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2024-03-07Revert "Fix parallel-safety check of expressions and predicate for index builds"Michael Paquier
This reverts commit eae7be600be7, following a discussion with Tom Lane, due to concerns that this impacts the decisions made by the planner for the number of workers spawned based on the inlining and const-folding of index expressions and predicate for cases that would have worked until this commit. Discussion: https://postgr.es/m/162802.1709746091@sss.pgh.pa.us Backpatch-through: 12
2024-03-06Fix parallel-safety check of expressions and predicate for index buildsMichael Paquier
As coded, the planner logic that calculates the number of parallel workers to use for a parallel index build uses expressions and predicates from the relcache, which are flattened for the planner by eval_const_expressions(). As reported in the bug, an immutable parallel-unsafe function flattened in the relcache would become a Const, which would be considered as parallel-safe, even if the predicate or the expressions including the function are not safe in parallel workers. Depending on the expressions or predicate used, this could cause the parallel build to fail. Tests are included that check parallel index builds with parallel-unsafe predicate and expressions. Two routines are added to lsyscache.h to be able to retrieve expressions and predicate of an index from its pg_index data. Reported-by: Alexander Lakhin Author: Tender Wang Reviewed-by: Jian He, Michael Paquier Discussion: https://postgr.es/m/CAHewXN=UaAaNn9ruHDH3Os8kxLVmtWqbssnf=dZN_s9=evHUFA@mail.gmail.com Backpatch-through: 12
2023-11-06Detect integer overflow while computing new array dimensions.Tom Lane
array_set_element() and related functions allow an array to be enlarged by assigning to subscripts outside the current array bounds. While these places were careful to check that the new bounds are allowable, they neglected to consider the risk of integer overflow in computing the new bounds. In edge cases, we could compute new bounds that are invalid but get past the subsequent checks, allowing bad things to happen. Memory stomps that are potentially exploitable for arbitrary code execution are possible, and so is disclosure of server memory. To fix, perform the hazardous computations using overflow-detecting arithmetic routines, which fortunately exist in all still-supported branches. The test cases added for this generate (after patching) errors that mention the value of MaxArraySize, which is platform-dependent. Rather than introduce multiple expected-files, use psql's VERBOSITY parameter to suppress the printing of the message text. v11 psql lacks that parameter, so omit the tests in that branch. Our thanks to Pedro Gallegos for reporting this problem. Security: CVE-2023-5869
2023-11-02Be more wary about NULL values for GUC string variables.Tom Lane
get_explain_guc_options() crashed if a string GUC marked GUC_EXPLAIN has a NULL boot_val. Nosing around found a couple of other places that seemed insufficiently cautious about NULL string values, although those are likely unreachable in practice. Add some commentary defining the expectations for NULL values of string variables, in hopes of forestalling future additions of more such bugs. Xing Guo, Aleksander Alekseev, Tom Lane Discussion: https://postgr.es/m/CACpMh+AyDx5YUpPaAgzVwC1d8zfOL4JoD-uyFDnNSa1z0EsDQQ@mail.gmail.com
2023-10-17Avoid calling proc_exit() in processes forked by system().Nathan Bossart
The SIGTERM handler for the startup process immediately calls proc_exit() for the duration of the restore_command, i.e., a call to system(). This system() call forks a new process to execute the shell command, and this child process inherits the parent's signal handlers. If both the parent and child processes receive SIGTERM, both will attempt to call proc_exit(). This can end badly. For example, both processes will try to remove themselves from the PGPROC shared array. To fix this problem, this commit adds a check in StartupProcShutdownHandler() to see whether MyProcPid == getpid(). If they match, this is the parent process, and we can proc_exit() like before. If they do not match, this is a child process, and we just emit a message to STDERR (in a signal safe manner) and _exit(), thereby skipping any problematic exit callbacks. This commit also adds checks in proc_exit(), ProcKill(), and AuxiliaryProcKill() that verify they are not being called within such child processes. Suggested-by: Andres Freund Reviewed-by: Thomas Munro, Andres Freund Discussion: https://postgr.es/m/Y9nGDSgIm83FHcad%40paquier.xyz Discussion: https://postgr.es/m/20230223231503.GA743455%40nathanxps13 Backpatch-through: 11
2023-01-20Make our back branches build under -fkeep-inline-functions.Tom Lane
Add "#ifndef FRONTEND" where necessary to make pg_waldump build on compilers that don't elide unused static-inline functions. This back-patches relevant parts of commit 3e9ca5260, fixing build breakage from dc7420c2c and back-patching of f10f0ae42. Per recently-resurrected buildfarm member castoroides. We aren't expecting castoroides to build anything newer than v11, but we might as well clean up the intermediate branches while at it.
