21 Commits (1e7c4bb0049732ece651d993d03bb6772e5d281a)

Author	SHA1	Message	Date
Tom Lane	1e7c4bb004	Change unknown-type literals to type text in SELECT and RETURNING lists. ... Previously, we left such literals alone if the query or subquery had no properties forcing a type decision to be made (such as an ORDER BY or DISTINCT clause using that output column). This meant that "unknown" could be an exposed output column type, which has never been a great idea because it could result in strange failures later on. For example, an outer query that tried to do any operations on an unknown-type subquery output would generally fail with some weird error like "failed to find conversion function from unknown to text" or "could not determine which collation to use for string comparison". Also, if the case occurred in a CREATE VIEW's query then the view would have an unknown-type column, causing similar failures in queries trying to use the view. To fix, at the tail end of parse analysis of a query, forcibly convert any remaining "unknown" literals in its SELECT or RETURNING list to type text. However, provide a switch to suppress that, and use it in the cases of SELECT inside a set operation or INSERT command. In those cases we already had type resolution rules that make use of context information from outside the subquery proper, and we don't want to change that behavior. Also, change creation of an unknown-type column in a relation from a warning to a hard error. The error should be unreachable now in CREATE VIEW or CREATE MATVIEW, but it's still possible to explicitly say "unknown" in CREATE TABLE or CREATE (composite) TYPE. We want to forbid that because it's nothing but a foot-gun. This change creates a pg_upgrade failure case: a matview that contains an unknown-type column can't be pg_upgraded, because reparsing the matview's defining query will now decide that the column is of type text, which doesn't match the cstring-like storage that the old materialized column would actually have. Add a checking pass to detect that. While at it, we can detect tables or composite types that would fail, essentially for free. Those would fail safely anyway later on, but we might as well fail earlier. This patch is by me, but it owes something to previous investigations by Rahila Syed. Also thanks to Ashutosh Bapat and Michael Paquier for review. Discussion: https://postgr.es/m/CAH2L28uwwbL9HUM-WR=hromW1Cvamkn7O-g8fPY2m=_7muJ0oA@mail.gmail.com	9 years ago
Tom Lane	0b78106cd4	Fix reporting of column typmods for multi-row VALUES constructs. ... 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. It's cheap for transformValuesClause to determine the common typmod while transforming a multi-row VALUES, but it'd be less cheap for expandRTE() and get_rte_attribute_type() to re-determine that info every time they're asked --- possibly a lot less cheap, if the VALUES has many rows. Therefore, the best fix is to record the common typmods explicitly in a list in the VALUES RTE, as we were already doing for column collations. This looks quite a bit like what we're doing for CTE RTEs, so we can save a little bit of space and code by unifying the representation for those two RTE types. They both now share coltypes/coltypmods/colcollations fields. (At some point it might seem desirable to populate those fields for all RTE types; but right now it looks like constructing them for other RTE types would add more code and cycles than it would save.) The RTE change requires a catversion bump, so this fix is only usable in HEAD. If we fix this at all in the back branches, the patch will need to look quite different. Report: https://postgr.es/m/20161205143037.4377.60754@wrigleys.postgresql.org Discussion: https://postgr.es/m/27429.1480968538@sss.pgh.pa.us	9 years ago
Tom Lane	1f7c85b820	Fix ruleutils.c's dumping of ScalarArrayOpExpr containing an EXPR_SUBLINK. ... When we shoehorned "x op ANY (array)" into the SQL syntax, we created a fundamental ambiguity as to the proper treatment of a sub-SELECT on the righthand side: perhaps what's meant is to compare x against each row of the sub-SELECT's result, or perhaps the sub-SELECT is meant as a scalar sub-SELECT that delivers a single array value whose members should be compared against x. The grammar resolves it as the former case whenever the RHS is a select_with_parens, making the latter case hard to reach --- but you can get at it, with tricks such as attaching a no-op cast to the sub-SELECT. Parse analysis would throw away the no-op cast, leaving a parsetree with an EXPR_SUBLINK SubLink directly under a ScalarArrayOpExpr. ruleutils.c was not clued in on this fine point, and would naively emit "x op ANY ((SELECT ...))", which would be parsed as the first alternative, typically leading to errors like "operator does not exist: text = text[]" during dump/reload of a view or rule containing such a construct. To fix, emit a no-op cast when dumping such a parsetree. This might well be exactly what the user wrote to get the construct accepted in the first place; and even if she got there with some other dodge, it is a valid representation of the parsetree. Per report from Karl Czajkowski. He mentioned only a case involving RLS policies, but actually the problem is very old, so back-patch to all supported branches. Report: <20160421001832.GB7976@moraine.isi.edu>	10 years ago
