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* Be more rigorous about local variables in PostgresMain().Tom Lane2023-07-10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Since PostgresMain calls sigsetjmp, any local variables that are not marked "volatile" have a risk of unspecified behavior. In practice this means that when control returns via longjmp, such variables might get reset to their values as of the time of sigsetjmp, depending on whether the compiler chose to put them in registers or on the stack. We were careful about this for "send_ready_for_query", but not the other local variables. In the case of the timeout_enabled flags, resetting them to their initial "false" states is actually good, since we do "disable_all_timeouts()" in the longjmp cleanup code path. If that does not happen, we risk uselessly calling "disable_timeout()" later, which is harmless but a little bit expensive. Let's explicitly reset these flags so that the behavior is correct and platform-independent. (This change means that we really don't need the new "volatile" markings after all, but let's install them anyway since any change in this logic could re-introduce a problem.) There is no issue for "firstchar" and "input_message" because those are explicitly reinitialized each time through the query processing loop. To make that clearer, move them to be declared inside the loop. That leaves us with all the function-lifespan locals except the sigjmp_buf itself marked as volatile, which seems like a good policy to have going forward. Because of the possibility of extra disable_timeout() calls, this seems worth back-patching. Sergey Shinderuk and Tom Lane Discussion: https://postgr.es/m/2eda015b-7dff-47fd-d5e2-f1a9899b90a6@postgrespro.ru
* Rethink handling of [Prevent|Is]InTransactionBlock in pipeline mode.Tom Lane2022-12-13
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commits f92944137 et al. made IsInTransactionBlock() set the XACT_FLAGS_NEEDIMMEDIATECOMMIT flag before returning "false", on the grounds that that kept its API promises equivalent to those of PreventInTransactionBlock(). This turns out to be a bad idea though, because it allows an ANALYZE in a pipelined series of commands to cause an immediate commit, which is unexpected. Furthermore, if we return "false" then we have another issue, which is that ANALYZE will decide it's allowed to do internal commit-and-start-transaction sequences, thus possibly unexpectedly committing the effects of previous commands in the pipeline. To fix the latter situation, invent another transaction state flag XACT_FLAGS_PIPELINING, which explicitly records the fact that we have executed some extended-protocol command and not yet seen a commit for it. Then, require that flag to not be set before allowing InTransactionBlock() to return "false". Having done that, we can remove its setting of NEEDIMMEDIATECOMMIT without fear of causing problems. This means that the API guarantees of IsInTransactionBlock now diverge from PreventInTransactionBlock, which is mildly annoying, but it seems OK given the very limited usage of IsInTransactionBlock. (In any case, a caller preferring the old behavior could always set NEEDIMMEDIATECOMMIT for itself.) For consistency also require XACT_FLAGS_PIPELINING to not be set in PreventInTransactionBlock. This too is meant to prevent commands such as CREATE DATABASE from silently committing previous commands in a pipeline. Per report from Peter Eisentraut. As before, back-patch to all supported branches (which sadly no longer includes v10). Discussion: https://postgr.es/m/65a899dd-aebc-f667-1d0a-abb89ff3abf8@enterprisedb.com
* Force immediate commit after CREATE DATABASE etc in extended protocol.Tom Lane2022-07-26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We have a few commands that "can't run in a transaction block", meaning that if they complete their processing but then we fail to COMMIT, we'll be left with inconsistent on-disk state. However, the existing defenses for this are only watertight for simple query protocol. In extended protocol, we didn't commit until receiving a Sync message. Since the client is allowed to issue another command instead of Sync, we're in trouble if that command fails or is an explicit ROLLBACK. In any case, sitting in an inconsistent state while waiting for a client message that might not come seems pretty risky. This case wasn't reachable via libpq before we introduced pipeline mode, but it's always been an intended aspect of extended query protocol, and likely there are other clients that could reach it before. To fix, set a flag in PreventInTransactionBlock that tells exec_execute_message to force an immediate commit. This seems to be the approach that does least damage to existing working cases while still preventing the undesirable outcomes. While here, add some documentation to protocol.sgml that explicitly says how to use pipelining. That's latent in the existing docs if you know what to look for, but it's better to spell it out; and it provides a place to document this new behavior. Per bug #17434 from Yugo Nagata. It's been wrong for ages, so back-patch to all supported branches. Discussion: https://postgr.es/m/17434-d9f7a064ce2a88a3@postgresql.org