2022-11-17Replace RelationOpenSmgr() with RelationGetSmgr().Tom Lane
This is a back-patch of the v15-era commit f10f0ae42 into older supported branches. The idea is to design out bugs in which an ill-timed relcache flush clears rel->rd_smgr partway through some code sequence that wasn't expecting that. We had another report today of a corner case that reliably crashes v14 under debug_discard_caches (nee CLOBBER_CACHE_ALWAYS), and therefore would crash once in a blue moon in the field. We're unlikely to get rid of all such code paths unless we adopt the more rigorous coding rules instituted by f10f0ae42. Therefore, even though this is a bit invasive, it's time to back-patch. Some comfort can be taken in the fact that f10f0ae42 has been in v15 for 16 months without problems. I left the RelationOpenSmgr macro present in the back branches, even though no core code should use it anymore, in order to not break third-party extensions in minor releases. Such extensions might opt to start using RelationGetSmgr instead, to reduce their code differential between v15 and earlier branches. This carries a hazard of failing to compile against headers from existing minor releases. However, once compiled the extension should work fine even with such releases, because RelationGetSmgr is a "static inline" function so it creates no link-time dependency. So depending on distribution practices, that might be an OK tradeoff. Per report from Spyridon Dimitrios Agathos. Original patch by Amul Sul. Discussion: https://postgr.es/m/CAFM5RaqdgyusQvmWkyPYaWMwoK5gigdtW-7HcgHgOeAw7mqJ_Q@mail.gmail.com Discussion: https://postgr.es/m/CANiYTQsU7yMFpQYnv=BrcRVqK_3U3mtAzAsJCaqtzsDHfsUbdQ@mail.gmail.com
2022-09-14Expand palloc/pg_malloc API for more type safetyPeter Eisentraut
This adds additional variants of palloc, pg_malloc, etc. that encapsulate common usage patterns and provide more type safety. Specifically, this adds palloc_object(), palloc_array(), and repalloc_array(), which take the type name of the object to be allocated as its first argument and cast the return as a pointer to that type. There are also palloc0_object() and palloc0_array() variants for initializing with zero, and pg_malloc_*() variants of all of the above. Inspired by the talloc library. This is backpatched from master so that future backpatchable code can make use of these APIs. This patch by itself does not contain any users of these APIs. Reviewed-by: Tom Lane <tgl@sss.pgh.pa.us> Discussion: https://www.postgresql.org/message-id/flat/bb755632-2a43-d523-36f8-a1e7a389a907@enterprisedb.com
2022-03-26Suppress compiler warning in relptr_store().Tom Lane
clang 13 with -Wextra warns that "performing pointer subtraction with a null pointer has undefined behavior" in the places where freepage.c tries to set a relptr variable to constant NULL. This appears to be a compiler bug, but it's unlikely to get fixed instantly. Fortunately, we can work around it by introducing an inline support function, which seems like a good change anyway because it removes the macro's existing double-evaluation hazard. Backpatch to v10 where this code was introduced. Patch by me, based on an idea of Andres Freund's. Discussion: https://postgr.es/m/48826.1648310694@sss.pgh.pa.us
2022-01-27Fix ordering of XIDs in ProcArrayApplyRecoveryInfoTomas Vondra
Commit 8431e296ea reworked ProcArrayApplyRecoveryInfo to sort XIDs before adding them to KnownAssignedXids. But the XIDs are sorted using xidComparator, which compares the XIDs simply as uint32 values, not logically. KnownAssignedXidsAdd() however expects XIDs in logical order, and calls TransactionIdFollowsOrEquals() to enforce that. If there are XIDs for which the two orderings disagree, an error is raised and the recovery fails/restarts. Hitting this issue is fairly easy - you just need two transactions, one started before the 4B limit (e.g. XID 4294967290), the other sometime after it (e.g. XID 1000). Logically (4294967290 <= 1000) but when compared using xidComparator we try to add them in the opposite order. Which makes KnownAssignedXidsAdd() fail with an error like this: ERROR: out-of-order XID insertion in KnownAssignedXids This only happens during replica startup, while processing RUNNING_XACTS records to build the snapshot. Once we reach STANDBY_SNAPSHOT_READY, we skip these records. So this does not affect already running replicas, but if you restart (or create) a replica while there are transactions with XIDs for which the two orderings disagree, you may hit this. Long-running transactions and frequent replica restarts increase the likelihood of hitting this issue. Once the replica gets into this state, it can't be started (even if the old transactions are terminated). Fixed by sorting the XIDs logically - this is fine because we're dealing with normal XIDs (because it's XIDs assigned to backends) and from the same wraparound epoch (otherwise the backends could not be running at the same time on the primary node). So there are no problems with the triangle inequality, which is why xidComparator compares raw values. Investigation and root cause analysis by Abhijit Menon-Sen. Patch by me. This issue is present in all releases since 9.4, however releases up to 9.6 are EOL already so backpatch to 10 only. Reviewed-by: Abhijit Menon-Sen Reviewed-by: Alvaro Herrera Backpatch-through: 10 Discussion: https://postgr.es/m/36b8a501-5d73-277c-4972-f58a4dce088a%40enterprisedb.com
2021-10-23Avoid race in RelationBuildDesc() affecting CREATE INDEX CONCURRENTLY.Noah Misch
