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* Fix strange behavior (and possible crashes) in full text phrase search.Tom Lane2016-12-21
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | In an attempt to simplify the tsquery matching engine, the original phrase search patch invented rewrite rules that would rearrange a tsquery so that no AND/OR/NOT operator appeared below a PHRASE operator. But this approach had numerous problems. The rearrangement step was missed by ts_rewrite (and perhaps other places), allowing tsqueries to be created that would cause Assert failures or perhaps crashes at execution, as reported by Andreas Seltenreich. The rewrite rules effectively defined semantics for operators underneath PHRASE that were buggy, or at least unintuitive. And because rewriting was done in tsqueryin() rather than at execution, the rearrangement was user-visible, which is not very desirable --- for example, it might cause unexpected matches or failures to match in ts_rewrite. As a somewhat independent problem, the behavior of nested PHRASE operators was only sane for left-deep trees; queries like "x <-> (y <-> z)" did not behave intuitively at all. To fix, get rid of the rewrite logic altogether, and instead teach the tsquery execution engine to manage AND/OR/NOT below a PHRASE operator by explicitly computing the match location(s) and match widths for these operators. This requires introducing some additional fields into the publicly visible ExecPhraseData struct; but since there's no way for third-party code to pass such a struct to TS_phrase_execute, it shouldn't create an ABI problem as long as we don't move the offsets of the existing fields. Another related problem was that index searches supposed that "!x <-> y" could be lossily approximated as "!x & y", which isn't correct because the latter will reject, say, "x q y" which the query itself accepts. This required some tweaking in TS_execute_ternary along with the main tsquery engine. Back-patch to 9.6 where phrase operators were introduced. While this could be argued to change behavior more than we'd like in a stable branch, we have to do something about the crash hazards and index-vs-seqscan inconsistency, and it doesn't seem desirable to let the unintuitive behaviors induced by the rewriting implementation stand as precedent. Discussion: https://postgr.es/m/28215.1481999808@sss.pgh.pa.us Discussion: https://postgr.es/m/26706.1482087250@sss.pgh.pa.us
* Fix corner-case bug in WaitEventSetWaitBlock on Windows.Robert Haas2016-12-21
| | | | | | | | | | | | | | | | | If we do not reset the FD_READ event, WaitForMultipleObjects won't return it again again unless we've meanwhile read from the socket, which is generally true but not guaranteed. WaitEventSetWaitBlock itself may fail to return the event to the caller if the latch is also set, and even if we changed that, the caller isn't obliged to handle all returned events at once. On non-Windows systems, the socket-read event is purely level-triggered, so this issue does not exist. To fix, make Windows reset the event when needed. This bug was introduced by 98a64d0bd713cb89e61bef6432befc4b7b5da59e, and causes hangs when trying to use the pldebugger extension. Patch by Amit Kapial. Reported and tested by Ashutosh Sharma, who also provided some analysis. Further analysis by Michael Paquier.
* Improve documentation around TS_execute().Tom Lane2016-12-16
| | | | | | | | | | I got frustrated by the lack of commentary in this area, so here is some reverse-engineered documentation, along with minor stylistic cleanup. No code changes more significant than removal of unused variables. Back-patch to 9.6, not because that's useful in itself, but because we have some bugs to fix in phrase search and this would cause merge failures if it's only in HEAD.
* Revert "Permit dump/reload of not-too-large >1GB tuples"Alvaro Herrera2016-12-06
| | | | | | This reverts commit 4e01ecae98275298c680c92fdba62daf603dc98e. Per Tom Lane, changing the definition of StringInfoData amounts to an ABI break, which is unacceptable in back branches.