* Fix SPI's handling of errors during transaction commit.Tom Lane2022-06-22
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | SPI_commit previously left it up to the caller to recover from any error occurring during commit. Since that's complicated and requires use of low-level xact.c facilities, it's not too surprising that no caller got it right. Let's move the responsibility for cleanup into spi.c. Doing that requires redefining SPI_commit as starting a new transaction, so that it becomes equivalent to SPI_commit_and_chain except that you get default transaction characteristics instead of preserving the prior transaction's characteristics. We can make this pretty transparent API-wise by redefining SPI_start_transaction() as a no-op. Callers that expect to do something in between might be surprised, but available evidence is that no callers do so. Having made that API redefinition, we can fix this mess by having SPI_commit[_and_chain] trap errors and start a new, clean transaction before re-throwing the error. Likewise for SPI_rollback[_and_chain]. Some cleanup is also needed in AtEOXact_SPI, which was nowhere near smart enough to deal with SPI contexts nested inside a committing context. While plperl and pltcl need no changes beyond removing their now-useless SPI_start_transaction() calls, plpython needs some more work because it hadn't gotten the memo about catching commit/rollback errors in the first place. Such an error resulted in longjmp'ing out of the Python interpreter, which leaks Python stack entries at present and is reported to crash Python 3.11 altogether. Add the missing logic to catch such errors and convert them into Python exceptions. This is a back-patch of commit 2e517818f. That's now aged long enough to reduce the concerns about whether it will break something, and we do need to ensure that supported branches will work with Python 3.11. Peter Eisentraut and Tom Lane Discussion: https://postgr.es/m/3375ffd8-d71c-2565-e348-a597d6e739e3@enterprisedb.com Discussion: https://postgr.es/m/17416-ed8fe5d7213d6c25@postgresql.org
* Suppress warning about stack_base_ptr with late-model GCC.Tom Lane2022-02-17
| | | | | | | | | | | | | | | | | | | | GCC 12 complains that set_stack_base is storing the address of a local variable in a long-lived pointer. This is an entirely reasonable warning (indeed, it just helped us find a bug); but that behavior is intentional here. We can work around it by using __builtin_frame_address(0) instead of a specific local variable; that produces an address a dozen or so bytes different, in my testing, but we don't care about such a small difference. Maybe someday a compiler lacking that function will start to issue a similar warning, but we'll worry about that when it happens. Patch by me, per a suggestion from Andres Freund. Back-patch to v12, which is as far back as the patch will go without some pain. (Recently-established project policy would permit a back-patch as far as 9.2, but I'm disinclined to expend the work until GCC 12 is much more widespread.) Discussion: https://postgr.es/m/3773792.1645141467@sss.pgh.pa.us
* Refactor CHECK_FOR_INTERRUPTS() to add flexibility.Tom Lane2021-05-14
| | | | | | | | | | | | | | | | | | | | Split up CHECK_FOR_INTERRUPTS() to provide an additional macro INTERRUPTS_PENDING_CONDITION(), which just tests whether an interrupt is pending without attempting to service it. This is useful in situations where the caller knows that interrupts are blocked, and would like to find out if it's worth the trouble to unblock them. Also add INTERRUPTS_CAN_BE_PROCESSED(), which indicates whether CHECK_FOR_INTERRUPTS() can be relied on to clear the pending interrupt. This commit doesn't actually add any uses of the new macros, but a follow-on bug fix will do so. Back-patch to all supported branches to provide infrastructure for that fix. Alvaro Herrera and Tom Lane Discussion: https://postgr.es/m/20210513155351.GA7848@alvherre.pgsql
* Further second thoughts about idle_session_timeout patch.Tom Lane2021-01-07
| | | | | | | | | | | On reflection, the order of operations in PostgresMain() is wrong. These timeouts ought to be shut down before, not after, we do the post-command-read CHECK_FOR_INTERRUPTS, to guarantee that any timeout error will be detected there rather than at some ill-defined later point (possibly after having wasted a lot of work). This is really an error in the original idle_in_transaction_timeout patch, so back-patch to 9.6 where that was introduced.
