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path: root/src/backend/optimizer/util/clauses.c
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* Modify error context callback functions to not assume that they can fetchTom Lane2010-03-191-51/+54
| | | | | | | | | | | | | | | | | | catalog entries via SearchSysCache and related operations. Although, at the time that these callbacks are called by elog.c, we have not officially aborted the current transaction, it still seems rather risky to initiate any new catalog fetches. In all these cases the needed information is readily available in the caller and so it's just a matter of a bit of extra notation to pass it to the callback. Per crash report from Dennis Koegel. I've concluded that the real fix for his problem is to clear the error context stack at entry to proc_exit, but it still seems like a good idea to make the callbacks a bit less fragile for other cases. Backpatch to 8.4. We could go further back, but the patch doesn't apply cleanly. In the absence of proof that this fixes something and isn't just paranoia, I'm not going to expend the effort.
* pgindent run for 9.0Bruce Momjian2010-02-261-32/+32
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* Wrap calls to SearchSysCache and related functions using macros.Robert Haas2010-02-141-10/+5
| | | | | | | | | | | | The purpose of this change is to eliminate the need for every caller of SearchSysCache, SearchSysCacheCopy, SearchSysCacheExists, GetSysCacheOid, and SearchSysCacheList to know the maximum number of allowable keys for a syscache entry (currently 4). This will make it far easier to increase the maximum number of keys in a future release should we choose to do so, and it makes the code shorter, too. Design and review by Tom Lane.
* Fix thinko in my recent change to put an explicit argisrow field in NullTest:Tom Lane2010-01-191-6/+8
| | | | | | when the planner splits apart a ROW(...) IS NULL test, the argisrow values of the component tests have to be determined from the component field types, not copied from the original NullTest (in which argisrow is surely true).
* Update copyright for the year 2010.Bruce Momjian2010-01-021-2/+2
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* Add an "argisrow" field to NullTest nodes, following a plan made way back inTom Lane2010-01-011-5/+7
| | | | | | 8.2beta but never carried out. This avoids repetitive tests of whether the argument is of scalar or composite type. Also, be a bit more paranoid about composite arguments in some places where we previously weren't checking.
* Support ORDER BY within aggregate function calls, at long last providing aTom Lane2009-12-151-9/+10
| | | | | | | | | | | | | non-kluge method for controlling the order in which values are fed to an aggregate function. At the same time eliminate the old implementation restriction that DISTINCT was only supported for single-argument aggregates. Possibly release-notable behavioral change: formerly, agg(DISTINCT x) dropped null values of x unconditionally. Now, it does so only if the agg transition function is strict; otherwise nulls are treated as DISTINCT normally would, ie, you get one copy. Andrew Gierth, reviewed by Hitoshi Harada
* Fix a bug introduced when set-returning SQL functions were made inline-able:Tom Lane2009-12-141-5/+17
| | | | | | | | | | | | | | we have to cope with the possibility that the declared result rowtype contains dropped columns. This fails in 8.4, as per bug #5240. While at it, be more paranoid about inserting binary coercions when inlining. The pre-8.4 code did not really need to worry about that because it could not inline at all in any case where an added coercion could change the behavior of the function's statement. However, when inlining a SRF we allow sorting, grouping, and set-ops such as UNION. In these cases, modifying one of the targetlist entries that the sort/group/setop depends on could conceivably change the behavior of the function's statement --- so don't inline when such a case applies.
* Support use of function argument names to identify which actual argumentsTom Lane2009-10-081-71/+255
| | | | | | | match which function parameters. The syntax uses AS, for example funcname(value AS arg1, anothervalue AS arg2) Pavel Stehule
* Teach simplify_boolean_equality to simplify the forms foo <> true andTom Lane2009-07-201-16/+40
| | | | | | | | foo <> false, along with its previous duties of simplifying foo = true and foo = false. (All of these are equivalent to just foo or NOT foo as the case may be.) It's not clear how often this is really useful; but it costs almost nothing to do, and it seems some people think we should be smart about such cases. Per recent bug report.
* 8.4 pgindent run, with new combined Linux/FreeBSD/MinGW typedef listBruce Momjian2009-06-111-47/+48
| | | | provided by Andrew.
