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2022-10-16Rename parser token REF to REF_P to avoid a symbol conflict.Tom Lane
In the latest version of Apple's macOS SDK, <sys/socket.h> fails to compile if "REF" is #define'd as something. Apple may or may not agree that this is a bug, and even if they do accept the bug report I filed, they probably won't fix it very quickly. In the meantime, our back branches will all fail to compile gram.y. v15 and HEAD currently escape the problem thanks to the refactoring done in 98e93a1fc, but that's purely accidental. Moreover, since that patch removed a widely-visible inclusion of <netdb.h>, back-patching it seems too likely to break third-party code. Instead, change the token's code name to REF_P, following our usual convention for naming parser tokens that are likely to have symbol conflicts. The effects of that should be localized to the grammar and immediately surrounding files, so it seems like a safer answer. Per project policy that we want to keep recently-out-of-support branches buildable on modern systems, back-patch all the way to 9.2. Discussion: https://postgr.es/m/1803927.1665938411@sss.pgh.pa.us
2022-09-20Suppress variable-set-but-not-used warnings from clang 15.Tom Lane
clang 15+ will issue a set-but-not-used warning when the only use of a variable is in autoincrements (e.g., "foo++;"). That's perfectly sensible, but it detects a few more cases that we'd not noticed before. Silence the warnings with our usual methods, such as PG_USED_FOR_ASSERTS_ONLY, or in one case by actually removing a useless variable. One thing that we can't nicely get rid of is that with %pure-parser, Bison emits "yynerrs" as a local variable that falls foul of this warning. To silence those, I inserted "(void) yynerrs;" in the top-level productions of affected grammars. Per recently-established project policy, this is a candidate for back-patching into out-of-support branches: it suppresses annoying compiler warnings but changes no behavior. Hence, back-patch to 9.5, which is as far as these patches go without issues. (A preliminary check shows that the prior branches need some other set-but-not-used cleanups too, so I'll leave them for another day.) Discussion: https://postgr.es/m/514615.1663615243@sss.pgh.pa.us
2020-12-01Ensure that expandTableLikeClause() re-examines the same table.Tom Lane
As it stood, expandTableLikeClause() re-did the same relation_openrv call that transformTableLikeClause() had done. However there are scenarios where this would not find the same table as expected. We hold lock on the LIKE source table, so it can't be renamed or dropped, but another table could appear before it in the search path. This explains the odd behavior reported in bug #16758 when cloning a table as a temp table of the same name. This case worked as expected before commit 502898192 introduced the need to open the source table twice, so we should fix it. To make really sure we get the same table, let's re-open it by OID not name. That requires adding an OID field to struct TableLikeClause, which is a little nervous-making from an ABI standpoint, but as long as it's at the end I don't think there's any serious risk. Per bug #16758 from Marc Boeren. Like the previous patch, back-patch to all supported branches. Discussion: https://postgr.es/m/16758-840e84a6cfab276d@postgresql.org
2020-11-19Further fixes for CREATE TABLE LIKE: cope with self-referential FKs.Tom Lane
Commit 502898192 was too careless about the order of execution of the additional ALTER TABLE operations generated by expandTableLikeClause. It just stuck them all at the end, which seems okay for most purposes. But it falls down in the case where LIKE is importing a primary key or unique index and the outer CREATE TABLE includes a FOREIGN KEY constraint that needs to depend on that index. Weird as that is, it used to work, so we ought to keep it working. To fix, make parse_utilcmd.c insert LIKE clauses between index-creation and FK-creation commands in the transformed list of commands, and change utility.c so that the commands generated by expandTableLikeClause are executed immediately not at the end. One could imagine scenarios where this wouldn't work either; but currently expandTableLikeClause only makes column default expressions, CHECK constraints, and indexes, and this ordering seems fine for those. Per bug #16730 from Sofoklis Papasofokli. Like the previous patch, back-patch to all supported branches. Discussion: https://postgr.es/m/16730-b902f7e6e0276b30@postgresql.org
2020-10-07Fix optimization hazard in gram.y's makeOrderedSetArgs(), redux.Tom Lane
It appears that commit cf63c641c, which intended to prevent misoptimization of the result-building step in makeOrderedSetArgs, didn't go far enough: buildfarm member hornet's version of xlc is now optimizing back to the old, broken behavior in which list_length(directargs) is fetched only after list_concat() has changed that value. I'm not entirely convinced whether that's an undeniable compiler bug or whether it can be justified by a sufficiently aggressive interpretation of C sequence points. So let's just change the code to make it harder to misinterpret. Back-patch to all supported versions, just in case. Discussion: https://postgr.es/m/1830491.1601944935@sss.pgh.pa.us
2020-08-21Fix handling of CREATE TABLE LIKE with inheritance.Tom Lane