* Detect the deadlocks between backends and the startup process.Fujii Masao2021-01-06
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The deadlocks that the recovery conflict on lock is involved in can happen between hot-standby backends and the startup process. If a backend takes an access exclusive lock on the table and which finally triggers the deadlock, that deadlock can be detected as expected. On the other hand, previously, if the startup process took an access exclusive lock and which finally triggered the deadlock, that deadlock could not be detected and could remain even after deadlock_timeout passed. This is a bug. The cause of this bug was that the code for handling the recovery conflict on lock didn't take care of deadlock case at all. It assumed that deadlocks involving the startup process and backends were able to be detected by the deadlock detector invoked within backends. But this assumption was incorrect. The startup process also should have invoked the deadlock detector if necessary. To fix this bug, this commit makes the startup process invoke the deadlock detector if deadlock_timeout is reached while handling the recovery conflict on lock. Specifically, in that case, the startup process requests all the backends holding the conflicting locks to check themselves for deadlocks. Back-patch to v9.6. v9.5 has also this bug, but per discussion we decided not to back-patch the fix to v9.5. Because v9.5 doesn't have some infrastructure codes (e.g., 37c54863cf) that this bug fix patch depends on. We can apply those codes for the back-patch, but since the next minor version release is the final one for v9.5, it's risky to do that. If we unexpectedly introduce new bug to v9.5 by the back-patch, there is no chance to fix that. We determined that the back-patch to v9.5 would give more risk than gain. Author: Fujii Masao Reviewed-by: Bertrand Drouvot, Masahiko Sawada, Kyotaro Horiguchi Discussion: https://postgr.es/m/4041d6b6-cf24-a120-36fa-1294220f8243@oss.nttdata.com
* Re-implement the ereport() macro using __VA_ARGS__.Tom Lane2020-03-24
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Now that we require C99, we can depend on __VA_ARGS__ to work, and revising ereport() to use it has several significant benefits: * The extra parentheses around the auxiliary function calls are now optional. Aside from being a bit less ugly, this removes a common gotcha for new contributors, because in some cases the compiler errors you got from forgetting them were unintelligible. * The auxiliary function calls are now evaluated as a comma expression list rather than as extra arguments to errfinish(). This means that compilers can be expected to warn about no-op expressions in the list, allowing detection of several other common mistakes such as forgetting to add errmsg(...) when converting an elog() call to ereport(). * Unlike the situation with extra function arguments, comma expressions are guaranteed to be evaluated left-to-right, so this removes platform dependency in the order of the auxiliary function calls. While that dependency hasn't caused us big problems in the past, this change does allow dropping some rather shaky assumptions around errcontext() domain handling. There's no intention to make wholesale changes of existing ereport calls, but as proof-of-concept this patch removes the extra parens from a couple of calls in postgres.c. While new code can be written either way, code intended to be back-patched will need to use extra parens for awhile yet. It seems worth back-patching this change into v12, so as to reduce the window where we have to be careful about that by one year. Hence, this patch is careful to preserve ABI compatibility; a followup HEAD-only patch will make some additional simplifications. Andres Freund and Tom Lane Discussion: https://postgr.es/m/CA+fd4k6N8EjNvZpM8nme+y+05mz-SM8Z_BgkixzkA34R+ej0Kw@mail.gmail.com
* Stabilize NOTIFY behavior by transmitting notifies before ReadyForQuery.Tom Lane2019-11-24
| | | | | | | | | | | | | | | | | | | | | | This patch ensures that, if any notify messages were received during a just-finished transaction, they get sent to the frontend just before not just after the ReadyForQuery message. With libpq and other client libraries that act similarly, this guarantees that the client will see the notify messages as available as soon as it thinks the transaction is done. This probably makes no difference in practice, since in realistic use-cases the application would have to cope with asynchronous arrival of notify events anyhow. However, it makes it a lot easier to build cross-session-notify test cases with stable behavior. I'm a bit surprised now that we've not seen any buildfarm instability with the test cases added by commit b10f40bf0. Tests that I intend to add in an upcoming bug fix are definitely unstable without this. Back-patch to 9.6, which is as far back as we can do NOTIFY testing with the isolationtester infrastructure. Discussion: https://postgr.es/m/13881.1574557302@sss.pgh.pa.us
* Revert "Add log_statement_sample_rate parameter"Tomas Vondra2019-08-04
| | | | | | | | | | | | | | This reverts commit 88bdbd3f746049834ae3cc972e6e650586ec3c9d. As committed, statement sampling used the existing duration threshold (log_min_duration_statement) when decide which statements to sample. The issue is that even the longest statements are subject to sampling, and so may not end up logged. An improvement was proposed, introducing a second duration threshold, but it would not be backwards compatible. So we've decided to revert this feature - the separate threshold should be part of the feature itself. Discussion: https://postgr.es/m/CAFj8pRDS8tQ3Wviw9%3DAvODyUciPSrGeMhJi_WPE%2BEB8%2B4gLL-Q%40mail.gmail.com
* Revert "Silence compiler warning"Tomas Vondra2019-08-04
| | | | | | | | | | | | | | This reverts commit 9dc122585551516309c9362e673effdbf3bd79bd. As committed, statement sampling used the existing duration threshold (log_min_duration_statement) when decide which statements to sample. The issue is that even the longest statements are subject to sampling, and so may not end up logged. An improvement was proposed, introducing a second duration threshold, but it would not be backwards compatible. So we've decided to revert this feature - the separate threshold should be part of the feature itself. Discussion: https://postgr.es/m/CAFj8pRDS8tQ3Wviw9%3DAvODyUciPSrGeMhJi_WPE%2BEB8%2B4gLL-Q%40mail.gmail.com
* Log all statements from a sample of transactionsAlvaro Herrera2019-04-03
| | | | | | | | This is useful to obtain a view of the different transaction types in an application, regardless of the durations of the statements each runs. Author: Adrien Nayrat Reviewed-by: Masahiko Sawada, Hayato Kuroda, Andres Freund
* Refactor ParamListInfo initializationPeter Eisentraut2019-03-14
| | | | | There were six copies of identical nontrivial code. Put it into a function.