* Permit dump/reload of not-too-large >1GB tuplesAlvaro Herrera2016-12-02
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Our documentation states that our maximum field size is 1 GB, and that our maximum row size of 1.6 TB. However, while this might be attainable in theory with enough contortions, it is not workable in practice; for starters, pg_dump fails to dump tables containing rows larger than 1 GB, even if individual columns are well below the limit; and even if one does manage to manufacture a dump file containing a row that large, the server refuses to load it anyway. This commit enables dumping and reloading of such tuples, provided two conditions are met: 1. no single column is larger than 1 GB (in output size -- for bytea this includes the formatting overhead) 2. the whole row is not larger than 2 GB There are three related changes to enable this: a. StringInfo's API now has two additional functions that allow creating a string that grows beyond the typical 1GB limit (and "long" string). ABI compatibility is maintained. We still limit these strings to 2 GB, though, for reasons explained below. b. COPY now uses long StringInfos, so that pg_dump doesn't choke trying to emit rows longer than 1GB. c. heap_form_tuple now uses the MCXT_ALLOW_HUGE flag in its allocation for the input tuple, which means that large tuples are accepted on input. Note that at this point we do not apply any further limit to the input tuple size. The main reason to limit to 2 GB is that the FE/BE protocol uses 32 bit length words to describe each row; and because the documentation is ambiguous on its signedness and libpq does consider it signed, we cannot use the highest-order bit. Additionally, the StringInfo API uses "int" (which is 4 bytes wide in most platforms) in many places, so we'd need to change that API too in order to improve, which has lots of fallout. Backpatch to 9.5, which is the oldest that has MemoryContextAllocExtended, a necessary piece of infrastructure. We could apply to 9.4 with very minimal additional effort, but any further than that would require backpatching "huge" allocations too. This is the largest set of changes we could find that can be back-patched without breaking compatibility with existing systems. Fixing a bigger set of problems (for example, dumping tuples bigger than 2GB, or dumping fields bigger than 1GB) would require changing the FE/BE protocol and/or changing the StringInfo API in an ABI-incompatible way, neither of which would be back-patchable. Authors: Daniel Vérité, Álvaro Herrera Reviewed by: Tomas Vondra Discussion: https://postgr.es/m/20160229183023.GA286012@alvherre.pgsql
* Bring some clarity to the defaults for the xxx_flush_after parameters.Tom Lane2016-11-25
| | | | | | | | | | | | | | | | | | | | | | | | | | Instead of confusingly stating platform-dependent defaults for these parameters in the comments in postgresql.conf.sample (with the main entry being a lie on Linux), teach initdb to install the correct platform-dependent value in postgresql.conf, similarly to the way we handle other platform-dependent defaults. This won't do anything for existing 9.6 installations, but since it's effectively only a documentation improvement, that seems OK. Since this requires initdb to have access to the default values, move the #define's for those to pg_config_manual.h; the original placement in bufmgr.h is unworkable because that file can't be included by frontend programs. Adjust the default value for wal_writer_flush_after so that it is 1MB regardless of XLOG_BLCKSZ, conforming to what is stated in both the SGML docs and postgresql.conf. (We could alternatively make it scale with XLOG_BLCKSZ, but I'm not sure I see the point.) Copy-edit related SGML documentation. Fabien Coelho and Tom Lane, per a gripe from Tomas Vondra. Discussion: <30ebc6e3-8358-09cf-44a8-578252938424@2ndquadrant.com>
* Account for catalog snapshot in PGXACT->xmin updates.Tom Lane2016-11-15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The CatalogSnapshot was not plugged into SnapshotResetXmin()'s accounting for whether MyPgXact->xmin could be cleared or advanced. In normal transactions this was masked by the fact that the transaction snapshot would be older, but during backend startup and certain utility commands it was possible to re-use the CatalogSnapshot after MyPgXact->xmin had been cleared, meaning that recently-deleted rows could be pruned even though this snapshot could still see them, causing unexpected catalog lookup failures. This effect appears to be the explanation for a recent failure on buildfarm member piculet. To fix, add the CatalogSnapshot to the RegisteredSnapshots heap whenever it is valid. In the previous logic, it was possible for the CatalogSnapshot to remain valid across waits for client input, but with this change that would mean it delays advance of global xmin in cases where it did not before. To avoid possibly causing new table-bloat problems with clients that sit idle for long intervals, add code to invalidate the CatalogSnapshot before waiting for client input. (When the backend is busy, it's unlikely that the CatalogSnapshot would be the oldest snap for very long, so we don't worry about forcing early invalidation of it otherwise.) In passing, remove the CatalogSnapshotStale flag in favor of using "CatalogSnapshot != NULL" to represent validity, as we do for the other special snapshots in snapmgr.c. And improve some obsolete comments. No regression test because I don't know a deterministic way to cause this failure. But the stress test shown in the original discussion provokes "cache lookup failed for relation 1255" within a few dozen seconds for me. Back-patch to 9.4 where MVCC catalog scans were introduced. (Note: it's quite easy to produce similar failures with the same test case in branches before 9.4. But MVCC catalog scans were supposed to fix that.) Discussion: <16447.1478818294@sss.pgh.pa.us>
* Re-allow user_catalog_table option for materialized views.Tom Lane2016-11-10
| | | | | | | | | | The reloptions stuff allows this option to be set on a matview. While it's questionable whether that is useful or was really intended, it does work, and we shouldn't change that in minor releases. Commit e3e66d8a9 disabled the option since I didn't realize that it was possible for it to be set on a matview. Tweak the test to re-allow it. Discussion: <19749.1478711862@sss.pgh.pa.us>
* Band-aid fix for incorrect use of view options as StdRdOptions.Tom Lane2016-11-07
| | | | | | | | | | We really ought to make StdRdOptions and the other decoded forms of reloptions self-identifying, but for the moment, assume that only plain relations could possibly be user_catalog_tables. Fixes problem with bogus "ON CONFLICT is not supported on table ... used as a catalog table" error when target is a view with cascade option. Discussion: <26681.1477940227@sss.pgh.pa.us>
* Remove duplicate macro definition.Tom Lane2016-11-05
| | | | | | | Seems to be a copy-and-pasteo. Odd that we heard no reports of compiler warnings about it. Thomas Munro
* Fix typos in comments.Heikki Linnakangas2016-10-26
| | | | Vinayak Pokale
* Stamp 9.6.1.REL9_6_1Tom Lane2016-10-24
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* Revert addition of PGDLLEXPORT in PG_FUNCTION_INFO_V1 macro.Tom Lane2016-10-12
| | | | | | | | | | | | | | | | | | This turns out not to be as harmless as I thought: MSVC will complain if it sees an "extern" declaration without PGDLLEXPORT and then one with. (Seems fairly silly, given that this can be changed after the fact by the linker, but there you have it.) Therefore, contrib modules that have extern's for V1 functions in header files are falling over in the buildfarm, since none of those externs are marked PGDLLEXPORT. We might or might not conclude that we're willing to plaster those declarations with PGDLLEXPORT in HEAD, but in any case there's no way we're going to ship this change in the back branches. Third-party authors would not thank us for breaking their code in a minor release. Hence, revert the addition of PGDLLEXPORT (but let's keep the extra info in the comment). If we do the other changes we can revert this commit in HEAD. Per buildfarm.