If a CREATE TABLE command uses both LIKE and traditional inheritance, Vars in CHECK constraints and expression indexes that are absorbed from a LIKE parent table tended to get mis-numbered, resulting in wrong answers and/or bizarre error messages (though probably not any actual crashes, thanks to validation occurring in the executor). In v12 and up, the same could happen to Vars in GENERATED expressions, even in cases with no LIKE clause but multiple traditional-inheritance parents. The cause of the problem for LIKE is that parse_utilcmd.c supposed it could renumber such Vars correctly during transformCreateStmt(), which it cannot since we have not yet accounted for columns added via inheritance. Fix that by postponing processing of LIKE INCLUDING CONSTRAINTS, DEFAULTS, GENERATED, INDEXES till after we've performed DefineRelation(). The error with GENERATED and multiple inheritance is a simple oversight in MergeAttributes(); it knows it has to renumber Vars in inherited CHECK constraints, but forgot to apply the same processing to inherited GENERATED expressions (a/k/a defaults). Per bug #16272 from Tom Gottfried. The non-GENERATED variants of the issue are ancient, presumably dating right back to the addition of CREATE TABLE LIKE; hence back-patch to all supported branches. Discussion: https://postgr.es/m/16272-6e32da020e9a9381@postgresql.org
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
2019-08-05Require the schema qualification in pg_temp.type_name(arg).Noah Misch
Commit aa27977fe21a7dfa4da4376ad66ae37cb8f0d0b5 introduced this restriction for pg_temp.function_name(arg); do likewise for types created in temporary schemas. Programs that this breaks should add "pg_temp." schema qualification or switch to arg::type_name syntax. Back-patch to 9.4 (all supported versions). Reviewed by Tom Lane. Reported by Tom Lane. Security: CVE-2019-10208
2019-04-10Fix backwards test in operator_precedence_warning logic.Tom Lane
Warnings about unary minus might have been wrong. It's a bit surprising that nobody noticed yet ... probably the precedence-warning feature hasn't really been used much in the field. Rikard Falkeborn Discussion: https://postgr.es/m/CADRDgG6fzA8A2oeygUw4=o7ywo4kvz26NxCSgpq22nMD73Bx4Q@mail.gmail.com
2019-02-24Fix ecpg bugs caused by missing semicolons in the backend grammar.Tom Lane
The Bison documentation clearly states that a semicolon is required after every grammar rule, and our scripts that generate ecpg's grammar from the backend's implicitly assumed this is true. But it turns out that only ancient versions of Bison actually enforce that. There have been a couple of rules without trailing semicolons in gram.y for some time, and as a consequence, ecpg's grammar was faulty and produced wrong output for the affected statements. To fix, add the missing semis, and add some cross-checks to ecpg's scripts so that they'll bleat if we mess this up again. The cases that were broken were: * "SET variable = DEFAULT" (but not "SET variable TO DEFAULT"), as well as allied syntaxes such as ALTER SYSTEM SET ... DEFAULT. These produced syntactically invalid output that the server would reject. * Multiple type names in DROP TYPE/DOMAIN commands. Only the first type name would be listed in the emitted command. Per report from Daisuke Higuchi. Back-patch to all supported versions. Discussion: https://postgr.es/m/1803D792815FC24D871C00D17AE95905DB51CE@g01jpexmbkw24
2019-02-15Fix support for CREATE TABLE IF NOT EXISTS AS EXECUTEMichael Paquier
The grammar IF NOT EXISTS for CTAS is supported since 9.5 and documented as such, however the case of using EXECUTE as query has never been covered as EXECUTE CTAS statements and normal CTAS statements are parsed separately. Author: Andreas Karlsson Discussion: https://postgr.es/m/2ddcc188-e37c-a0be-32bf-a56b07c3559e@proxel.se Backpatch-through: 9.5
2019-01-17Postpone aggregate checks until after collation is assigned.Andrew Gierth
Previously, parseCheckAggregates was run before assign_query_collations, but this causes problems if any expression has already had a collation assigned by some transform function (e.g. transformCaseExpr) before parseCheckAggregates runs. The differing collations would cause expressions not to be recognized as equal to the ones in the GROUP BY clause, leading to spurious errors about unaggregated column references. The result was that CASE expr WHEN val ... would fail when "expr" contained a GROUPING() expression or matched one of the group by expressions, and where collatable types were involved; whereas the supposedly identical CASE WHEN expr = val ... would succeed. Backpatch all the way; this appears to have been wrong ever since collations were introduced. Per report from Guillaume Lelarge, analysis and patch by me. Discussion: https://postgr.es/m/CAECtzeVSO_US8C2Khgfv54ZMUOBR4sWq+6_bLrETnWExHT=rFg@mail.gmail.com Discussion: https://postgr.es/m/87muo0k0c7.fsf@news-spur.riddles.org.uk
2018-08-23Fix lexing of standard multi-character operators in edge cases.Andrew Gierth