* More unconstify usePeter Eisentraut2019-02-13
| | | | | | | Replace casts whose only purpose is to cast away const with the unconstify() macro. Discussion: https://www.postgresql.org/message-id/flat/53a28052-f9f3-1808-fed9-460fd43035ab%402ndquadrant.com
* Refactor planner's header files.Tom Lane2019-01-29
| | | | | | | | | | | | | | | | | | | | | | | | Create a new header optimizer/optimizer.h, which exposes just the planner functions that can be used "at arm's length", without need to access Paths or the other planner-internal data structures defined in nodes/relation.h. This is intended to provide the whole planner API seen by most of the rest of the system; although FDWs still need to use additional stuff, and more thought is also needed about just what selfuncs.c should rely on. The main point of doing this now is to limit the amount of new #include baggage that will be needed by "planner support functions", which I expect to introduce later, and which will be in relevant datatype modules rather than anywhere near the planner. This commit just moves relevant declarations into optimizer.h from other header files (a couple of which go away because everything got moved), and adjusts #include lists to match. There's further cleanup that could be done if we want to decide that some stuff being exposed by optimizer.h doesn't belong in the planner at all, but I'll leave that for another day. Discussion: https://postgr.es/m/11460.1548706639@sss.pgh.pa.us
* Fix misc typos in comments.Heikki Linnakangas2019-01-23
| | | | | | Spotted mostly by Fabien Coelho. Discussion: https://www.postgresql.org/message-id/alpine.DEB.2.21.1901230947050.16643@lancre
* Update copyright for 2019Bruce Momjian2019-01-02
| | | | Backpatch-through: certain files through 9.4
* Silence compiler warningAlvaro Herrera2018-11-30
| | | | | | | My original coding was questionable anyway. Reported-by: Sergei Kornilov Discussion: https://postgr.es/m/9645101543575886@myt6-27270b78ac4f.qloud-c.yandex.net
* Add log_statement_sample_rate parameterAlvaro Herrera2018-11-29
| | | | | | | | | | This allows to set a lower log_min_duration_statement value without incurring excessive log traffic (which reduces performance). This can be useful to analyze workloads with lots of short queries. Author: Adrien Nayrat Reviewed-by: David Rowley, Vik Fearing Discussion: https://postgr.es/m/c30ee535-ee1e-db9f-fa97-146b9f62caed@anayrat.info
* Server-side fix for delayed NOTIFY and SIGTERM processing.Tom Lane2018-10-19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | 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
* 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 a debugging option to stress-test outfuncs.c and readfuncs.c.Tom Lane2018-09-18
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In the normal course of operation, query trees will be serialized only if they are stored as views or rules; and plan trees will be serialized only if they get passed to parallel-query workers. This leaves an awful lot of opportunity for bugs/oversights to not get detected, as indeed we've just been reminded of the hard way. To improve matters, this patch adds a new compile option WRITE_READ_PARSE_PLAN_TREES, which is modeled on the longstanding option COPY_PARSE_PLAN_TREES; but instead of passing all parse and plan trees through copyObject, it passes them through nodeToString + stringToNode. Enabling this option in a buildfarm animal or two will catch problems at least for cases that are exercised by the regression tests. A small problem with this idea is that readfuncs.c historically has discarded location fields, on the reasonable grounds that parse locations in a retrieved view are not relevant to the current query. But doing that in WRITE_READ_PARSE_PLAN_TREES breaks pg_stat_statements, and it could cause problems for future improvements that might try to report error locations at runtime. To fix that, provide a variant behavior in readfuncs.c that makes it restore location fields when told to. In passing, const-ify the string arguments of stringToNode and its subsidiary functions, just because it annoyed me that they weren't const already. Discussion: https://postgr.es/m/17114.1537138992@sss.pgh.pa.us
* Introduce minimal C99 usage to verify compiler support.Andres Freund2018-08-23
| | | | | | | | | This just converts a few for loops in postgres.c to declare variables in the loop initializer, and uses designated initializers in smgr.c's definition of smgr callbacks. Author: Andres Freund Discussion: https://postgr.es/m/97d4b165-192d-3605-749c-f614a0c4e783@2ndquadrant.com
* Don't run atexit callbacks in quickdie signal handlers.Heikki Linnakangas2018-08-08
| | | | | | | | | | | | | | | | | 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
* Fix SPI error cleanup and memory leakPeter Eisentraut2018-05-03
| | | | | | | | | | | | Since the SPI stack has been moved from TopTransactionContext to TopMemoryContext, setting _SPI_stack to NULL in AtEOXact_SPI() leaks memory. In fact, we don't need to do that anymore: We just leave the allocated stack around for the next SPI use. Also, refactor the SPI cleanup so that it is run both at transaction end and when returning to the main loop on an exception. The latter is necessary when a procedure calls a COMMIT or ROLLBACK command that itself causes an error.