* Provide DLLEXPORT markers for C functions via PG_FUNCTION_INFO_V1 macro.Tom Lane2016-10-12
| | | | | | | | | | | | | | | | This isn't really necessary for our own code, because we use a .DEF file in MSVC builds (see gendef.pl), or --export-all-symbols in MinGW and Cygwin builds, to ensure that all global symbols in loadable modules will be exported on Windows. However, third-party authors might use different build processes that need this marker, and it's harmless enough for our own builds. To some extent, this is an oversight in commit e7128e8db, so back-patch to 9.4 where that was added. Laurenz Albe Discussion: <A737B7A37273E048B164557ADEF4A58B539300BD@ntex2010a.host.magwien.gv.at>
* Fix copy-pasto in comment.Heikki Linnakangas2016-10-12
| | | | Amit Langote
* Fix fallback implementation of pg_atomic_write_u32().Andres Freund2016-10-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I somehow had assumed that in the spinlock (in turn possibly using semaphores) based fallback atomics implementation 32 bit writes could be done without a lock. As far as the write goes that's correct, since postgres supports only platforms with single-copy atomicity for aligned 32bit writes. But writing without holding the spinlock breaks read-modify-write operations like pg_atomic_compare_exchange_u32(), since they'll potentially "miss" a concurrent write, which can't happen in actual hardware implementations. In 9.6+ when using the fallback atomics implementation this could lead to buffer header locks not being properly marked as released, and potentially some related state corruption. I don't see a related danger in 9.5 (earliest release with the API), because pg_atomic_write_u32() wasn't used in a concurrent manner there. The state variable of local buffers, before this change, were manipulated using pg_atomic_write_u32(), to avoid unnecessary synchronization overhead. As that'd not be the case anymore, introduce and use pg_atomic_unlocked_write_u32(), which does not correctly interact with RMW operations. This bug only caused issues when postgres is compiled on platforms without atomics support (i.e. no common new platform), or when compiled with --disable-atomics, which explains why this wasn't noticed in testing. Reported-By: Tom Lane Discussion: <14947.1475690465@sss.pgh.pa.us> Backpatch: 9.5-, where the atomic operations API was introduced.
* Show a sensible value in pg_settings.unit for GUC_UNIT_XSEGS variables.Tom Lane2016-10-03
| | | | | | | | | | | | | | | | Commit 88e982302 invented GUC_UNIT_XSEGS for min_wal_size and max_wal_size, but neglected to make it display sensibly in pg_settings.unit (by adding a case to the switch in GetConfigOptionByNum). Fix that, and adjust said switch to throw a run-time error the next time somebody forgets. In passing, avoid using a static buffer for the output string --- the rest of this function pstrdup's from a local buffer, and I see no very good reason why the units code should do it differently and less safely. Per report from Otar Shavadze. Back-patch to 9.5 where the new unit type was added. Report: <CAG-jOyA=iNFhN+yB4vfvqh688B7Tr5SArbYcFUAjZi=0Exp-Lg@mail.gmail.com>
* Stamp 9.6.0.REL9_6_0Tom Lane2016-09-26
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* Avoid using PostmasterRandom() for DSM control segment ID.Tom Lane2016-09-23
| | | | | | | | | | | | | | | Commits 470d886c3 et al intended to fix the problem that the postmaster selected the same "random" DSM control segment ID on every start. But using PostmasterRandom() for that destroys the intended property that the delay between random_start_time and random_stop_time will be unpredictable. (Said delay is probably already more predictable than we could wish, but that doesn't mean that reducing it by a couple orders of magnitude is OK.) Revert the previous patch and add a comment warning against misuse of PostmasterRandom. Fix the original problem by calling srandom() early in PostmasterMain, using a low-security seed that will later be overwritten by PostmasterRandom. Discussion: <20789.1474390434@sss.pgh.pa.us>
* Use PostmasterRandom(), not random(), for DSM control segment ID.Robert Haas2016-09-20
| | | | | Otherwise, every startup gets the same "random" value, which is definitely not what was intended.