Commits c6b3c939b (which fixed the precedence of >=, <=, <> operators) and 865f14a2d (which added support for the standard => notation for named arguments) created a class of lexer tokens which look like multi-character operators but which have their own token IDs distinct from Op. However, longest-match rules meant that following any of these tokens with another operator character, as in (1<>-1), would cause them to be incorrectly returned as Op. The error here isn't immediately obvious, because the parser would usually still find the correct operator via the Op token, but there were more subtle problems: 1. If immediately followed by a comment or +-, >= <= <> would be given the old precedence of Op rather than the correct new precedence; 2. If followed by a comment, != would be returned as Op rather than as NOT_EQUAL, causing it not to be found at all; 3. If followed by a comment or +-, the => token for named arguments would be lexed as Op, causing the argument to be mis-parsed as a simple expression, usually causing an error. Fix by explicitly checking for the operators in the {operator} code block in addition to all the existing special cases there. Backpatch to 9.5 where the problem was introduced. Analysis and patch by me; review by Tom Lane. Discussion: https://postgr.es/m/87va851ppl.fsf@news-spur.riddles.org.uk
2018-08-23Reduce an unnecessary O(N^3) loop in lexer.Andrew Gierth
The lexer's handling of operators contained an O(N^3) hazard when dealing with long strings of + or - characters; it seems hard to prevent this case from being O(N^2), but the additional N multiplier was not needed. Backpatch all the way since this has been there since 7.x, and it presents at least a mild hazard in that trying to do Bind, PREPARE or EXPLAIN on a hostile query could take excessive time (without honouring cancels or timeouts) even if the query was never executed.
2018-08-04Fix INSERT ON CONFLICT UPDATE through a view that isn't just SELECT *.Tom Lane
When expanding an updatable view that is an INSERT's target, the rewriter failed to rewrite Vars in the ON CONFLICT UPDATE clause. This accidentally worked if the view was just "SELECT * FROM ...", as the transformation would be a no-op in that case. With more complicated view targetlists, this omission would often lead to "attribute ... has the wrong type" errors or even crashes, as reported by Mario De Frutos Dieguez. Fix by adding code to rewriteTargetView to fix up the data structure correctly. The easiest way to update the exclRelTlist list is to rebuild it from scratch looking at the new target relation, so factor the code for that out of transformOnConflictClause to make it sharable. In passing, avoid duplicate permissions checks against the EXCLUDED pseudo-relation, and prevent useless view expansion of that relation's dummy RTE. The latter is only known to happen (after this patch) in cases where the query would fail later due to not having any INSTEAD OF triggers for the view. But by exactly that token, it would create an unintended and very poorly tested state of the query data structure, so it seems like a good idea to prevent it from happening at all. This has been broken since ON CONFLICT was introduced, so back-patch to 9.5. Dean Rasheed, based on an earlier patch by Amit Langote; comment-kibitzing and back-patching by me Discussion: https://postgr.es/m/CAFYwGJ0xfzy8jaK80hVN2eUWr6huce0RU8AgU04MGD00igqkTg@mail.gmail.com
2018-05-21Fix SQL:2008 FETCH FIRST syntax to allow parameters.Andrew Gierth
OFFSET <x> ROWS FETCH FIRST <y> ROWS ONLY syntax is supposed to accept <simple value specification>, which includes parameters as well as literals. When this syntax was added all those years ago, it was done inconsistently, with <x> and <y> being different subsets of the standard syntax. Rectify that by making <x> and <y> accept the same thing, and allowing either a (signed) numeric literal or a c_expr there, which allows for parameters, variables, and parenthesized arbitrary expressions. Per bug #15200 from Lukas Eder. Backpatch all the way, since this has been broken from the start. Discussion: https://postgr.es/m/877enz476l.fsf@news-spur.riddles.org.uk Discussion: http://postgr.es/m/152647780335.27204.16895288237122418685@wrigleys.postgresql.org
2018-03-23Fix make rules that generate multiple output files.Tom Lane
For years, our makefiles have correctly observed that "there is no correct way to write a rule that generates two files". However, what we did is to provide empty rules that "generate" the secondary output files from the primary one, and that's not right either. Depending on the details of the creating process, the primary file might end up timestamped later than one or more secondary files, causing subsequent make runs to consider the secondary file(s) out of date. That's harmless in a plain build, since make will just re-execute the empty rule and nothing happens. But it's fatal in a VPATH build, since make will expect the secondary file to be rebuilt in the build directory. This would manifest as "file not found" failures during VPATH builds from tarballs, if we were ever unlucky enough to ship a tarball with apparently out-of-date secondary files. (It's not clear whether that has ever actually happened, but it definitely could.) To ensure that secondary output files have timestamps >= their primary's, change our makefile convention to be that we provide a "touch $@" action not an empty rule. Also, make sure that this rule actually gets invoked during a distprep run, else the hazard remains. It's been like this a long time, so back-patch to all supported branches. In HEAD, I skipped the changes in src/backend/catalog/Makefile, because those rules are due to get replaced soon in the bootstrap data format patch, and there seems no need to create a merge issue for that patch. If for some reason we fail to land that patch in v11, we'll need to back-fill the changes in that one makefile from v10. Discussion: https://postgr.es/m/18556.1521668179@sss.pgh.pa.us