Tom Lane	8004953b5a	Speed up ruleutils' name de-duplication code, and fix overlength-name case. ... Since commit 11e131854f, ruleutils.c has attempted to ensure that each RTE in a query or plan tree has a unique alias name. However, the code that was added for this could be quite slow, even as bad as O(N^3) if N identical RTE names must be replaced, as noted by Jeff Janes. Improve matters by building a transient hash table within set_rtable_names. The hash table in itself reduces the cost of detecting a duplicate from O(N) to O(1), and we can save another factor of N by storing the number of de-duplicated names already created for each entry, so that we don't have to re-try names already created. This way is probably a bit slower overall for small range tables, but almost by definition, such cases should not be a performance problem. In principle the same problem applies to the column-name-de-duplication code; but in practice that seems to be less of a problem, first because N is limited since we don't support extremely wide tables, and second because duplicate column names within an RTE are fairly rare, so that in practice the cost is more like O(N^2) not O(N^3). It would be very much messier to fix the column-name code, so for now I've left that alone. An independent problem in the same area was that the de-duplication code paid no attention to the identifier length limit, and would happily produce identifiers that were longer than NAMEDATALEN and wouldn't be unique after truncation to NAMEDATALEN. This could result in dump/reload failures, or perhaps even views that silently behaved differently than before. We can fix that by shortening the base name as needed. Fix it for both the relation and column name cases. In passing, check for interrupts in set_rtable_names, just in case it's still slow enough to be an issue. Back-patch to 9.3 where this code was introduced.	10 years ago
Tom Lane	7745bc352a	Fix ruleutils.c's dumping of whole-row Vars in ROW() and VALUES() contexts. ... Normally ruleutils prints a whole-row Var as "foo.*". We already knew that that doesn't work at top level of a SELECT list, because the parser would treat the "*" as a directive to expand the reference into separate columns, not a whole-row Var. However, Joshua Yanovski points out in bug #13776 that the same thing happens at top level of a ROW() construct; and some nosing around in the parser shows that the same is true in VALUES(). Hence, apply the same workaround already devised for the SELECT-list case, namely to add a forced cast to the appropriate rowtype in these cases. (The alternative of just printing "foo" was rejected because it is difficult to avoid ambiguity against plain columns named "foo".) Back-patch to all supported branches.	10 years ago
Tom Lane	9b35ddce93	Partial fix for dropped columns in functions returning composite. ... When a view has a function-returning-composite in FROM, and there are some dropped columns in the underlying composite type, ruleutils.c printed junk in the column alias list for the reconstructed FROM entry. Before 9.3, this was prevented by doing get_rte_attribute_is_dropped tests while printing the column alias list; but that solution is not currently available to us for reasons I'll explain below. Instead, check for empty-string entries in the alias list, which can only exist if that column position had been dropped at the time the view was made. (The parser fills in empty strings to preserve the invariant that the aliases correspond to physical column positions.) While this is sufficient to handle the case of columns dropped before the view was made, we have still got issues with columns dropped after the view was made. In particular, the view could contain Vars that explicitly reference such columns! The dependency machinery really ought to refuse the column drop attempt in such cases, as it would do when trying to drop a table column that's explicitly referenced in views. However, we currently neglect to store dependencies on columns of composite types, and fixing that is likely to be too big to be back-patchable (not to mention that existing views in existing databases would not have the needed pg_depend entries anyway). So I'll leave that for a separate patch. Pre-9.3, ruleutils would print such Vars normally (with their original column names) even though it suppressed their entries in the RTE's column alias list. This is certainly bogus, since the printed view definition would fail to reload, but at least it