* Clean up warnings from -Wimplicit-fallthrough.Tom Lane2018-05-01
| | | | | | | | | | | | | | | | | | | | | | | | | Recent gcc can warn about switch-case fall throughs that are not explicitly labeled as intentional. This seems like a good thing, so clean up the warnings exposed thereby by labeling all such cases with comments that gcc will recognize. In files that already had one or more suitable comments, I generally matched the existing style of those. Otherwise I went with /* FALLTHROUGH */, which is one of the spellings approved at the more-restrictive-than-default level -Wimplicit-fallthrough=4. (At the default level you can also spell it /* FALL ?THRU */, and it's not picky about case. What you can't do is include additional text in the same comment, so some existing comments containing versions of this aren't good enough.) Testing with gcc 8.0.1 (Fedora 28's current version), I found that I also had to put explicit "break"s after elog(ERROR) or ereport(ERROR); apparently, for this purpose gcc doesn't recognize that those don't return. That seems like possibly a gcc bug, but it's fine because in most places we did that anyway; so this amounts to a visit from the style police. Discussion: https://postgr.es/m/15083.1525207729@sss.pgh.pa.us
* Allow group access on PGDATAStephen Frost2018-04-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | Allow the cluster to be optionally init'd with read access for the group. This means a relatively non-privileged user can perform a backup of the cluster without requiring write privileges, which enhances security. The mode of PGDATA is used to determine whether group permissions are enabled for directory and file creates. This method was chosen as it's simple and works well for the various utilities that write into PGDATA. Changing the mode of PGDATA manually will not automatically change the mode of all the files contained therein. If the user would like to enable group access on an existing cluster then changing the mode of all the existing files will be required. Note that pg_upgrade will automatically change the mode of all migrated files if the new cluster is init'd with the -g option. Tests are included for the backend and all the utilities which operate on the PG data directory to ensure that the correct mode is set based on the data directory permissions. Author: David Steele <david@pgmasters.net> Reviewed-By: Michael Paquier, with discussion amongst many others. Discussion: https://postgr.es/m/ad346fe6-b23e-59f1-ecb7-0e08390ad629%40pgmasters.net
* Allow background workers to bypass datallowconnMagnus Hagander2018-04-05
| | | | | | | THis adds a "flags" field to the BackgroundWorkerInitializeConnection() and BackgroundWorkerInitializeConnectionByOid(). For now only one flag, BGWORKER_BYPASS_ALLOWCONN, is defined, which allows the worker to ignore datallowconn.