CIC and REINDEX CONCURRENTLY assume backends see their catalog changes no later than each backend's next transaction start. That failed to hold when a backend absorbed a relevant invalidation in the middle of running RelationBuildDesc() on the CIC index. Queries that use the resulting index can silently fail to find rows. Fix this for future index builds by making RelationBuildDesc() loop until it finishes without accepting a relevant invalidation. It may be necessary to reindex to recover from past occurrences; REINDEX CONCURRENTLY suffices. Back-patch to 9.6 (all supported versions). Noah Misch and Andrey Borodin, reviewed (in earlier versions) by Andres Freund. Discussion: https://postgr.es/m/20210730022548.GA1940096@gust.leadboat.com
2021-10-01Fix Portal snapshot tracking to handle subtransactions properly.Tom Lane
Commit 84f5c2908 forgot to consider the possibility that EnsurePortalSnapshotExists could run inside a subtransaction with lifespan shorter than the Portal's. In that case, the new active snapshot would be popped at the end of the subtransaction, leaving a dangling pointer in the Portal, with mayhem ensuing. To fix, make sure the ActiveSnapshot stack entry is marked with the same subtransaction nesting level as the associated Portal. It's certainly safe to do so since we won't be here at all unless the stack is empty; hence we can't create an out-of-order stack. Let's also apply this logic in the case where PortalRunUtility sets portalSnapshot, just to be sure that path can't cause similar problems. It's slightly less clear that that path can't create an out-of-order stack, so add an assertion guarding it. Report and patch by Bertrand Drouvot (with kibitzing by me). Back-patch to v11, like the previous commit. Discussion: https://postgr.es/m/ff82b8c5-77f4-3fe7-6028-fcf3303e82dd@amazon.com
2021-05-21Restore the portal-level snapshot after procedure COMMIT/ROLLBACK.Tom Lane
COMMIT/ROLLBACK necessarily destroys all snapshots within the session. The original implementation of intra-procedure transactions just cavalierly did that, ignoring the fact that this left us executing in a rather different environment than normal. In particular, it turns out that handling of toasted datums depends rather critically on there being an outer ActiveSnapshot: otherwise, when SPI or the core executor pop whatever snapshot they used and return, it's unsafe to dereference any toasted datums that may appear in the query result. It's possible to demonstrate "no known snapshots" and "missing chunk number N for toast value" errors as a result of this oversight. Historically this outer snapshot has been held by the Portal code, and that seems like a good plan to preserve. So add infrastructure to pquery.c to allow re-establishing the Portal-owned snapshot if it's not there anymore, and add enough bookkeeping support that we can tell whether it is or not. We can't, however, just re-establish the Portal snapshot as part of COMMIT/ROLLBACK. As in normal transaction start, acquiring the first snapshot should wait until after SET and LOCK commands. Hence, teach spi.c about doing this at the right time. (Note that this patch doesn't fix the problem for any PLs that try to run intra-procedure transactions without using SPI to execute SQL commands.) This makes SPI's no_snapshots parameter rather a misnomer, so in HEAD, rename that to allow_nonatomic. replication/logical/worker.c also needs some fixes, because it wasn't careful to hold a snapshot open around AFTER trigger execution. That code doesn't use a Portal, which I suspect someday we're gonna have to fix. But for now, just rearrange the order of operations. This includes back-patching the recent addition of finish_estate() to centralize the cleanup logic there. This also back-patches commit 2ecfeda3e into v13, to improve the test coverage for worker.c (it was that test that exposed that worker.c's snapshot management is wrong). Per bug #15990 from Andreas Wicht. Back-patch to v11 where intra-procedure COMMIT was added. Discussion: https://postgr.es/m/15990-eee2ac466b11293d@postgresql.org
2021-05-10Prevent integer overflows in array subscripting calculations.Tom Lane
While we were (mostly) careful about ensuring that the dimensions of arrays aren't large enough to cause integer overflow, the lower bound values were generally not checked. This allows situations where lower_bound + dimension overflows an integer. It seems that that's harmless so far as array reading is concerned, except that array elements with subscripts notionally exceeding INT_MAX are inaccessible. However, it confuses various array-assignment logic, resulting in a potential for memory stomps. Fix by adding checks that array lower bounds aren't large enough to cause lower_bound + dimension to overflow. (Note: this results in disallowing cases where the last subscript position would be exactly INT_MAX. In principle we could probably allow that, but there's a lot of code that computes lower_bound + dimension and would need adjustment. It seems doubtful that it's worth the trouble/risk to allow it.) Somewhat independently of that, array_set_element() was careless about possible overflow when checking the subscript of a fixed-length array, creating a different route to memory stomps. Fix that too. Security: CVE-2021-32027
2021-02-10Preserve pg_attribute.attstattarget across REINDEX CONCURRENTLYMichael Paquier
For an index, attstattarget can be updated using ALTER INDEX SET STATISTICS. This data was lost on the new index after REINDEX CONCURRENTLY. The update of this field is done when the old and new indexes are swapped to make the fix back-patchable. Another approach we could look after in the long-term is to change index_create() to pass the wanted values of attstattarget when creating the new relation, but, as this would cause an ABI breakage this can be done only on HEAD. Reported-by: Ronan Dunklau Author: Michael Paquier Reviewed-by: Ronan Dunklau, Tomas Vondra Discussion: https://postgr.es/m/16628084.uLZWGnKmhe@laptop-ronand Backpatch-through: 12