2017-11-06Always require SELECT permission for ON CONFLICT DO UPDATE.Dean Rasheed
The update path of an INSERT ... ON CONFLICT DO UPDATE requires SELECT permission on the columns of the arbiter index, but it failed to check for that in the case of an arbiter specified by constraint name. In addition, for a table with row level security enabled, it failed to check updated rows against the table's SELECT policies when the update path was taken (regardless of how the arbiter index was specified). Backpatch to 9.5 where ON CONFLICT DO UPDATE and RLS were introduced. Security: CVE-2017-15099
2017-10-27Dept of second thoughts: keep aliasp_item in sync with tlistitem.Tom Lane
Commit d5b760ecb wasn't quite right, on second thought: if the caller didn't ask for column names then it would happily emit more Vars than if the caller did ask for column names. This is surely not a good idea. Advance the aliasp_item whether or not we're preparing a colnames list.
2017-10-27Fix crash when columns have been added to the end of a view.Tom Lane
expandRTE() supposed that an RTE_SUBQUERY subquery must have exactly as many non-junk tlist items as the RTE has column aliases for it. This was true at the time the code was written, and is still true so far as parse analysis is concerned --- but when the function is used during planning, the subquery might have appeared through insertion of a view that now has more columns than it did when the outer query was parsed. This results in a core dump if, for instance, we have to expand a whole-row Var that references the subquery. To avoid crashing, we can either stop expanding the RTE when we run out of aliases, or invent new aliases for the added columns. While the latter might be more useful, the former is consistent with what expandRTE() does for composite-returning functions in the RTE_FUNCTION case, so it seems like we'd better do it that way. Per bug #14876 from Samuel Horwitz. This has been busted since commit ff1ea2173 allowed views to acquire more columns, so back-patch to all supported branches. Discussion: https://postgr.es/m/20171026184035.1471.82810@wrigleys.postgresql.org
2017-08-03Add missing ALTER USER variantsPeter Eisentraut
ALTER USER ... SET did not support all the syntax variants of ALTER ROLE ... SET. Reported-by: Pavel Golub <pavel@microolap.com>
2017-06-27Re-allow SRFs and window functions within sub-selects within aggregates.Tom Lane
check_agg_arguments_walker threw an error upon seeing a SRF or window function, but that is too aggressive: if the function is within a sub-select then it's perfectly fine. I broke the SRF case in commit 0436f6bde by copying the logic for window functions ... but that was broken too, and had been since commit eaccfded9. Repair both cases in HEAD, and the window function case back to 9.3. 9.2 gets this right.
2017-05-29Allow NumericOnly to be "+ FCONST".Tom Lane
The NumericOnly grammar production accepted ICONST, + ICONST, - ICONST, FCONST, and - FCONST, but for some reason not + FCONST. This led to strange inconsistencies like regression=# set random_page_cost = +4; SET regression=# set random_page_cost = 4000000000; SET regression=# set random_page_cost = +4000000000; ERROR: syntax error at or near "4000000000" (because 4000000000 is too large to be an ICONST). While there's no actual functional reason to need to write a "+", if we allow it for integers it seems like we should allow it for numerics too. It's been like that forever, so back-patch to all supported branches. Discussion: https://postgr.es/m/30908.1496006184@sss.pgh.pa.us
2017-02-15Fix YA unwanted behavioral difference with operator_precedence_warning.Tom Lane
Jeff Janes noted that the error cursor position shown for some errors would vary when operator_precedence_warning is turned on. We'd prefer that option to have no undocumented effects, so this isn't desirable. To fix, make sure that an AEXPR_PAREN node has the same exprLocation as its child node. (Note: it would be a little cheaper to use @2 here instead of an exprLocation call, but there are cases where that wouldn't produce the identical answer, so don't do it like that.) Back-patch to 9.5 where this feature was introduced. Discussion: https://postgr.es/m/CAMkU=1ykK+VhhcQ4Ky8KBo9FoaUJH3f3rDQB8TkTXi-ZsBRUkQ@mail.gmail.com
2017-02-06Fix typos in comments.Heikki Linnakangas
Backpatch to all supported versions, where applicable, to make backpatching of future fixes go more smoothly. Josh Soref Discussion: https://www.postgresql.org/message-id/CACZqfqCf+5qRztLPgmmosr-B0Ye4srWzzw_mo4c_8_B_mtjmJQ@mail.gmail.com
2016-12-21Fix detection of unfinished Unicode surrogate pair at end of string.Tom Lane
The U&'...' and U&"..." syntaxes silently discarded a surrogate pair start (that is, a code between U+D800 and U+DBFF) if it occurred at the very end of the string. This seems like an obvious oversight, since we throw an error for every other invalid combination of surrogate characters, including the very same situation in E'...' syntax. This has been wrong since the pair processing was added (in 9.0), so back-patch to all supported branches. Discussion: https://postgr.es/m/19113.1482337898@sss.pgh.pa.us