* Allow committing inside cursor loopPeter Eisentraut2018-03-28
| | | | | | | | | | | | | | | Previously, committing or aborting inside a cursor loop was prohibited because that would close and remove the cursor. To allow that, automatically convert such cursors to holdable cursors so they survive commits or rollbacks. Portals now have a new state "auto-held", which means they have been converted automatically from pinned. An auto-held portal is kept on transaction commit or rollback, but is still removed when returning to the main loop on error. This supports all languages that have cursor loop constructs: PL/pgSQL, PL/Python, PL/Perl. Reviewed-by: Ildus Kurbangaliev <i.kurbangaliev@postgrespro.ru>
* Basic JIT provider and error handling infrastructure.Andres Freund2018-03-21
| | | | | | | | | | | | | | | | | | | | This commit introduces: 1) JIT provider abstraction, which allows JIT functionality to be implemented in separate shared libraries. That's desirable because it allows to install JIT support as a separate package, and because it allows experimentation with different forms of JITing. 2) JITContexts which can be, using functions introduced in follow up commits, used to emit JITed functions, and have them be cleaned up on error. 3) The outline of a LLVM JIT provider, which will be fleshed out in subsequent commits. Documentation for GUCs added, and for JIT in general, will be added in later commits. Author: Andres Freund, with architectural input from Jeff Davis Discussion: https://postgr.es/m/20170901064131.tazjxwus3k2w3ybh@alap3.anarazel.de
* Clear stmt_timeout_active if we disable_all_timeouts.Robert Haas2018-02-09
| | | | | | | | | | | Otherwise, we can end up with the flag set when the timeout is actually disabled, leading to misbehavior. Commit f8e5f156b30efee5d0038b03e38735773abcb7ed introduced this bug. Reported by Peter Eisentraut. Analysis and fix by Thomas Munro, tweaked by me. Discussion: http://postgr.es/m/6a909374-2602-7136-8c70-397330a418f3@2ndquadrant.com
* Update portal-related memory context names and APIPeter Eisentraut2018-01-09
| | | | | | | | | | | | | Rename PortalMemory to TopPortalContext, to avoid confusion with PortalContext and align naming with similar top-level memory contexts. Rename PortalData's "heap" field to portalContext. The "heap" naming seems quite antiquated and confusing. Also get rid of the PortalGetHeapMemory() macro and access the field directly, which we do for other portal fields, so this abstraction doesn't buy anything. Reviewed-by: Andrew Dunstan <andrew.dunstan@2ndquadrant.com> Reviewed-by: Alvaro Herrera <alvherre@alvh.no-ip.org>
* Update copyright for 2018Bruce Momjian2018-01-02
| | | | Backpatch-through: certain files through 9.3
* Rearrange execution of PARAM_EXTERN Params for plpgsql's benefit.Tom Lane2017-12-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch does three interrelated things: * Create a new expression execution step type EEOP_PARAM_CALLBACK and add the infrastructure needed for add-on modules to generate that. As discussed, the best control mechanism for that seems to be to add another hook function to ParamListInfo, which will be called by ExecInitExpr if it's supplied and a PARAM_EXTERN Param is found. For stand-alone expressions, we add a new entry point to allow the ParamListInfo to be specified directly, since it can't be retrieved from the parent plan node's EState. * Redesign the API for the ParamListInfo paramFetch hook so that the ParamExternData array can be entirely virtual. This also lets us get rid of ParamListInfo.paramMask, instead leaving it to the paramFetch hook to decide which param IDs should be accessible or not. plpgsql_param_fetch was already doing the identical masking check, so having callers do it too seemed redundant. While I was at it, I added a "speculative" flag to paramFetch that the planner can specify as TRUE to avoid unwanted failures. This solves an ancient problem for plpgsql that it couldn't provide values of non-DTYPE_VAR variables to the planner for fear of triggering premature "record not assigned yet" or "field not found" errors during planning. * Rework plpgsql to get rid of the need for "unshared" parameter lists, by dint of turning the single ParamListInfo per estate into a nearly read-only data structure that doesn't instantiate any per-variable data. Instead, the paramFetch hook controls access to per-variable data and can make the right decisions on the fly, replacing the cases that we used to need multiple ParamListInfos for. This might perhaps have been a performance loss on its own, but by using a paramCompile hook we can bypass plpgsql_param_fetch entirely during normal query