2020-11-10Fix and simplify some usages of TimestampDifference().Tom Lane
Introduce TimestampDifferenceMilliseconds() to simplify callers that would rather have the difference in milliseconds, instead of the select()-oriented seconds-and-microseconds format. This gets rid of at least one integer division per call, and it eliminates some apparently-easy-to-mess-up arithmetic. Two of these call sites were in fact wrong: * pg_prewarm's autoprewarm_main() forgot to multiply the seconds by 1000, thus ending up with a delay 1000X shorter than intended. That doesn't quite make it a busy-wait, but close. * postgres_fdw's pgfdw_get_cleanup_result() thought it needed to compute microseconds not milliseconds, thus ending up with a delay 1000X longer than intended. Somebody along the way had noticed this problem but misdiagnosed the cause, and imposed an ad-hoc 60-second limit rather than fixing the units. This was relatively harmless in context, because we don't care that much about exactly how long this delay is; still, it's wrong. There are a few more callers of TimestampDifference() that don't have a direct need for seconds-and-microseconds, but can't use TimestampDifferenceMilliseconds() either because they do need microsecond precision or because they might possibly deal with intervals long enough to overflow 32-bit milliseconds. It might be worth inventing another API to improve that, but that seems outside the scope of this patch; so those callers are untouched here. Given the fact that we are fixing some bugs, and the likelihood that future patches might want to back-patch code that uses this new API, back-patch to all supported branches. Alexey Kondratov and Tom Lane Discussion: https://postgr.es/m/3b1c053a21c07c1ed5e00be3b2b855ef@postgrespro.ru
2020-06-05Use query collation, not column's collation, while examining statistics.Tom Lane
Commit 5e0928005 changed the planner so that, instead of blindly using DEFAULT_COLLATION_OID when invoking operators for selectivity estimation, it would use the collation of the column whose statistics we're considering. This was recognized as still being not quite the right thing, but it seemed like a good incremental improvement. However, shortly thereafter we introduced nondeterministic collations, and that creates cases where operators can fail if they're passed the wrong collation. We don't want planning to fail in cases where the query itself would work, so this means that we *must* use the query's collation when invoking operators for estimation purposes. The only real problem this creates is in ineq_histogram_selectivity, where the binary search might produce a garbage answer if we perform comparisons using a different collation than the column's histogram is ordered with. However, when the query's collation is significantly different from the column's default collation, the estimate we previously generated would be pretty irrelevant anyway; so it's not clear that this will result in noticeably worse estimates in practice. (A follow-on patch will improve this situation in HEAD, but it seems too invasive for back-patch.) The patch requires changing the signatures of mcv_selectivity and allied functions, which are exported and very possibly are used by extensions. In HEAD, I just did that, but an API/ABI break of this sort isn't acceptable in stable branches. Therefore, in v12 the patch introduces "mcv_selectivity_ext" and so on, with signatures matching HEAD, and makes the old functions into wrappers that assume DEFAULT_COLLATION_OID should be used. That does not match the prior behavior, but it should avoid risk of failure in most cases. (In practice, I think most extension datatypes aren't collation-aware, so the change probably doesn't matter to them.) Per report from James Lucas. Back-patch to v12 where the problem was introduced. Discussion: https://postgr.es/m/CAAFmbbOvfi=wMM=3qRsPunBSLb8BFREno2oOzSBS=mzfLPKABw@mail.gmail.com
2020-06-04Reject "23:59:60.nnn" in datetime input.Tom Lane
It's intentional that we don't allow values greater than 24 hours, while we do allow "24:00:00" as well as "23:59:60" as inputs. However, the range check was miscoded in such a way that it would accept "23:59:60.nnn" with a nonzero fraction. For time or timetz, the stored result would then be greater than "24:00:00" which would fail dump/reload, not to mention possibly confusing other operations. Fix by explicitly calculating the result and making sure it does not exceed 24 hours. (This calculation is redundant with what will happen later in tm2time or tm2timetz. Maybe someday somebody will find that annoying enough to justify refactoring to avoid the duplication; but that seems too invasive for a back-patched bug fix, and the cost is probably unmeasurable anyway.) Note that this change also rejects such input as the time portion of a timestamp(tz) value. Back-patch to v10. The bug is far older, but to change this pre-v10 we'd need to ensure that the logic behaves sanely with float timestamps, which is possibly nontrivial due to roundoff considerations. Doesn't really seem worth troubling with. Per report from Christoph Berg. Discussion: https://postgr.es/m/20200520125807.GB296739@msg.df7cb.de
2020-04-06Preserve clustered index after rewrites with ALTER TABLEMichael Paquier
A table rewritten by ALTER TABLE would lose tracking of an index usable for CLUSTER. This setting is tracked by pg_index.indisclustered and is controlled by ALTER TABLE, so some extra work was needed to restore it properly. Note that ALTER TABLE only marks the index that can be used for clustering, and does not do the actual operation. Author: Amit Langote, Justin Pryzby Reviewed-by: Ibrar Ahmed, Michael Paquier Discussion: https://postgr.es/m/20200202161718.GI13621@telsasoft.com Backpatch-through: 9.5