didn't crash. However, as of 9.3 the printed column alias list is tightly tied to the names printed for Vars; so we can't treat columns as dropped for one purpose and not dropped for the other. This is why we can't just put back the get_rte_attribute_is_dropped test: it results in an assertion failure if the view in fact contains any Vars referencing the dropped column. Once we've got dependencies preventing such cases, we'll probably want to do it that way instead of relying on the empty-string test used here. This fix turned up a very ancient bug in outfuncs/readfuncs, namely that T_String nodes containing empty strings were not dumped/reloaded correctly: the node was printed as "<>" which is read as a string value of <>. Since (per SQL) we disallow empty-string identifiers, such nodes don't occur normally, which is why we'd not noticed. (Such nodes aren't used for literal constants, just identifiers.) Per report from Marc Schablewski. Back-patch to 9.3 which is where the rule printing behavior changed. The dangling-variable case is broken all the way back, but that's not what his complaint is about.	12 years ago
Tom Lane	91e16b9806	Fix yet another corner case in dumping rules/views with USING clauses. ... ruleutils.c tries to cope with additions/deletions/renamings of columns in tables referenced by views, by means of adding machine-generated aliases to the printed form of a view when needed to preserve the original semantics. A recent blog post by Marko Tiikkaja pointed out a case I'd missed though: if one input of a join with USING is itself a join, there is nothing to stop the user from adding a column of the same name as the USING column to whichever side of the sub-join didn't provide the USING column. And then there'll be an error when the view is re-parsed, since now the sub-join exposes two columns matching the USING specification. We were catching a lot of related cases, but not this one, so add some logic to cope with it. Back-patch to 9.3, which is the first release that makes any serious attempt to cope with such cases (cf commit 2ffa740be and follow-ons).	12 years ago
Tom Lane	ef655663c5	Further hacking on ruleutils' new column-alias-assignment code. ... After further thought about implicit coercions appearing in a joinaliasvars list, I realized that they represent an additional reason why we might need to reference the join output column directly instead of referencing an underlying column. Consider SELECT x FROM t1 LEFT JOIN t2 USING (x) where t1.x is of type date while t2.x is of type timestamptz. The merged output variable is of type timestamptz, but it won't go to null when t2 does, therefore neither t1.x nor t2.x is a valid substitute reference. The code in get_variable() actually gets this case right, since it knows it shouldn't look through a coercion, but we failed to ensure that the unqualified output column name would be globally unique. To fix, modify the code that trawls for a dangerous situation so that it actually scans through an unnamed join's joinaliasvars list to see if there are any non-simple-Var entries.	13 years ago
Tom Lane	a7cd853b75	Change post-rewriter representation of dropped columns in joinaliasvars. ... It's possible to drop a column from an input table of a JOIN clause in a view, if that column is nowhere actually referenced in the view. But it will still be there in the JOIN clause's joinaliasvars list. We used to replace such entries with NULL Const nodes, which is handy for generation of RowExpr expansion of a whole-row reference to the view. The trouble with that is that it can't be distinguished from the situation after subquery pull-up of a constant subquery output expression below the JOIN. Instead, replace such joinaliasvars with null pointers (empty expression trees), which can't be confused with pulled-up expressions. expandRTE() still emits the old convention, though, for convenience of RowExpr generation and to reduce the risk of breaking extension code. In HEAD and 9.3, this patch also fixes a problem with some new code in ruleutils.c that was failing to cope with implicitly-casted joinaliasvars entries, as per recent report from Feike Steenbergen. That oversight was because of an inadequate description of the data structure in parsenodes.h, which I've now corrected. There were some pre-existing oversights of the same ilk elsewhere, which I believe are now all fixed.	13 years ago
Tom Lane	2ffa740be9	Fix ruleutils to cope with conflicts from adding/dropping/renaming columns. ... In commit 11e131854f, we improved the rule/view dumping code so that it would produce valid query representations even if some of the tables involved in a query had been renamed since the query was parsed. This patch extends that idea to fix problems that occur when individual columns are renamed, or added or dropped. As before, the core of the fix is to assign unique new aliases when a name conflict has been created. This is complicated by the JOIN USING feature, which requires the same column alias to be used in both input relations, but we can handle that with a sufficiently complex approach to assigning aliases. A fortiori, this patch takes care of situations where the query didn't have unique column names to begin with, such as in a recent complaint from Bryan Nuse. (Because of expansion of "SELECT *", re-parsing a dumped query can require column name uniqueness even though the original text did not.)	13 years ago