execution. (It's now only called when, eg, we copy the ParamListInfo into a cursor portal. copyParamList() or SerializeParamList() effectively instantiate the virtual parameter array as a simple physical array without a paramFetch hook, which is what we want in those cases.) This allows reverting most of commit 6c82d8d1f, though I kept the cosmetic code-consolidation aspects of that (eg the assign_simple_var function). Performance testing shows this to be at worst a break-even change, and it can provide wins ranging up to 20% in test cases involving accesses to fields of "record" variables. The fact that values of such variables can now be exposed to the planner might produce wins in some situations, too, but I've not pursued that angle. In passing, remove the "parent" pointer from the arguments to ExecInitExprRec and related functions, instead storing that pointer in a transient field in ExprState. The ParamListInfo pointer for a stand-alone expression is handled the same way; we'd otherwise have had to add yet another recursively-passed-down argument in expression compilation. Discussion: https://postgr.es/m/32589.1513706441@sss.pgh.pa.us
* Update typedefs.list and re-run pgindentRobert Haas2017-11-29
| | | | Discussion: http://postgr.es/m/CA+TgmoaA9=1RWKtBWpDaj+sF3Stgc8sHgf5z=KGtbjwPLQVDMA@mail.gmail.com
* Back out the session_start and session_end hooks feature.Andrew Dunstan2017-11-16
| | | | | | | | | | It's become apparent during testing that there are problems with at least the testing regime. I don't think we should have it without a working test regime, and the difficulties might indicate implementation problems anyway, so I'm backing out the whole thing until that's sorted out. This reverts commits 7459484 9989f92 cd8ce3a
* Add hooks for session start and session endAndrew Dunstan2017-11-15
| | | | | | | | | | These hooks can be used in loadable modules. A simple test module is included. Discussion: https://postgr.es/m/20170720204733.40f2b7eb.nagata@sraoss.co.jp Fabrízio de Royes Mello and Yugo Nagata Reviewed by Michael Paquier and Aleksandr Parfenov
* Change TRUE/FALSE to true/falsePeter Eisentraut2017-11-08
| | | | | | | | | | | | | | The lower case spellings are C and C++ standard and are used in most parts of the PostgreSQL sources. The upper case spellings are only used in some files/modules. So standardize on the standard spellings. The APIs for ICU, Perl, and Windows define their own TRUE and FALSE, so those are left as is when using those APIs. In code comments, we use the lower-case spelling for the C concepts and keep the upper-case spelling for the SQL concepts. Reviewed-by: Michael Paquier <michael.paquier@gmail.com>
* Replace remaining uses of pq_sendint with pq_sendint{8,16,32}.Andres Freund2017-10-11
| | | | | | | pq_sendint() remains, so extension code doesn't unnecessarily break. Author: Andres Freund Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de
* Improve performance of SendRowDescriptionMessage.Andres Freund2017-10-11
| | | | | | | | | | | | | | | There's three categories of changes leading to better performance: - Splitting the per-attribute part of SendRowDescriptionMessage into a v2 and a v3 version allows avoiding branches for every attribute. - Preallocating the size of the buffer to be big enough for all attributes and then using pq_write* avoids unnecessary buffer size checks & resizing. - Reusing a persistently allocated StringInfo for all SendRowDescriptionMessage() invocations avoids repeated allocations & reallocations. Author: Andres Freund Discussion: https://postgr.es/m/20170914063418.sckdzgjfrsbekae4@alap3.anarazel.de
* Prevent idle in transaction session timeout from sometimes being ignored.Andres Freund2017-10-11
| | | | | | | | | | | | | | | | | | | | | | | The previous coding in ProcessInterrupts() could lead to idle_in_transaction_session_timeout being ignored, when statement_timeout occurred earlier. The problem was that ProcessInterrupts() would return before processing the transaction timeout if QueryCancelPending was set while QueryCancelHoldoffCount != 0 - which is the case when reading new commands from the client. Ergo when the idle transaction timeout would hit. Fix that by removing the early return. Alternatively the transaction timeout code could have been moved up, but that early return seems like an issue that could hit other cases too. Author: Lukas Fittl Bug: #14821 Discussion: https://www.postgresql.org/message-id/20170921010956.17345.61461%40wrigleys.postgresql.org https://www.postgresql.org/message-id/CAP53PkxQnv3OWJpyNPGJYT62uY=n1=2CF_Lpc6gVOFnc0-gazw@mail.gmail.com Backpatch: 9.6-, where idle_in_transaction_session_timeout was introduced.