2020-03-24Re-implement the ereport() macro using __VA_ARGS__.Tom Lane
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
2020-03-22Revert "Skip WAL for new relfilenodes, under wal_level=minimal."Noah Misch
This reverts commit cb2fd7eac285b1b0a24eeb2b8ed4456b66c5a09f. Per numerous buildfarm members, it was incompatible with parallel query, and a test case assumed LP64. Back-patch to 9.5 (all supported versions). Discussion: https://postgr.es/m/20200321224920.GB1763544@rfd.leadboat.com
2020-03-21Skip WAL for new relfilenodes, under wal_level=minimal.Noah Misch
Until now, only selected bulk operations (e.g. COPY) did this. If a given relfilenode received both a WAL-skipping COPY and a WAL-logged operation (e.g. INSERT), recovery could lose tuples from the COPY. See src/backend/access/transam/README section "Skipping WAL for New RelFileNode" for the new coding rules. Maintainers of table access methods should examine that section. To maintain data durability, just before commit, we choose between an fsync of the relfilenode and copying its contents to WAL. A new GUC, wal_skip_threshold, guides that choice. If this change slows a workload that creates small, permanent relfilenodes under wal_level=minimal, try adjusting wal_skip_threshold. Users setting a timeout on COMMIT may need to adjust that timeout, and log_min_duration_statement analysis will reflect time consumption moving to COMMIT from commands like COPY. Internally, this requires a reliable determination of whether RollbackAndReleaseCurrentSubTransaction() would unlink a relation's current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the specification of rd_createSubid such that the field is zero when a new rel has an old rd_node. Make relcache.c retain entries for certain dropped relations until end of transaction. Back-patch to 9.5 (all supported versions). This introduces a new WAL record type, XLOG_GIST_ASSIGN_LSN, without bumping XLOG_PAGE_MAGIC. As always, update standby systems before master systems. This changes sizeof(RelationData) and sizeof(IndexStmt), breaking binary compatibility for affected extensions. (The most recent commit to affect the same class of extensions was 089e4d405d0f3b94c74a2c6a54357a84a681754b.) Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert Haas. Heikki Linnakangas and Michael Paquier implemented earlier designs that materially clarified the problem. Reviewed, in earlier designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane, Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout. Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
2020-03-21Fix cosmetic blemishes involving rd_createSubid.Noah Misch
Remove an obsolete comment from AtEOXact_cleanup(). Restore formatting of a comment in struct RelationData, mangled by the pgindent run in commit 9af4159fce6654aa0e081b00d02bca40b978745c. Back-patch to 9.5 (all supported versions), because another fix stacks on this.
2020-03-13Preserve replica identity index across ALTER TABLE rewritePeter Eisentraut
If an index was explicitly set as replica identity index, this setting was lost when a table was rewritten by ALTER TABLE. Because this setting is part of pg_index but actually controlled by ALTER TABLE (not part of CREATE INDEX, say), we have to do some extra work to restore it. Based-on-patch-by: Quan Zongliang <quanzongliang@gmail.com> Reviewed-by: Euler Taveira <euler.taveira@2ndquadrant.com> Discussion: https://www.postgresql.org/message-id/flat/c70fcab2-4866-0d9f-1d01-e75e189db342@gmail.com
2020-03-10Prevent reindex of invalid indexes on TOAST tablesMichael Paquier
Such indexes can only be duplicated leftovers of a previously failed REINDEX CONCURRENTLY command, and a valid equivalent is guaranteed to exist. As toast indexes can only be dropped if invalid, reindexing these would lead to useless duplicated indexes that can't be dropped anymore, except if the parent relation is dropped. Thanks to Justin Pryzby for reminding that this problem was reported long ago during the review of the original patch of REINDEX CONCURRENTLY, but the issue was never addressed. Reported-by: Sergei Kornilov, Justin Pryzby Author: Julien Rouhaud Reviewed-by: Michael Paquier Discussion: https://postgr.es/m/36712441546604286%40sas1-890ba5c2334a.qloud-c.yandex.net Discussion: https://postgr.es/m/20200216190835.GA21832@telsasoft.com Backpatch-through: 12
2020-02-13Avoid a performance regression in float overflow/underflow detection.Tom Lane
Commit 6bf0bc842 replaced float.c's CHECKFLOATVAL() macro with static inline subroutines, but that wasn't too well thought out. In the original coding, the unlikely condition (isinf(result) or result == 0) was checked first, and the inf_is_valid or zero_is_valid condition only afterwards. The inline-subroutine coding caused that to be swapped around, which is pretty horrid for performance because (a) in common cases the is_valid condition is twice as expensive to evaluate (e.g., requiring two isinf() calls not one) and (b) in common cases the is_valid condition is false, requiring us to perform the unlikely-condition check anyway. Net result is that one isinf() call becomes two or three, resulting in visible performance loss as reported by Keisuke Kuroda. The original fix proposal was to revert the replacement of the macro, but on second thought, that macro was just a bad idea from the beginning: if anything it's a net negative for readability of the code. So instead, let's just open-code all the overflow/underflow tests, being careful to test the unlikely condition first (and mark it unlikely() to help the compiler get the point). Also, rather than having N copies of the actual ereport() calls, collapse those into out-of-line error subroutines to save some code space. This does mean that the error file/line numbers won't be very helpful for figuring out where the issue really is --- but we'd already burned that bridge by putting the ereports into static inlines. In HEAD, check_float[48]_val() are gone altogether. In v12, leave them present in float.h but unused in the core code, just in case some extension is depending on them. Emre Hasegeli, with some kibitzing from me and Andres Freund Discussion: https://postgr.es/m/CANDwggLe1Gc1OrRqvPfGE=kM9K0FSfia0hbeFCEmwabhLz95AA@mail.gmail.com