* Fix outdated comments, GIST search queue is not an RBTree anymore.Heikki Linnakangas2016-09-20
| | | | | | The GiST search queue is implemented as a pairing heap rather than as Red-Black Tree, since 9.5 (commit e7032610). I neglected these comments in that commit.
* Fix building with LibreSSL.Heikki Linnakangas2016-09-15
| | | | | | | | | | | | | | | | LibreSSL defines OPENSSL_VERSION_NUMBER to claim that it is version 2.0.0, but it doesn't have the functions added in OpenSSL 1.1.0. Add autoconf checks for the individual functions we need, and stop relying on OPENSSL_VERSION_NUMBER. Backport to 9.5 and 9.6, like the patch that broke this. In the back-branches, there are still a few OPENSSL_VERSION_NUMBER checks left, to check for OpenSSL 0.9.8 or 0.9.7. I left them as they were - LibreSSL has all those functions, so they work as intended. Per buildfarm member curculio. Discussion: <2442.1473957669@sss.pgh.pa.us>
* Improve unreachability recognition in elog() macro.Tom Lane2016-09-10
| | | | | | | | | | | | | | Some experimentation with an older version of gcc showed that it is able to determine whether "if (elevel_ >= ERROR)" is compile-time constant if elevel_ is declared "const", but otherwise not so much. We had accounted for that in ereport() but were too miserly with braces to make it so in elog(). I don't know how many currently-interesting compilers have the same quirk, but in case it will save some code space, let's make sure that elog() is on the same footing as ereport() for this purpose. Back-patch to 9.3 where we introduced pg_unreachable() calls into elog/ereport.
* Update comments to reflect code rearrangement.Robert Haas2016-08-31
| | | | | | Commit f9143d102ffd0947ca904c62b1d3d6fd587e0c80 falsified these. KaiGai Kohei
* Stamp 9.6rc1.REL9_6_RC1Tom Lane2016-08-29
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* Fix stray reference to the old genbki.sh script.Tom Lane2016-08-28
| | | | Per Tomas Vondra.
* Add macros to make AllocSetContextCreate() calls simpler and safer.Tom Lane2016-08-27
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | I found that half a dozen (nearly 5%) of our AllocSetContextCreate calls had typos in the context-sizing parameters. While none of these led to especially significant problems, they did create minor inefficiencies, and it's now clear that expecting people to copy-and-paste those calls accurately is not a great idea. Let's reduce the risk of future errors by introducing single macros that encapsulate the common use-cases. Three such macros are enough to cover all but two special-purpose contexts; those two calls can be left as-is, I think. While this patch doesn't in itself improve matters for third-party extensions, it doesn't break anything for them either, and they can gradually adopt the simplified notation over time. In passing, change TopMemoryContext to use the default allocation parameters. Formerly it could only be extended 8K at a time. That was probably reasonable when this code was written; but nowadays we create many more contexts than we did then, so that it's not unusual to have a couple hundred K in TopMemoryContext, even without considering various dubious code that sticks other things there. There seems no good reason not to let it use growing blocks like most other contexts. Back-patch to 9.6, mostly because that's still close enough to HEAD that it's easy to do so, and keeping the branches in sync can be expected to avoid some future back-patching pain. The bugs fixed by these changes don't seem to be significant enough to justify fixing them further back. Discussion: <21072.1472321324@sss.pgh.pa.us>
* Add a nonlocalized version of the severity field to client error messages.Tom Lane2016-08-26
| | | | | | | | | | | | | | | | | | | | This has been requested a few times, but the use-case for it was never entirely clear. The reason for adding it now is that transmission of error reports from parallel workers fails when NLS is active, because pq_parse_errornotice() wrongly assumes that the existing severity field is nonlocalized. There are other ways we could have fixed that, but the other options were basically kluges, whereas this way provides something that's at least arguably a useful feature along with the bug fix. Per report from Jakob Egger. Back-patch into 9.6, because otherwise parallel query is essentially unusable in non-English locales. The problem exists in 9.5 as well, but we don't want to risk changing on-the-wire behavior in 9.5 (even though the possibility of new error fields is specifically called out in the protocol document). It may be sufficient to leave the issue unfixed in 9.5, given the very limited usefulness of pq_parse_errornotice in that version. Discussion: <A88E0006-13CB-49C6-95CC-1A77D717213C@eggerapps.at>