2016-12-11Build backend/parser/scan.l and interfaces/ecpg/preproc/pgc.l standalone.Tom Lane
Back-patch commit 72b1e3a21 into the pre-9.6 branches. As noted in the original commit, this has some extra benefits: we can narrow the scope of the -Wno-error flag that's forced on scan.c. Also, since these grammar and lexer files are so large, splitting them into separate build targets should have some advantages in build speed, particularly in parallel or ccache'd builds. However, the real reason for doing this now is that it avoids symbol- redefinition warnings (or worse) with the latest version of flex. It's not unreasonable that people would want to compile our old branches with recent tools. Per report from Дилян Палаузов. Discussion: https://postgr.es/m/d845c1af-e18d-6651-178f-9f08cdf37e10@aegee.org
2016-12-09Fix reporting of column typmods for multi-row VALUES constructs.Tom Lane
expandRTE() and get_rte_attribute_type() reported the exprType() and exprTypmod() values of the expressions in the first row of the VALUES as being the column type/typmod returned by the VALUES RTE. That's fine for the data type, since we coerce all expressions in a column to have the same common type. But we don't coerce them to have a common typmod, so it was possible for rows after the first one to return values that violate the claimed column typmod. This leads to the incorrect result seen in bug #14448 from Hassan Mahmood, as well as some other corner-case misbehaviors. The desired behavior is the same as we use in other type-unification cases: report the common typmod if there is one, but otherwise return -1 indicating no particular constraint. We fixed this in HEAD by deriving the typmods during transformValuesClause and storing them in the RTE, but that's not a feasible solution in the back branches. Instead, just use a brute-force approach of determining the correct common typmod during expandRTE() and get_rte_attribute_type(). Simple testing says that that doesn't really cost much, at least not in common cases where expandRTE() is only used once per query. It turns out that get_rte_attribute_type() is typically never used at all on VALUES RTEs, so the inefficiency there is of no great concern. Report: https://postgr.es/m/20161205143037.4377.60754@wrigleys.postgresql.org Discussion: https://postgr.es/m/27429.1480968538@sss.pgh.pa.us
2016-12-04Don't mess up pstate->p_next_resno in transformOnConflictClause().Tom Lane
transformOnConflictClause incremented p_next_resno while generating the phony targetlist for the EXCLUDED pseudo-rel. Then that field got incremented some more during transformTargetList, possibly leading to free_parsestate concluding that we'd overrun the allowed length of a tlist, as reported by Justin Pryzby. We could fix this by resetting p_next_resno to 1 after using it for the EXCLUDED pseudo-rel tlist, but it seems easier and less coupled to other places if we just don't use that field at all in this loop. (Note that this doesn't change anything about the resnos that end up appearing in the main target list, because those are all replaced with target-column numbers by updateTargetListEntry.) In passing, fix incorrect type OID assigned to the whole-row Var for "EXCLUDED.*" (somehow this escaped having any bad consequences so far, but it's certainly wrong); remove useless assignment to var->location; pstrdup the column names in case of a relcache flush; and improve nearby comments. Back-patch to 9.5 where ON CONFLICT was introduced. Report: https://postgr.es/m/20161204163237.GA8030@telsasoft.com
2016-11-20Prevent multicolumn expansion of "foo.*" in an UPDATE source expression.Tom Lane
Because we use transformTargetList() for UPDATE as well as SELECT tlists, the code accidentally tried to expand a "*" reference into several columns. This is nonsensical, because the UPDATE syntax provides exactly one target column to put the value into. The immediate result was that transformUpdateTargetList() got confused and reported "UPDATE target count mismatch --- internal error". It seems better to treat such a reference as a plain whole-row variable, as it would be in other contexts. (This could produce useful results when the target column is of composite type.) Fix by tweaking transformTargetList() to perform *-expansion only conditionally, depending on its exprKind parameter. Back-patch to 9.3. The problem exists further back, but a fix would be much more invasive before that, because transformTargetList() wasn't told what kind of list it was working on. Doesn't seem worth the trouble given the lack of field reports. (I only noticed it because I was checking the code while trying to improve the documentation about how we handle "foo.*".) Discussion: <4308.1479595330@sss.pgh.pa.us>
2016-07-28Improve documentation about CREATE TABLE ... LIKE.Tom Lane
The docs failed to explain that LIKE INCLUDING INDEXES would not preserve the names of indexes and associated constraints. Also, it wasn't mentioned that EXCLUDE constraints would be copied by this option. The latter oversight seems enough of a documentation bug to justify back-patching. In passing, do some minor copy-editing in the same area, and add an entry for LIKE under "Compatibility", since it's not exactly a faithful implementation of the standard's feature. Discussion: <20160728151154.AABE64016B@smtp.hushmail.com>