2020-01-31Fix CheckAttributeType's handling of collations for ranges.Tom Lane
Commit fc7695891 changed CheckAttributeType to recurse into ranges, but made it pass down the wrong collation (always InvalidOid, since ranges as such have no collation). This would result in guaranteed failure when considering a range type whose subtype is collatable. Embarrassingly, we lack any regression tests that would expose such a problem (but fortunately, somebody noticed before we shipped this bug in any release). Fix it to pass down the range's subtype collation property instead, and add some regression test cases to exercise collatable-subtype ranges a bit more. Back-patch to all supported branches, as the previous patch was. Report and patch by Julien Rouhaud, test cases tweaked by me Discussion: https://postgr.es/m/CAOBaU_aBWqNweiGUFX0guzBKkcfJ8mnnyyGC_KBQmO12Mj5f_A@mail.gmail.com
2019-12-01Fix misbehavior with expression indexes on ON COMMIT DELETE ROWS tables.Tom Lane
We implement ON COMMIT DELETE ROWS by truncating tables marked that way, which requires also truncating/rebuilding their indexes. But RelationTruncateIndexes asks the relcache for up-to-date copies of any index expressions, which may cause execution of eval_const_expressions on them, which can result in actual execution of subexpressions. This is a bad thing to have happening during ON COMMIT. Manuel Rigger reported that use of a SQL function resulted in crashes due to expectations that ActiveSnapshot would be set, which it isn't. The most obvious fix perhaps would be to push a snapshot during PreCommit_on_commit_actions, but I think that would just open the door to more problems: CommitTransaction explicitly expects that no user-defined code can be running at this point. Fortunately, since we know that no tuples exist to be indexed, there seems no need to use the real index expressions or predicates during RelationTruncateIndexes. We can set up dummy index expressions instead (we do need something that will expose the right data type, as there are places that build index tupdescs based on this), and just ignore predicates and exclusion constraints. In a green field it'd likely be better to reimplement ON COMMIT DELETE ROWS using the same "init fork" infrastructure used for unlogged relations. That seems impractical without catalog changes though, and even without that it'd be too big a change to back-patch. So for now do it like this. Per private report from Manuel Rigger. This has been broken forever, so back-patch to all supported branches.
2019-09-22Fix failure to zero-pad the result of bitshiftright().Tom Lane
If the bitstring length is not a multiple of 8, we'd shift the rightmost bits into the pad space, which must be zeroes --- bit_cmp, for one, depends on that. This'd lead to the result failing to compare equal to what it should compare equal to, as reported in bug #16013 from Daryl Waycott. This is, if memory serves, not the first such bug in the bitstring functions. In hopes of making it the last one, do a bit more work than minimally necessary to fix the bug: * Add assertion checks to bit_out() and varbit_out() to complain if they are given incorrectly-padded input. This will improve the odds that manual testing of any new patch finds problems. * Encapsulate the padding-related logic in macros to make it easier to use. Also, remove unnecessary padding logic from bit_or() and bitxor(). Somebody had already noted that we need not re-pad the result of bit_and() since the inputs are required to be the same length, but failed to extrapolate that to the other two. Also, move a comment block that once was near the head of varbit.c (but people kept putting other stuff in front of it), to put it in the header block. Note for the release notes: if anyone has inconsistent data as a result of saving the output of bitshiftright() in a table, it's possible to fix it with something like UPDATE mytab SET bitcol = ~(~bitcol) WHERE bitcol != ~(~bitcol); This has been broken since day one, so back-patch to all supported branches. Discussion: https://postgr.es/m/16013-c2765b6996aacae9@postgresql.org
2019-09-17Fix bogus handling of XQuery regex option flags.Tom Lane