* Fix improper repetition of previous results from a hashed aggregate.Tom Lane2016-08-24
| | | | | | | | | | | | | | | | | | | | | | ExecReScanAgg's check for whether it could re-use a previously calculated hashtable neglected the possibility that the Agg node might reference PARAM_EXEC Params that are not referenced by its input plan node. That's okay if the Params are in upper tlist or qual expressions; but if one appears in aggregate input expressions, then the hashtable contents need to be recomputed when the Param's value changes. To avoid unnecessary performance degradation in the case of a Param that isn't within an aggregate input, add logic to the planner to determine which Params are within aggregate inputs. This requires a new field in struct Agg, but fortunately we never write plans to disk, so this isn't an initdb-forcing change. Per report from Jeevan Chalke. This has been broken since forever, so back-patch to all supported branches. Andrew Gierth, with minor adjustments by me Report: <CAM2+6=VY8ykfLT5Q8vb9B6EbeBk-NGuLbT6seaQ+Fq4zXvrDcA@mail.gmail.com>
* Remove unnecessary #include.Kevin Grittner2016-08-24
| | | | | | Accidentally added in 8b65cf4c5edabdcae45ceaef7b9ac236879aae50. Pointed out by Álvaro Herrera
* In plpgsql, don't try to convert int2vector or oidvector to expanded array.Tom Lane2016-08-18
| | | | | | | | | | These types are storage-compatible with real arrays, but they don't support toasting, so of course they can't support expansion either. Per bug #14289 from Michael Overmeyer. Back-patch to 9.5 where expanded arrays were introduced. Report: <20160818174414.1529.37913@wrigleys.postgresql.org>
* Fix deletion of speculatively inserted TOAST on conflictAndres Freund2016-08-17
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | INSERT .. ON CONFLICT runs a pre-check of the possible conflicting constraints before performing the actual speculative insertion. In case the inserted tuple included TOASTed columns the ON CONFLICT condition would be handled correctly in case the conflict was caught by the pre-check, but if two transactions entered the speculative insertion phase at the same time, one would have to re-try, and the code for aborting a speculative insertion did not handle deleting the speculatively inserted TOAST datums correctly. TOAST deletion would fail with "ERROR: attempted to delete invisible tuple" as we attempted to remove the TOAST tuples using simple_heap_delete which reasoned that the given tuples should not be visible to the command that wrote them. This commit updates the heap_abort_speculative() function which aborts the conflicting tuple to use itself, via toast_delete, for deleting associated TOAST datums. Like before, the inserted toast rows are not marked as being speculative. This commit also adds a isolationtester spec test, exercising the relevant code path. Unfortunately 9.5 cannot handle two waiting sessions, and thus cannot execute this test. Reported-By: Viren Negi, Oskari Saarenmaa Author: Oskari Saarenmaa, edited a bit by me Bug: #14150 Discussion: <20160519123338.12513.20271@wrigleys.postgresql.org> Backpatch: 9.5, where ON CONFLICT was introduced
* Fix assorted places in psql to print version numbers >= 10 in new style.Tom Lane2016-08-16
| | | | | | | | | | | | | | | | | | | This is somewhat cosmetic, since as long as you know what you are looking at, "10.0" is a serviceable substitute for "10". But there is a potential for confusion between version numbers with minor numbers and those without --- we don't want people asking "why is psql saying 10.0 when my server is 10.2". Therefore, back-patch as far as practical, which turns out to be 9.3. I could have redone the patch to use fprintf(stderr) in place of psql_error(), but it seems more work than is warranted for branches that will be EOL or nearly so by the time v10 comes out. Although only psql seems to contain any code that needs this, I chose to put the support function into fe_utils, since it seems likely we'll need it in other client programs in future. (In 9.3-9.5, use dumputils.c, the predecessor of fe_utils/string_utils.c.) In HEAD, also fix the backend code that whines about loadable-library version mismatch. I don't see much need to back-patch that.