Tom Lane	11e131854f	Improve ruleutils.c's heuristics for dealing with rangetable aliases. ... The previous scheme had bugs in some corner cases involving tables that had been renamed since a view was made. This could result in dumped views that failed to reload or reloaded incorrectly, as seen in bug #7553 from Lloyd Albin, as well as in some pgsql-hackers discussion back in January. Also, its behavior for printing EXPLAIN plans was sometimes confusing because of willingness to use the same alias for multiple RTEs (it was Ashutosh Bapat's complaint about that aspect that started the January thread). To fix, ensure that each RTE in the query has a unique unqualified alias, by modifying the alias if necessary (we add "_" and digits as needed to create a non-conflicting name). Then we can just print its variables with that alias, avoiding the confusing and bug-prone scheme of sometimes schema-qualifying variable names. In EXPLAIN, it proves to be expedient to take the further step of only assigning such aliases to RTEs that are actually referenced in the query, since the planner has a habit of generating extra RTEs with the same alias in situations such as inheritance-tree expansion. Although this fixes a bug of very long standing, I'm hesitant to back-patch such a noticeable behavioral change. My experiments while creating a regression test convinced me that actually incorrect output (as opposed to confusing output) occurs only in very narrow cases, which is backed up by the lack of previous complaints from the field. So we may be better off living with it in released branches; and in any case it'd be smart to let this ripen awhile in HEAD before we consider back-patching it.	13 years ago
Robert Haas	0e4611c023	Add a security_barrier option for views. ... When a view is marked as a security barrier, it will not be pulled up into the containing query, and no quals will be pushed down into it, so that no function or operator chosen by the user can be applied to rows not exposed by the view. Views not configured with this option cannot provide robust row-level security, but will perform far better. Patch by KaiGai Kohei; original problem report by Heikki Linnakangas (in October 2009!). Review (in earlier versions) by Noah Misch and others. Design advice by Tom Lane and myself. Further review and cleanup by me.	14 years ago
Peter Eisentraut	fc946c39ae	Remove useless whitespace at end of lines	15 years ago
Bruce Momjian	ff1ea2173a	Allow CREATE OR REPLACE VIEW to add columns to the _end_ of the view. ... Robert Haas	17 years ago
Neil Conway	f5ab0a14ea	Add a "USING" clause to DELETE, which is equivalent to the FROM clause ... in UPDATE. We also now issue a NOTICE if a query has _any_ implicit range table entries -- in the past, we would only warn about implicit RTEs in SELECTs with at least one explicit RTE. As a result of the warning change, 25 of the regression tests had to be updated. I also took the opportunity to remove some bogus whitespace differences between some of the float4 and float8 variants. I believe I have correctly updated all the platform-specific variants, but let me know if that's not the case. Original patch for DELETE ... USING from Euler Taveira de Oliveira, reworked by Neil Conway.	21 years ago
Neil Conway	73f630500b	Add support for temporary views, including documentation and regression ... tests. Contributed by Koju Iijima, review from Neil Conway, Gavin Sherry and Tom Lane. Also, fix error in description of WITH CHECK OPTION clause in the CREATE VIEW reference page: it should be "CASCADED", not "CASCADE".	21 years ago
Tom Lane	42ce74bf17	COMMENT ON casts, conversions, languages, operator classes, and ... large objects. Dump all these in pg_dump; also add code to pg_dump user-defined conversions. Make psql's large object code rely on the backend for inserting/deleting LOB comments, instead of trying to hack pg_description directly. Documentation and regression tests added. Christopher Kings-Lynne, code reviewed by Tom	22 years ago
Tom Lane	248c67d7ed	CREATE OR REPLACE VIEW, CREATE OR REPLACE RULE. ... Gavin Sherry, Neil Conway, and Tom Lane all got their hands dirty on this one ...	24 years ago
Tom Lane	2ae20ef98a	Update regression tests for ONLY and other recent changes.	26 years ago
Thomas G. Lockhart	c0cab6f4fa	Update format to add uniform headers on files.	26 years ago
Marc G. Fournier	588ae64c44	More splits and cleanups...	29 years ago