLOCK, as that would lead to fewer error messages reaching clients. Per discussion with Kyotaro HORIGUCHI and Heikki Linnakangas Discussion: 20140927191243.GD5423@alap3.anarazel.de
2015-02-03Introduce and use infrastructure for interrupt processing during client reads.Andres Freund
Up to now large swathes of backend code ran inside signal handlers while reading commands from the client, to allow for speedy reaction to asynchronous events. Most prominently shared invalidation and NOTIFY handling. That means that complex code like the starting/stopping of transactions is run in signal handlers... The required code was fragile and verbose, and is likely to contain bugs. That approach also severely limited what could be done while communicating with the client. As the read might be from within openssl it wasn't safely possible to trigger an error, e.g. to cancel a backend in idle-in-transaction state. We did that in some cases, namely fatal errors, nonetheless. Now that FE/BE communication in the backend employs non-blocking sockets and latches to block, we can quite simply interrupt reads from signal handlers by setting the latch. That allows us to signal an interrupted read, which is supposed to be retried after returning from within the ssl library. As signal handlers now only need to set the latch to guarantee timely interrupt processing, remove a fair amount of complicated & fragile code from async.c and sinval.c. We could now actually start to process some kinds of interrupts, like sinval ones, more often that before, but that seems better done separately. This work will hopefully allow to handle cases like being blocked by sending data, interrupting idle transactions and similar to be implemented without too much effort. In addition to allowing getting rid of ImmediateInterruptOK, that is. Author: Andres Freund Reviewed-By: Heikki Linnakangas
2015-02-02Add new function BackgroundWorkerInitializeConnectionByOid.Robert Haas
Sometimes it's useful for a background worker to be able to initialize its database connection by OID rather than by name, so provide a way to do that.
2015-02-02Be more careful to not lose sync in the FE/BE protocol.Heikki Linnakangas
If any error occurred while we were in the middle of reading a protocol message from the client, we could lose sync, and incorrectly try to interpret a part of another message as a new protocol message. That will usually lead to an "invalid frontend message" error that terminates the connection. However, this is a security issue because an attacker might be able to deliberately cause an error, inject a Query message in what's supposed to be just user data, and have the server execute it. We were quite careful to not have CHECK_FOR_INTERRUPTS() calls or other operations that could ereport(ERROR) in the middle of processing a message, but a query cancel interrupt or statement timeout could nevertheless cause it to happen. Also, the V2 fastpath and COPY handling were not so careful. It's very difficult to recover in the V2 COPY protocol, so we will just terminate the connection on error. In practice, that's what happened previously anyway, as we lost protocol sync. To fix, add a new variable in pqcomm.c, PqCommReadingMsg, that is set whenever we're in the middle of reading a message. When it's set, we cannot safely ERROR out and continue running, because we might've read only part of a message. PqCommReadingMsg acts somewhat similarly to critical sections in that if an error occurs while it's set, the error handler will force the connection to be terminated, as if the error was FATAL. It's not implemented by promoting ERROR to FATAL in elog.c, like ERROR is promoted to PANIC in critical sections, because we want to be able to use PG_TRY/CATCH to recover and regain protocol sync. pq_getmessage() takes advantage of that to prevent an OOM error from terminating the connection. To prevent unnecessary connection terminations, add a holdoff mechanism similar to HOLD/RESUME_INTERRUPTS() that can be used hold off query cancel interrupts, but still allow die interrupts. The rules on which interrupts are processed when are now a bit more complicated, so refactor ProcessInterrupts() and the calls to it in signal handlers so that the signal handlers always call it if ImmediateInterruptOK is set, and ProcessInterrupts() can decide to not do anything if the other conditions are not met. Reported by Emil Lenngren. Patch reviewed by Noah Misch and Andres Freund. Backpatch to all supported versions. Security: CVE-2015-0244
2015-01-14Add a default local latch for use in signal handlers.Andres Freund
To do so, move InitializeLatchSupport() into the new common process initialization functions, and add a new global variable MyLatch. MyLatch is usable as soon InitPostmasterChild() has been called (i.e. very early during startup). Initially it points to a process local latch that exists in all processes. InitProcess/InitAuxiliaryProcess then replaces that local latch with PGPROC->procLatch. During shutdown the reverse happens. This is primarily advantageous for two reasons: For one it simplifies dealing with the shared process latch, especially in signal handlers, because instead of having to check for MyProc, MyLatch can be used unconditionally. For another, a later patch that makes FEs/BE communication use latches, now can rely on the existence of a latch, even before having gone through InitProcess. Discussion: 20140927191243.GD5423@alap3.anarazel.de
2015-01-14Commonalize process startup code.Andres Freund
Move common code, that was duplicated in every postmaster child/every standalone process, into two functions in miscinit.c. Not only does that already result in a fair amount of net code reduction but it also makes it much easier to remove more duplication in the future. The prime motivation wasn't code deduplication though, but easier addition of new common code.
2015-01-06Update copyright for 2015Bruce Momjian
Backpatch certain files through 9.0
2014-12-23get_object_address: separate domain constraints from table constraintsAlvaro Herrera
Apart from enabling comments on domain constraints, this enables a future project to replicate object dropping to remote servers: with the current mechanism there's no way to distinguish between the two types of constraints, so there's no way to know what to drop. Also added support for the domain constraint comments in psql's \dd and pg_dump. Catalog version bumped due to the change in ObjectType enum.