* Final pgindent + perltidy run for 9.6.Tom Lane2016-08-15
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* Remove bogus dependencies on NUMERIC_MAX_PRECISION.Tom Lane2016-08-14
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | NUMERIC_MAX_PRECISION is a purely arbitrary constraint on the precision and scale you can write in a numeric typmod. It might once have had something to do with the allowed range of a typmod-less numeric value, but at least since 9.1 we've allowed, and documented that we allowed, any value that would physically fit in the numeric storage format; which is something over 100000 decimal digits, not 1000. Hence, get rid of numeric_in()'s use of NUMERIC_MAX_PRECISION as a limit on the allowed range of the exponent in scientific-format input. That was especially silly in view of the fact that you can enter larger numbers as long as you don't use 'e' to do it. Just constrain the value enough to avoid localized overflow, and let make_result be the final arbiter of what is too large. Likewise adjust ecpg's equivalent of this code. Also get rid of numeric_recv()'s use of NUMERIC_MAX_PRECISION to limit the number of base-NBASE digits it would accept. That created a dump/restore hazard for binary COPY without doing anything useful; the wire-format limit on number of digits (65535) is about as tight as we would want. In HEAD, also get rid of pg_size_bytes()'s unnecessary intimacy with what the numeric range limit is. That code doesn't exist in the back branches. Per gripe from Aravind Kumar. Back-patch to all supported branches, since they all contain the documentation claim about allowed range of NUMERIC (cf commit cabf5d84b). Discussion: <2895.1471195721@sss.pgh.pa.us>
* Add SQL-accessible functions for inspecting index AM properties.Tom Lane2016-08-13
| | | | | | | | | | | | | | | | | | | | | Per discussion, we should provide such functions to replace the lost ability to discover AM properties by inspecting pg_am (cf commit 65c5fcd35). The added functionality is also meant to displace any code that was looking directly at pg_index.indoption, since we'd rather not believe that the bit meanings in that field are part of any client API contract. As future-proofing, define the SQL API to not assume that properties that are currently AM-wide or index-wide will remain so unless they logically must be; instead, expose them only when inquiring about a specific index or even specific index column. Also provide the ability for an index AM to override the behavior. In passing, document pg_am.amtype, overlooked in commit 473b93287. Andrew Gierth, with kibitzing by me and others Discussion: <87mvl5on7n.fsf@news-spur.riddles.org.uk>
* Stamp 9.6beta4.REL9_6_BETA4Tom Lane2016-08-08
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* Obstruct shell, SQL, and conninfo injection via database and role names.Noah Misch2016-08-08
| | | | | | | | | | | | | | | | Due to simplistic quoting and confusion of database names with conninfo strings, roles with the CREATEDB or CREATEROLE option could escalate to superuser privileges when a superuser next ran certain maintenance commands. The new coding rule for PQconnectdbParams() calls, documented at conninfo_array_parse(), is to pass expand_dbname=true and wrap literal database names in a trivial connection string. Escape zero-length values in appendConnStrVal(). Back-patch to 9.1 (all supported versions). Nathan Bossart, Michael Paquier, and Noah Misch. Reviewed by Peter Eisentraut. Reported by Nathan Bossart. Security: CVE-2016-5424
* Promote pg_dumpall shell/connstr quoting functions to src/fe_utils.Noah Misch2016-08-08
| | | | | | | | | | Rename these newly-extern functions with terms more typical of their new neighbors. No functional changes; a subsequent commit will use them in more places. Back-patch to 9.1 (all supported versions). Back branches lack src/fe_utils, so instead rename the functions in place; the subsequent commit will copy them into the other programs using them. Security: CVE-2016-5424
* Fix misestimation of n_distinct for a nearly-unique column with many nulls.Tom Lane2016-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If ANALYZE found no repeated non-null entries in its sample, it set the column's stadistinct value to -1.0, intending to indicate that the entries are all distinct. But what this value actually means is that the number of distinct values is 100% of the table's rowcount, and thus it was overestimating the number of distinct values by however many nulls there are. This could lead to very poor selectivity estimates, as for example in a recent report from Andreas Joseph Krogh. We should discount the stadistinct value by whatever we've estimated the nulls fraction to be. (That is what will happen if we choose to use a negative stadistinct for a column that does have repeated entries, so this code path was just inconsistent.) In addition to fixing the stadistinct entries stored by several different ANALYZE code paths, adjust the logic where get_variable_numdistinct() forces an "all distinct" estimate on the basis of finding a relevant unique index. Unique indexes don't reject nulls, so there's no reason to assume that the null fraction doesn't apply. Back-patch to all supported branches. Back-patching is a bit of a judgment call, but this problem seems to affect only a few users (else we'd have identified it long ago), and it's bad enough when it does happen that destabilizing plan choices in a worse direction seems unlikely. Patch by me, with documentation wording suggested by Dean Rasheed Report: <VisenaEmail.26.df42f82acae38a58.156463942b8@tc7-visena> Discussion: <16143.1470350371@sss.pgh.pa.us>
* Fix TOAST access failure in RETURNING queries.Tom Lane2016-08-07