2016-06-03Fix grammar's AND/OR flattening to work with operator_precedence_warning.Tom Lane
It'd be good for "(x AND y) AND z" to produce a three-child AND node whether or not operator_precedence_warning is on, but that failed to happen when it's on because makeAndExpr() didn't look through the added AEXPR_PAREN node. This has no effect on generated plans because prepqual.c would flatten the AND nest anyway; but it does affect the number of parens printed in ruleutils.c, for example. I'd already fixed some similar hazards in parse_expr.c in commit abb164655, but didn't think to search gram.y for problems of this ilk. Per gripe from Jean-Pierre Pelletier. Report: <fa0535ec6d6428cfec40c7e8a6d11156@mail.gmail.com>
2016-04-21Fix unexpected side-effects of operator_precedence_warning.Tom Lane
The implementation of that feature involves injecting nodes into the raw parsetree where explicit parentheses appear. Various places in parse_expr.c that test to see "is this child node of type Foo" need to look through such nodes, else we'll get different behavior when operator_precedence_warning is on than when it is off. Note that we only need to handle this when testing untransformed child nodes, since the AEXPR_PAREN nodes will be gone anyway after transformExprRecurse. Per report from Scott Ribe and additional code-reading. Back-patch to 9.5 where this feature was added. Report: <ED37E303-1B0A-4CD8-8E1E-B9C4C2DD9A17@elevated-dev.com>
2016-01-22Remove new coupling between NAMEDATALEN and MAX_LEVENSHTEIN_STRLEN.Tom Lane
Commit e529cd4ffa605c6f introduced an Assert requiring NAMEDATALEN to be less than MAX_LEVENSHTEIN_STRLEN, which has been 255 for a long time. Since up to that instant we had always allowed NAMEDATALEN to be substantially more than that, this was ill-advised. It's debatable whether we need MAX_LEVENSHTEIN_STRLEN at all (versus putting a CHECK_FOR_INTERRUPTS into the loop), or whether it has to be so tight; but this patch takes the narrower approach of just not applying the MAX_LEVENSHTEIN_STRLEN limit to calls from the parser. Trusting the parser for this seems reasonable, first because the strings are limited to NAMEDATALEN which is unlikely to be hugely more than 256, and second because the maximum distance is tightly constrained by MAX_FUZZY_DISTANCE (though we'd forgotten to make use of that limit in one place). That means the cost is not really O(mn) but more like O(max(m,n)). Relaxing the limit for user-supplied calls is left for future research; given the lack of complaints to date, it doesn't seem very high priority. In passing, fix confusion between lengths-in-bytes and lengths-in-chars in comments and error messages. Per gripe from Kevin Day; solution suggested by Robert Haas. Back-patch to 9.5 where the unwanted restriction was introduced.
2016-01-21Add defenses against putting expanded objects into Const nodes.Tom Lane
Putting a reference to an expanded-format value into a Const node would be a bad idea for a couple of reasons. It'd be possible for the supposedly immutable Const to change value, if something modified the referenced variable ... in fact, if the Const's reference were R/W, any function that has the Const as argument might itself change it at runtime. Also, because datumIsEqual() is pretty simplistic, the Const might fail to compare equal to other Consts that it should compare equal to, notably including copies of itself. This could lead to unexpected planner behavior, such as "could not find pathkey item to sort" errors or inferior plans. I have not been able to find any way to get an expanded value into a Const within the existing core code; but Paul Ramsey was able to trigger the problem by writing a datatype input function that returns an expanded value. The best fix seems to be to establish a rule that varlena values being placed into Const nodes should be passed through pg_detoast_datum(). That will do nothing (and cost little) in normal cases, but it will flatten expanded values and thereby avoid the above problems. Also, it will convert short-header or compressed values into canonical format, which will avoid possible unexpected lack-of-equality issues for those cases too. And it provides a last-ditch defense against putting a toasted value into a Const, which we already knew was dangerous, cf commit 2b0c86b66563cf2f. (In the light of this discussion, I'm no longer sure that that commit provided 100% protection against such cases, but this fix should do it.) The test added in commit 65c3d05e18e7c530 to catch datatype input functions with unstable results would fail for functions that returned expanded values; but it seems a bit uncharitable to deem a result unstable just because it's expressed in expanded form, so revise the coding so that we check for bitwise equality only after applying pg_detoast_datum(). That's a sufficient condition anyway given the new rule about detoasting when forming a Const. Back-patch to 9.5 where the expanded-object facility was added. It's possible that this should go back further; but in the absence of clear evidence that there's any live bug in older branches, I'll refrain for now.