The SQL spec defers to XQuery to define what the option flags are for LIKE_REGEX patterns. XQuery says that: * 's' allows the dot character to match newlines, which by default it will not; * 'm' allows ^ and $ to match at newlines, not only at the start/end of the whole string. Thus, these are *not* inverses as they are for the similarly-named POSIX options, and neither one corresponds to the POSIX 'n' option. Fortunately, Spencer's library does expose these two behaviors as separately twiddlable flags, so we just have to fix the mapping from JSP flag bits to REG flag bits. I also chose to rename the symbol for 's' to DOTALL, to make it clearer that it's not the inverse of MLINE. Also, XQuery says that if the 'q' flag "is used together with the m, s, or x flag, that flag has no effect". I read this as saying that 'q' overrides the other flags; whoever wrote our code seems to have read it backwards. Lastly, while XQuery's 'x' flag is related to what Spencer's code does for REG_EXPANDED, it's not the same or a subset. It seems best to treat XQuery's 'x' as unimplemented for now. Maybe later we can expand our regex code to offer 'x'-style parsing as a separate option. While at it, refactor the jsonpath code so that (a) there's only one copy of the flag transformation logic not two, and (b) the processing of flags is independent of the order in which the flags are written. We need some documentation updates to go with this, but I'll tackle that separately. Back-patch to v12 where this code originated. Discussion: https://postgr.es/m/CAPpHfdvDci4iqNF9fhRkTqhe-5_8HmzeLt56drH%2B_Rv2rNRqfg@mail.gmail.com Reference: https://www.w3.org/TR/2017/REC-xpath-functions-31-20170321/#flags
2019-08-28Avoid catalog lookups in RelationAllowsEarlyPruning().Thomas Munro
RelationAllowsEarlyPruning() performed a catalog scan, but is used in two contexts where that was a bad idea: 1. In heap_page_prune_opt(), which runs very frequently in some large scans. This caused major performance problems in a field report that was easy to reproduce. 2. In TestForOldSnapshot(), which runs while we hold a buffer content lock. It's not clear if this was guaranteed to be free of buffer deadlock risk. The check was introduced in commit 2cc41acd8 and defended against a real problem: 9.6's hash indexes have no page LSN and so we can't allow early pruning (ie the snapshot-too-old feature). We can remove the check from all later releases though: hash indexes are now logged, and there is no way to create UNLOGGED indexes on regular logged tables. If a future release allows such a combination, it might need to put a similar check in place, but it'll need some more thought. Back-patch to 10. Author: Thomas Munro Reviewed-by: Tom Lane, who spotted the second problem Discussion: https://postgr.es/m/CA%2BhUKGKT8oTkp5jw_U4p0S-7UG9zsvtw_M47Y285bER6a2gD%2Bg%40mail.gmail.com Discussion: https://postgr.es/m/CAA4eK1%2BWy%2BN4eE5zPm765h68LrkWc3Biu_8rzzi%2BOYX4j%2BiHRw%40mail.gmail.com
2019-08-04Revert "Add log_statement_sample_rate parameter"Tomas Vondra
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
2019-07-31Remove superfluous newlines in function prototypes.Andres Freund
These were introduced by pgindent due to fixe to broken indentation (c.f. 8255c7a5eeba8). Previously the mis-indentation of function prototypes was creatively used to reduce indentation in a few places. As that formatting only exists in master and REL_12_STABLE, it seems better to fix it in both, rather than having some odd indentation in v12 that somebody might copy for future patches or such. Author: Andres Freund Discussion: https://postgr.es/m/20190728013754.jwcbe5nfyt3533vx@alap3.anarazel.de Backpatch: 12-
2019-07-30Allow table AM's to use rd_amcache, too.Heikki Linnakangas
The rd_amcache allows an index AM to cache arbitrary information in a relcache entry. This commit moves the cleanup of rd_amcache so that it can also be used by table AMs. Nothing takes advantage of that yet, but I'm sure it'll come handy for anyone writing new table AMs. Backpatch to v12, where table AM interface was introduced. Reviewed-by: Julien Rouhaud
2019-07-24Use full 64-bit XID for checking if a deleted GiST page is old enough.Heikki Linnakangas
Otherwise, after a deleted page gets even older, it becomes unrecyclable again. B-tree has the same problem, and has had since time immemorial, but let's at least fix this in GiST, where this is new. Backpatch to v12, where GiST page deletion was introduced. Reviewed-by: Andrey Borodin Discussion: https://www.postgresql.org/message-id/835A15A5-F1B4-4446-A711-BF48357EB602%40yandex-team.ru
2019-07-01Fix many typos and inconsistenciesMichael Paquier
Author: Alexander Lakhin Discussion: https://postgr.es/m/af27d1b3-a128-9d62-46e0-88f424397f44@gmail.com
2019-06-30Don't read fields of a misaligned ExpandedObjectHeader or AnyArrayType.Noah Misch
UBSan complains about this. Instead, cast to a suitable type requiring only 4-byte alignment. DatumGetAnyArrayP() already assumes one can cast between AnyArrayType and ArrayType, so this doesn't introduce a new assumption. Back-patch to 9.5, where AnyArrayType was introduced. Reviewed by Tom Lane. Discussion: https://postgr.es/m/20190629210334.GA1244217@rfd.leadboat.com
2019-06-30Don't call data type input functions in GUC check hooksPeter Eisentraut
Instead of calling pg_lsn_in() in check_recovery_target_lsn and timestamptz_in() in check_recovery_target_time, reorganize the respective code so that we don't raise any errors in the check hooks. The previous code tried to use PG_TRY/PG_CATCH to handle errors in a way that is not safe, so now the code contains no ereport() calls and can operate safely within the GUC error handling system. Moreover, since the interpretation of the recovery_target_time string may depend on the time zone, we cannot do the final processing of that string until all the GUC processing is done. Instead, check_recovery_target_time() now does some parsing for syntax checking, but the actual conversion to a timestamptz value is done later in the recovery code that uses it. Reported-by: Andres Freund <andres@anarazel.de> Reviewed-by: Michael Paquier <michael@paquier.xyz> Discussion: https://www.postgresql.org/message-id/flat/20190611061115.njjwkagvxp4qujhp%40alap3.anarazel.de
2019-06-30Remove explicit error handling for obsolete date/time valuesPeter Eisentraut
The date/time values 'current', 'invalid', and 'undefined' were removed a long time ago, but the code still contains explicit error handling for the transition. To simplify the code and avoid having to handle these values everywhere, just remove the recognition of these tokens altogether now. Reviewed-by: Michael Paquier <michael@paquier.xyz>