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Discussion of commit 3e2f3c2e4 exposed a problem that is of longer standing: since we don't detoast data while sticking it into a portal's holdStore for PORTAL_ONE_RETURNING and PORTAL_UTIL_SELECT queries, and we release the query's snapshot as soon as we're done loading the holdStore, later readout of the holdStore can do TOAST fetches against data that can no longer be seen by any of the session's live snapshots. This means that a concurrent VACUUM could remove the TOAST data before we can fetch it. Commit 3e2f3c2e4 exposed the problem by showing that sometimes we had *no* live snapshots while fetching TOAST data, but we'd be at risk anyway. I believe this code was all right when written, because our management of a session's exposed xmin was such that the TOAST references were safe until end of transaction. But that's no longer true now that we can advance or clear our PGXACT.xmin intra-transaction. To fix, copy the query's snapshot during FillPortalStore() and save it in the Portal; release it only when the portal is dropped. This essentially implements a policy that we must hold a relevant snapshot whenever we access potentially-toasted data. We had already come to that conclusion in other places, cf commits 08e261cbc94ce9a7 and ec543db77b6b72f2. I'd have liked to add a regression test case for this, but I didn't see a way to make one that's not unreasonably bloated; it seems to require returning a toasted value to the client, and those will be big. In passing, improve PortalRunUtility() so that it positively verifies that its ending PopActiveSnapshot() call will pop the expected snapshot, removing a rather shaky assumption about which utility commands might do their own PopActiveSnapshot(). There's no known bug here, but now that we're actively referencing the snapshot it's almost free to make this code a bit more bulletproof. We might want to consider back-patching something like this into older branches, but it would be prudent to let it prove itself more in HEAD beforehand. Discussion: <87vazemeda.fsf@credativ.de>
* Fix copy-and-pasteo in 81c766b3fd41c78c634d78ebae8d316808dfc630.Tom Lane2016-08-05
| | | | Report: <57A4E6DF.8070209@dunslane.net>
* Change InitToastSnapshot to a macro.Robert Haas2016-08-05
| | | | | | | | | tqual.h is included in some front-end compiles, and a static inline breaks on buildfarm member castoroides. Since the macro is never referenced, it should dodge that problem, although this doesn't seem like the cleanest way of hiding things from front-end compiles. Report and review by Tom Lane; patch by me.
* Prevent "snapshot too old" from trying to return pruned TOAST tuples.Robert Haas2016-08-03
| | | | | | | | | | | | | Previously, we tested for MVCC snapshots to see whether they were too old, but not TOAST snapshots, which can lead to complaints about missing TOAST chunks if those chunks are subject to early pruning. Ideally, the threshold lsn and timestamp for a TOAST snapshot would be that of the corresponding MVCC snapshot, but since we have no way of deciding which MVCC snapshot was used to fetch the TOAST pointer, use the oldest active or registered snapshot instead. Reported by Andres Freund, who also sketched out what the fix should look like. Patch by me, reviewed by Amit Kapila.
* Make INSERT-from-multiple-VALUES-rows handle targetlist indirection better.Tom Lane2016-08-03
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Previously, if an INSERT with multiple rows of VALUES had indirection (array subscripting or field selection) in its target-columns list, the parser handled that by applying transformAssignedExpr() to each element of each VALUES row independently. This led to having ArrayRef assignment nodes or FieldStore nodes in each row of the VALUES RTE. That works for simple cases, but in bug #14265 Nuri Boardman points out that it fails if there are multiple assignments to elements/fields of the same target column. For such cases to work, rewriteTargetListIU() has to nest the ArrayRefs or FieldStores together to produce a single expression to be assigned to the column. But it failed to find them in the top-level targetlist and issued an error about "multiple assignments to same column". We could possibly fix this by teaching the rewriter to apply rewriteTargetListIU to each VALUES row separately, but that would be messy (it would change the output rowtype of the VALUES RTE, for example) and inefficient. Instead, let's fix the parser so that the VALUES RTE outputs are just the user-specified values, cast to the right type if necessary, and then the ArrayRefs or FieldStores are applied in the top-level targetlist to Vars representing the RTE's outputs. This is the same parsetree representation already used for similar cases with INSERT/SELECT syntax, so it allows simplifications in ruleutils.c, which no longer needs to treat INSERT-from-multiple-VALUES as its own special case. This implementation works by applying transformAssignedExpr to the VALUES entries as before, and then stripping off any ArrayRefs or FieldStores it adds. With lots of VALUES rows it would be noticeably more efficient to not add those nodes in the first place. But that's just an optimization not a bug fix, and there doesn't seem to be any good way to do it without significant refactoring. (A non-invasive answer would be to apply transformAssignedExpr + stripping to just the first VALUES row, and then just forcibly cast remaining rows to the same data types exposed in the first row. But this way would lead to different, not-INSERT-specific errors being reported in casting failure cases, so it doesn't seem very nice.) So leave that for later; this patch at least isn't making the per-row parsing work worse, and it does make the finished parsetree smaller, saving rewriter and planner work. Catversion bump because stored rules containing such INSERTs would need to change. Because of that, no back-patch, even though this is a very long-standing bug. Report: <20160727005725.7438.26021@wrigleys.postgresql.org> Discussion: <9578.1469645245@sss.pgh.pa.us>
* Minor cleanup for access/transam/parallel.c.Tom Lane2016-08-01
| | | | | | | | | | | | | | | | | | | | ParallelMessagePending *must* be marked volatile, because it's set by a signal handler. On the other hand, it's pointless for HandleParallelMessageInterrupt to save/restore errno; that must be, and is, done at the outer level of the SIGUSR1 signal handler. Calling CHECK_FOR_INTERRUPTS() inside HandleParallelMessages, which itself is called from CHECK_FOR_INTERRUPTS(), seems both useless and hazardous. The comment claiming that this is needed to handle the error queue going away is certainly misguided, in any case. Improve a couple of error message texts, and use ERRCODE_OBJECT_NOT_IN_PREREQUISITE_STATE to report loss of parallel worker connection, since that's what's used in e.g. tqueue.c. (Maybe it would be worth inventing a dedicated ERRCODE for this type of failure? But I do not think ERRCODE_INTERNAL_ERROR is appropriate.) Minor stylistic cleanups.