2015-11-16Message improvementsPeter Eisentraut
2015-10-28Message style improvementsPeter Eisentraut
Message style, plurals, quoting, spelling, consistency with similar messages
2015-10-04ALTER TABLE .. FORCE ROW LEVEL SECURITYStephen Frost
To allow users to force RLS to always be applied, even for table owners, add ALTER TABLE .. FORCE ROW LEVEL SECURITY. row_security=off overrides FORCE ROW LEVEL SECURITY, to ensure pg_dump output is complete (by default). Also add SECURITY_NOFORCE_RLS context to avoid data corruption when ALTER TABLE .. FORCE ROW SECURITY is being used. The SECURITY_NOFORCE_RLS security context is used only during referential integrity checks and is only considered in check_enable_rls() after we have already checked that the current user is the owner of the relation (which should always be the case during referential integrity checks). Back-patch to 9.5 where RLS was added.
2015-10-03Fix several bugs related to ON CONFLICT's EXCLUDED pseudo relation.Andres Freund
Four related issues: 1) attnos/varnos/resnos for EXCLUDED were out of sync when a column after one dropped in the underlying relation was referenced. 2) References to whole-row variables (i.e. EXCLUDED.*) lead to errors. 3) It was possible to reference system columns in the EXCLUDED pseudo relations, even though they would not have valid contents. 4) References to EXCLUDED were rewritten by the RLS machinery, as EXCLUDED was treated as if it were the underlying relation. To fix the first two issues, generate the excluded targetlist with dropped columns in mind and add an entry for whole row variables. Instead of unconditionally adding a wholerow entry we could pull up the expression if needed, but doing it unconditionally seems simpler. The wholerow entry is only really needed for ruleutils/EXPLAIN support anyway. The remaining two issues are addressed by changing the EXCLUDED RTE to have relkind = composite. That fits with EXCLUDED not actually being a real relation, and allows to treat it differently in the relevant places. scanRTEForColumn now skips looking up system columns when the RTE has a composite relkind; fireRIRrules() already had a corresponding check, thereby preventing RLS expansion on EXCLUDED. Also add tests for these issues, and improve a few comments around excluded handling in setrefs.c. Reported-By: Peter Geoghegan, Geoff Winkless Author: Andres Freund, Amit Langote, Peter Geoghegan Discussion: CAEzk6fdzJ3xYQZGbcuYM2rBd2BuDkUksmK=mY9UYYDugg_GgZg@mail.gmail.com, CAM3SWZS+CauzbiCEcg-GdE6K6ycHE_Bz6Ksszy8AoixcMHOmsA@mail.gmail.com Backpatch: 9.5, where ON CONFLICT was introduced
2015-08-21Rename 'cmd' to 'cmd_name' in CreatePolicyStmtStephen Frost
To avoid confusion, rename CreatePolicyStmt's 'cmd' to 'cmd_name', parse_policy_command's 'cmd' to 'polcmd', and AlterPolicy's 'cmd_datum' to 'polcmd_datum', per discussion with Noah and as a follow-up to his correction of copynodes/equalnodes handling of the CreatePolicyStmt 'cmd' field. Back-patch to 9.5 where the CreatePolicyStmt was introduced, as we are still only in alpha.
2015-08-09Remove gram.y's precedence declaration for OVERLAPS.Tom Lane
The allowed syntax for OVERLAPS, viz "row OVERLAPS row", is sufficiently constrained that we don't actually need a precedence declaration for OVERLAPS; indeed removing this declaration does not change the generated gram.c file at all. Let's remove it to avoid confusion about whether OVERLAPS has precedence or not. If we ever generalize what we allow for OVERLAPS, we might need to put back a precedence declaration for it, but we might want some other level than what it has today --- and leaving the declaration there would just risk confusion about whether that would be an incompatible change. Likewise, remove OVERLAPS from the documentation's precedence table. Per discussion with Noah Misch. Back-patch to 9.5 where we hacked up some nearby precedence decisions.