2014-12-09REINDEX SCHEMASimon Riggs
Add new SCHEMA option to REINDEX and reindexdb. Sawada Masahiko Reviewed by Michael Paquier and Fabrízio de Royes Mello
2014-11-12Explicitly support the case that a plancache's raw_parse_tree is NULL.Tom Lane
This only happens if a client issues a Parse message with an empty query string, which is a bit odd; but since it is explicitly called out as legal by our FE/BE protocol spec, we'd probably better continue to allow it. Fix by adding tests everywhere that the raw_parse_tree field is passed to functions that don't or shouldn't accept NULL. Also make it clear in the relevant comments that NULL is an expected case. This reverts commits a73c9dbab0165b3395dfe8a44a7dfd16166963c4 and 2e9650cbcff8c8fb0d9ef807c73a44f241822eee, which fixed specific crash symptoms by hacking things at what now seems to be the wrong end, ie the callee functions. Making the callees allow NULL is superficially more robust, but it's not always true that there is a defensible thing for the callee to do in such cases. The caller has more context and is better able to decide what the empty-query case ought to do. Per followup discussion of bug #11335. Back-patch to 9.2. The code before that is sufficiently different that it would require development of a separate patch, which doesn't seem worthwhile for what is believed to be an essentially cosmetic change.
2014-11-06Move the backup-block logic from XLogInsert to a new file, xloginsert.c.Heikki Linnakangas
xlog.c is huge, this makes it a little bit smaller, which is nice. Functions related to putting together the WAL record are in xloginsert.c, and the lower level stuff for managing WAL buffers and such are in xlog.c. Also move the definition of XLogRecord to a separate header file. This causes churn in the #includes of all the files that write WAL records, and redo routines, but it avoids pulling in xlog.h into most places. Reviewed by Michael Paquier, Alvaro Herrera, Andres Freund and Amit Kapila.
2014-09-22Log ALTER SYSTEM statements as DDLStephen Frost
Per discussion in bug #11350, log ALTER SYSTEM commands at the log_statement=ddl level, rather than at the log_statement=all level. Pointed out by Tomonari Katsumata. Back-patch to 9.4 where ALTER SYSTEM was introduced.
2014-09-19Row-Level Security Policies (RLS)Stephen Frost
Building on the updatable security-barrier views work, add the ability to define policies on tables to limit the set of rows which are returned from a query and which are allowed to be added to a table. Expressions defined by the policy for filtering are added to the security barrier quals of the query, while expressions defined to check records being added to a table are added to the with-check options of the query. New top-level commands are CREATE/ALTER/DROP POLICY and are controlled by the table owner. Row Security is able to be enabled and disabled by the owner on a per-table basis using ALTER TABLE .. ENABLE/DISABLE ROW SECURITY. Per discussion, ROW SECURITY is disabled on tables by default and must be enabled for policies on the table to be used. If no policies exist on a table with ROW SECURITY enabled, a default-deny policy is used and no records will be visible. By default, row security is applied at all times except for the table owner and the superuser. A new GUC, row_security, is added which can be set to ON, OFF, or FORCE. When set to FORCE, row security will be applied even for the table owner and superusers. When set to OFF, row security will be disabled when allowed and an error will be thrown if the user does not have rights to bypass row security. Per discussion, pg_dump sets row_security = OFF by default to ensure that exports and backups will have all data in the table or will error if there are insufficient privileges to bypass row security. A new option has been added to pg_dump, --enable-row-security, to ask pg_dump to export with row security enabled. A new role capability, BYPASSRLS, which can only be set by the superuser, is added to allow other users to be able to bypass row security using row_security = OFF. Many thanks to the various individuals who have helped with the design, particularly Robert Haas for his feedback. Authors include Craig Ringer, KaiGai Kohei, Adam Brightwell, Dean Rasheed, with additional changes and rework by me. Reviewers have included all of the above, Greg Smith, Jeff McCormick, and Robert Haas.
2014-09-13Invent PGC_SU_BACKEND and mark log_connections/log_disconnections that way.Tom Lane
This new GUC context option allows GUC parameters to have the combined properties of PGC_BACKEND and PGC_SUSET, ie, they don't change after session start and non-superusers can't change them. This is a more appropriate choice for log_connections and log_disconnections than their previous context of PGC_BACKEND, because we don't want non-superusers to be able to affect whether their sessions get logged. Note: the behavior for log_connections is still a bit odd, in that when a superuser attempts to set it from PGOPTIONS, the setting takes effect but it's too late to enable or suppress connection startup logging. It's debatable whether that's worth fixing, and in any case there is a reasonable argument for PGC_SU_BACKEND to exist. In passing, re-pgindent the files touched by this commit. Fujii Masao, reviewed by Joe Conway and Amit Kapila
2014-09-09Move ALTER ... ALL IN to ProcessUtilitySlowStephen Frost
Now that ALTER TABLE .. ALL IN TABLESPACE has replaced the previous ALTER TABLESPACE approach, it makes sense to move the calls down in to ProcessUtilitySlow where the rest of ALTER TABLE is handled. This also means that event triggers will support ALTER TABLE .. ALL (which was the impetus for the original change, though it has other good qualities also). Álvaro Herrera Back-patch to 9.4 as the original rework was.
2014-09-05Fix segmentation fault that an empty prepared statement could cause.Fujii Masao
Back-patch to all supported branches. Per bug #11335 from Haruka Takatsuka