* Don't CHECK_FOR_INTERRUPTS between WaitLatch and ResetLatch.Tom Lane2016-08-01
| | | | | | | | | | | | | | | | | | | | | | | | | | | This coding pattern creates a race condition, because if an interesting interrupt happens after we've checked InterruptPending but before we reset our latch, the latch-setting done by the signal handler would get lost, and then we might block at WaitLatch in the next iteration without ever noticing the interrupt condition. You can put the CHECK_FOR_INTERRUPTS before WaitLatch or after ResetLatch, but not between them. Aside from fixing the bugs, add some explanatory comments to latch.h to perhaps forestall the next person from making the same mistake. In HEAD, also replace gather_readnext's direct call of HandleParallelMessages with CHECK_FOR_INTERRUPTS. It does not seem clean or useful for this one caller to bypass ProcessInterrupts and go straight to HandleParallelMessages; not least because that fails to consider the InterruptPending flag, resulting in useless work both here (if InterruptPending isn't set) and in the next CHECK_FOR_INTERRUPTS call (if it is). This thinko seems to have been introduced in the initial coding of storage/ipc/shm_mq.c (commit ec9037df2), and then blindly copied into all the subsequent parallel-query support logic. Back-patch relevant hunks to 9.4 to extirpate the error everywhere. Discussion: <1661.1469996911@sss.pgh.pa.us>
* Remove unused arguments from pg_replication_origin_xact_reset function.Fujii Masao2016-08-02
| | | | | | | | | | | | | | | The document specifies that pg_replication_origin_xact_reset function doesn't have any argument variables. But previously it was actually defined so as to have two argument variables, though they were not used at all. That is, the pg_proc entry for that function was incorrect. This patch fixes the pg_proc entry and removes those two arguments from the function definition. No back-patch because this change needs a catalog version bump although the issue exists in 9.5 as well. Instead, a note about those unused argument variables will be added to 9.5 document later. Catalog version bumped due to the change of pg_proc.
* Fix worst memory leaks in tqueue.c.Tom Lane2016-07-29
| | | | | | | | | | | | | | | | | | | | | | | | | TupleQueueReaderNext() leaks like a sieve if it has to do any tuple disassembly/reconstruction. While we could try to clean up its allocations piecemeal, it seems like a better idea just to insist that it should be run in a short-lived memory context, so that any transient space goes away automatically. I chose to have nodeGather.c switch into its existing per-tuple context before the call, rather than inventing a separate context inside tqueue.c. This is sufficient to stop all leakage in the simple case I exhibited earlier today (see link below), but it does not deal with leaks induced in more complex cases by tqueue.c's insistence on using TopMemoryContext for data that it's not actually trying hard to keep track of. That issue is intertwined with another major source of inefficiency, namely failure to cache lookup results across calls, so it seems best to deal with it separately. In passing, improve some comments, and modify gather_readnext's method for deciding when it's visited all the readers so that it's more obviously correct. (I'm not actually convinced that the previous code *is* correct in the case of a reader deletion; it certainly seems fragile.) Discussion: <32763.1469821037@sss.pgh.pa.us>
* Fix pq_putmessage_noblock() to not block.Tom Lane2016-07-29
| | | | | | | | | | | | An evident copy-and-pasteo in commit 2bd9e412f broke the non-blocking aspect of pq_putmessage_noblock(), causing it to behave identically to pq_putmessage(). That function is nowadays used only in walsender.c, so that the net effect was to cause walsenders to hang up waiting for the receiver in situations where they should not. Kyotaro Horiguchi Patch: <20160728.185228.58375982.horiguchi.kyotaro@lab.ntt.co.jp>