* Rearm statement_timeout after each executed query.Andres Freund2017-09-18
| | | | | | | | | | | | | | | | | | Previously statement_timeout, in the extended protocol, affected all messages till a Sync message. For clients that pipeline/batch query execution that's problematic. Instead disable timeout after each Execute message, and enable, if necessary, the timer in start_xact_command(). As that's done only for Execute and not Parse / Bind, pipelining the latter two could still cause undesirable timeouts. But a survey of protocol implementations shows that all drivers issue Sync messages when preparing, and adding timeout rearming to both is fairly expensive for the common parse / bind / execute sequence. Author: Tatsuo Ishii, editorialized by Andres Freund Reviewed-By: Takayuki Tsunakawa, Andres Freund Discussion: https://postgr.es/m/20170222.115044.1665674502985097185.t-ishii@sraoss.co.jp
* Fix crash restart bug introduced in 8356753c212.Andres Freund2017-09-18
| | | | | | | | | | | | | | | | | | The bug was caused by not re-reading the control file during crash recovery restarts, which lead to an attempt to pfree() shared memory contents. The fix is to re-read the control file, which seems good anyway. It's unclear as of this moment, whether we want to keep the refactoring introduced in the commit referenced above, or come up with an alternative approach. But fixing the bug in the mean time seems like a good idea regardless. A followup commit will introduce regression test coverage for crash restarts. Reported-By: Tom Lane Discussion: https://postgr.es/m/14134.1505572349@sss.pgh.pa.us
* Perform only one ReadControlFile() during startup.Andres Freund2017-09-14
| | | | | | | | | | | | | Previously we read the control file in multiple places. But soon the segment size will be configurable and stored in the control file, and that needs to be available earlier than it currently is needed. Instead of adding yet another place where it's read, refactor things so there's a single processing of the control file during startup (in EXEC_BACKEND that's every individual backend's startup). Author: Andres Freund Discussion: http://postgr.es/m/20170913092828.aozd3gvvmw67gmyc@alap3.anarazel.de
* Reduce excessive dereferencing of function pointersPeter Eisentraut2017-09-07
| | | | | | | | | | | | It is equivalent in ANSI C to write (*funcptr) () and funcptr(). These two styles have been applied inconsistently. After discussion, we'll use the more verbose style for plain function pointer variables, to make it clear that it's a variable, and the shorter style when the function pointer is in a struct (s.func() or s->func()), because then it's clear that it's not a plain function name, and otherwise the excessive punctuation makes some of those invocations hard to read. Discussion: https://www.postgresql.org/message-id/f52c16db-14ed-757d-4b48-7ef360b1631d@2ndquadrant.com
* Fix handling of savepoint commands within multi-statement Query strings.Tom Lane2017-09-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Issuing a savepoint-related command in a Query message that contains multiple SQL statements led to a FATAL exit with a complaint about "unexpected state STARTED". This is a shortcoming of commit 4f896dac1, which attempted to prevent such misbehaviors in multi-statement strings; its quick hack of marking the individual statements as "not top-level" does the wrong thing in this case, and isn't a very accurate description of the situation anyway. To fix, let's introduce into xact.c an explicit model of what happens for multi-statement Query strings. This is an "implicit transaction block in progress" state, which for many purposes works like the normal TBLOCK_INPROGRESS state --- in particular, IsTransactionBlock returns true, causing the desired result that PreventTransactionChain will throw error. But in case of error abort it works like TBLOCK_STARTED, allowing the transaction to be cancelled without need for an explicit ROLLBACK command. Commit 4f896dac1 is reverted in toto, so that we go back to treating the individual statements as "top level". We could have left it as-is, but this allows sharpening the error message for PreventTransactionChain calls inside functions. Except for getting a normal error instead of a FATAL exit for savepoint commands, this patch should result in no user-visible behavioral change (other than that one error message rewording). There are some things we might want to do in the line of changing the appearance or wording of error and warning messages around this behavior, which would be much simpler to do now that it's an explicitly modeled state. But I haven't done them here. Although this fixes a long-standing bug, no backpatch. The consequences of the bug don't seem severe enough to justify the risk that this commit itself creates some new issue. Patch by me, but it owes something to previous investigation by Takayuki Tsunakawa, who also reported the bug in the first place. Also thanks to Michael Paquier for reviewing. Discussion: https://postgr.es/m/0A3221C70F24FB45833433255569204D1F6BE40D@G01JPEXMBYT05
* Add memory info to getrusage outputPeter Eisentraut2017-09-01
| | | | | | | | Add the maxrss field to the getrusage output (log_*_stats). This was previously omitted because of portability concerns, but we feel this might not be a concern anymore. based on patch by Justin Pryzby <pryzby@telsasoft.com>
* Phase 3 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | Don't move parenthesized lines to the left, even if that means they flow past the right margin. By default, BSD indent lines up statement continuation lines that are within parentheses so that they start just to the right of the preceding left parenthesis. However, traditionally, if that resulted in the continuation line extending to the right of the desired right margin, then indent would push it left just far enough to not overrun the margin, if it could do so without making the continuation line start to the left of the current statement indent. That makes for a weird mix of indentations unless one has been completely rigid about never violating the 80-column limit. This behavior has been pretty universally panned by Postgres developers. Hence, disable it with indent's new -lpl switch, so that parenthesized lines are always lined up with the preceding left paren. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
* Phase 2 of pgindent updates.Tom Lane2017-06-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us