2019-06-19Support 'q' flag in jsonpath 'like_regex' predicateAlexander Korotkov
SQL/JSON standard defines that jsonpath 'like_regex' predicate should support the same set of flags as XQuery/XPath. It appears that implementation of 'q' flag was missed. This commit fixes that. Discussion: https://postgr.es/m/CAPpHfdtyfPsxLYiTjp5Ov8T5xGsB5t3CwE5%2B3PS%3DLLwA%2BxTJog%40mail.gmail.com Author: Nikita Glukhov, Alexander Korotkov
2019-06-17Fix more typos and inconsistencies in the treeMichael Paquier
Author: Alexander Lakhin Discussion: https://postgr.es/m/0a5419ea-1452-a4e6-72ff-545b1a5a8076@gmail.com
2019-06-16Rework the pg_statistic_ext catalogTomas Vondra
Since extended statistic got introduced in PostgreSQL 10, there was a single catalog pg_statistic_ext storing both the definitions and built statistic. That's however problematic when a user is supposed to have access only to the definitions, but not to user data. Consider for example pg_dump on a database with RLS enabled - if the pg_statistic_ext catalog respects RLS (which it should, if it contains user data), pg_dump would not see any records and the result would not define any extended statistics. That would be a surprising behavior. Until now this was not a pressing issue, because the existing types of extended statistic (functional dependencies and ndistinct coefficients) do not include any user data directly. This changed with introduction of MCV lists, which do include most common combinations of values. The easiest way to fix this is to split the pg_statistic_ext catalog into two - one for definitions, one for the built statistic values. The new catalog is called pg_statistic_ext_data, and we're maintaining a 1:1 relationship with the old catalog - either there are matching records in both catalogs, or neither of them. Bumped CATVERSION due to changing system catalog definitions. Author: Dean Rasheed, with improvements by me Reviewed-by: Dean Rasheed, John Naylor Discussion: https://postgr.es/m/CAEZATCUhT9rt7Ui%3DVdx4N%3D%3DVV5XOK5dsXfnGgVOz_JhAicB%3DZA%40mail.gmail.com
2019-06-13Fix double-word typosAlvaro Herrera
Discussion: https://postgr.es/m/20190612184527.GA24266@alvherre.pgsql Reviewed-by: Michaƫl Paquier
2019-05-26Fix typos.Amit Kapila
Reported-by: Alexander Lakhin Author: Alexander Lakhin Reviewed-by: Amit Kapila and Tom Lane Discussion: https://postgr.es/m/7208de98-add8-8537-91c0-f8b089e2928c@gmail.com
2019-05-22Phase 2 pgindent run for v12.Tom Lane
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
2019-05-22Initial pgindent run for v12.Tom Lane
This is still using the 2.0 version of pg_bsd_indent. I thought it would be good to commit this separately, so as to document the differences between 2.0 and 2.1 behavior. Discussion: https://postgr.es/m/16296.1558103386@sss.pgh.pa.us
2019-05-19Fix and improve SnapshotType comments.Andres Freund
The comment for SNAPSHOT_SELF was unfortunately explaining SNAPSHOT_DIRTY, as reported by Sergei. Also expand a few comments, and include a few more comments from heapam_visibility.c, so they're in an AM independent place. Reported-By: Sergei Kornilov Author: Andres Freund Discussion: https://postgr.es/m/9152241558192351@sas1-d856b3d759c7.qloud-c.yandex.net
2019-05-03Remove RelationSetIndexList().Tom Lane
In the wake of commit f912d7dec, RelationSetIndexList isn't used any more. It was always a horrid wart, so getting rid of it is very nice. We can also convert rd_indexvalid back to a plain boolean. Discussion: https://postgr.es/m/28926.1556664156@sss.pgh.pa.us
2019-04-13Prevent memory leaks associated with relcache rd_partcheck structures.Tom Lane
The original coding of generate_partition_qual() just copied the list of predicate expressions into the global CacheMemoryContext, making it effectively impossible to clean up when the owning relcache entry is destroyed --- the relevant code in RelationDestroyRelation() only managed to free the topmost List header :-(. This resulted in a session-lifespan memory leak whenever a table partition's relcache entry is rebuilt. Fortunately, that's not normally a large data structure, and rebuilds shouldn't occur all that often in production situations; but this is still a bug worth fixing back to v10 where the code was introduced. To fix, put the cached expression tree into its own small memory context, as we do with other complicated substructures of relcache entries. Also, deal more honestly with the case that a partition has an empty partcheck list; while that probably isn't a case that's very interesting for production use, it's legal. In passing, clarify comments about how partitioning-related relcache data structures are managed, and add some Asserts that we're not leaking old copies when we overwrite these data fields. Amit Langote and Tom Lane Discussion: https://postgr.es/m/7961.1552498252@sss.pgh.pa.us
2019-04-08Add vacuum_truncate reloption.Fujii Masao
vacuum_truncate controls whether vacuum tries to truncate off any empty pages at the end of the table. Previously vacuum always tried to do the truncation. However, the truncation could cause some problems; for example, ACCESS EXCLUSIVE lock needs to be taken on the table during the truncation and can cause the query cancellation on the standby even if hot_standby_feedback is true. Setting this reloption to false can be helpful to avoid such problems. Author: Tsunakawa Takayuki Reviewed-By: Julien Rouhaud, Masahiko Sawada, Michael Paquier, Kirk Jamison and Fujii Masao Discussion: https://postgr.es/m/CAHGQGwE5UqFqSq1=kV3QtTUtXphTdyHA-8rAj4A=Y+e4kyp3BQ@mail.gmail.com