2015-07-29Create new ParseExprKind for use by policy expressions.Joe Conway
Policy USING and WITH CHECK expressions were using EXPR_KIND_WHERE for parse analysis, which results in inappropriate ERROR messages when the expression contains unsupported constructs such as aggregates. Create a new ParseExprKind called EXPR_KIND_POLICY and tailor the related messages to fit. Reported by Noah Misch. Reviewed by Dean Rasheed, Alvaro Herrera, and Robert Haas. Back-patch to 9.5 where RLS was introduced.
2015-07-26Fix flattening of nested grouping sets.Andres Freund
Previously nested grouping set specifications accidentally weren't flattened, but instead contained the nested specification as a element in the outer list. Fix this by, as actually documented in comments, concatenating the nested set specification into the outer one. Also add tests to prevent this from breaking again. Author: Andrew Gierth, with tests from Jeevan Chalke Reported-By: Jeevan Chalke Discussion: CAM2+6=V5YvuxB+EyN4iH=GbD-XTA435TCNvnDFSD--YvXs+pww@mail.gmail.com Backpatch: 9.5, where grouping sets were introduced
2015-07-25Redesign tablesample method API, and do extensive code review.Tom Lane
The original implementation of TABLESAMPLE modeled the tablesample method API on index access methods, which wasn't a good choice because, without specialized DDL commands, there's no way to build an extension that can implement a TSM. (Raw inserts into system catalogs are not an acceptable thing to do, because we can't undo them during DROP EXTENSION, nor will pg_upgrade behave sanely.) Instead adopt an API more like procedural language handlers or foreign data wrappers, wherein the only SQL-level support object needed is a single handler function identified by having a special return type. This lets us get rid of the supporting catalog altogether, so that no custom DDL support is needed for the feature. Adjust the API so that it can support non-constant tablesample arguments (the original coding assumed we could evaluate the argument expressions at ExecInitSampleScan time, which is undesirable even if it weren't outright unsafe), and discourage sampling methods from looking at invisible tuples. Make sure that the BERNOULLI and SYSTEM methods are genuinely repeatable within and across queries, as required by the SQL standard, and deal more honestly with methods that can't support that requirement. Make a full code-review pass over the tablesample additions, and fix assorted bugs, omissions, infelicities, and cosmetic issues (such as failure to put the added code stanzas in a consistent ordering). Improve EXPLAIN's output of tablesample plans, too. Back-patch to 9.5 so that we don't have to support the original API in production.
2015-07-24Fix bug around assignment expressions containing indirections.Andres Freund
Handling of assigned-to expressions with indirection (e.g. set f1[1] = 3) was broken for ON CONFLICT DO UPDATE. The problem was that ParseState was consulted to determine if an INSERT-appropriate or UPDATE-appropriate behavior should be used when transforming expressions with indirections. When the wrong path was taken the old row was substituted with NULL, leading to wrong results.. To fix remove p_is_update and only use p_is_insert to decide how to transform the assignment expression, and uset p_is_insert while parsing the on conflict statement. This isn't particularly pretty, but it's not any worse than before. Author: Peter Geoghegan, slightly edited by me Discussion: CAM3SWZS8RPvA=KFxADZWw3wAHnnbxMxDzkEC6fNaFc7zSm411w@mail.gmail.com Backpatch: 9.5, where the feature was introduced
2015-06-27Avoid passing NULL to memcmp() in lookups of zero-argument functions.Tom Lane
A few places assumed they could pass NULL for the argtypes array when looking up functions known to have zero arguments. At first glance it seems that this should be safe enough, since memcmp() is surely not allowed to fetch any bytes if its count argument is zero. However, close reading of the C standard says that such calls have undefined behavior, so we'd probably best avoid it. Since the number of places doing this is quite small, and some other places looking up zero-argument functions were already passing dummy arrays, let's standardize on the latter solution rather than hacking the function lookup code to avoid calling memcmp() in these cases. I also added Asserts to catch any future violations of the new rule. Given the utter lack of any evidence that this actually causes any problems in the field, I don't feel a need to back-patch this change. Per report from Piotr Stefaniak, though this is not his patch.
2015-05-23pgindent run for 9.5Bruce Momjian
2015-05-20Another typo fix.Tom Lane
In the spirit of the season.
2015-05-20Collection of typo fixes.Heikki Linnakangas
Use "a" and "an" correctly, mostly in comments. Two error messages were also fixed (they were just elogs, so no translation work required). Two function comments in pg_proc.h were also fixed. Etsuro Fujita reported one of these, but I found a lot more with grep. Also fix a few other typos spotted while grepping for the a/an typos. For example, "consists out of ..." -> "consists of ...". Plus a "though"/ "through" mixup reported by Euler Taveira. Many of these typos were in old code, which would be nice to backpatch to make future backpatching easier. But much of the code was new, and I didn't feel like crafting separate patches for each branch. So no backpatching.