* Get rid of the rather fuzzily defined FlattenedSubLink node type in favor ofTom Lane2009-02-251-37/+1
| | | | | | | | | making pull_up_sublinks() construct a full-blown JoinExpr tree representation of IN/EXISTS SubLinks that it is able to convert to semi or anti joins. This makes pull_up_sublinks() a shade more complex, but the gain in semantic clarity is worth it. I still have more to do in this area to address the previously-discussed problems, but this commit in itself fixes at least one bug in HEAD, as shown by added regression test case.
* Arrange for function default arguments to be processed properly in expressionsTom Lane2009-01-091-3/+10
| | | | | | | that are set up for execution with ExecPrepareExpr rather than going through the full planner process. By introducing an explicit notion of "expression planning", this patch also lays a bit of groundwork for maybe someday allowing sub-selects in standalone expressions.
* Fix an oversight in the function-default-arguments patch: after adding someTom Lane2009-01-061-7/+24
| | | | | | | default expressions to a function call, eval_const_expressions must recurse on those expressions. Else they don't get simplified, and in particular we fail to insert additional default arguments if any functions needing defaults are in there. Per report from Rushabh Lathia.
* Update copyright for 2009.Bruce Momjian2009-01-011-2/+2
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* Support window functions a la SQL:2008.Tom Lane2008-12-281-2/+122
| | | | Hitoshi Harada, with some kibitzing from Heikki and Tom.
* Code review for function default parameters patch. Fix numerous problems asTom Lane2008-12-181-12/+96
| | | | | per recent discussions. In passing this also fixes a couple of bugs in the previous variadic-parameters patch.
* Add a concept of "placeholder" variables to the planner. These are variablesTom Lane2008-10-211-1/+28
| | | | | | | | | | | | | | | | | | | that represent some expression that we desire to compute below the top level of the plan, and then let that value "bubble up" as though it were a plain Var (ie, a column value). The immediate application is to allow sub-selects to be flattened even when they are below an outer join and have non-nullable output expressions. Formerly we couldn't flatten because such an expression wouldn't properly go to NULL when evaluated above the outer join. Now, we wrap it in a PlaceHolderVar and arrange for the actual evaluation to occur below the outer join. When the resulting Var bubbles up through the join, it will be set to NULL if necessary, yielding the correct results. This fixes a planner limitation that's existed since 7.1. In future we might want to use this mechanism to re-introduce some form of Hellerstein's "expensive functions" optimization, ie place the evaluation of an expensive function at the most suitable point in the plan tree.
* Improve the recently-added code for inlining set-returning functions so thatTom Lane2008-10-091-13/+65
| | | | | it can handle functions returning setof record. The case was left undone originally, but it turns out to be simple to fix.
* Implement SQL-standard WITH clauses, including WITH RECURSIVE.Tom Lane2008-10-041-1/+2
| | | | | | | | | | | | | There are some unimplemented aspects: recursive queries must use UNION ALL (should allow UNION too), and we don't have SEARCH or CYCLE clauses. These might or might not get done for 8.4, but even without them it's a pretty useful feature. There are also a couple of small loose ends and definitional quibbles, which I'll send a memo about to pgsql-hackers shortly. But let's land the patch now so we can get on with other development. Yoshiyuki Asaba, with lots of help from Tatsuo Ishii and Tom Lane
* Improve the plan cache invalidation mechanism to make it invalidate plansTom Lane2008-09-091-1/+23
| | | | | | | | | when user-defined functions used in a plan are modified. Also invalidate plans when schemas, operators, or operator classes are modified; but for these cases we just invalidate everything rather than tracking exact dependencies, since these types of objects seldom change in a production database. Tom Lane; loosely based on a patch by Martin Pihlak.
* Extend the parser location infrastructure to include a location field inTom Lane2008-08-281-1/+16
| | | | | | | | | | | | | most node types used in expression trees (both before and after parse analysis). This allows us to place an error cursor in many situations where we formerly could not, because the information wasn't available beyond the very first level of parse analysis. There's a fair amount of work still to be done to persuade individual ereport() calls to actually include an error location, but this gets the initdb-forcing part of the work out of the way; and the situation is already markedly better than before for complaints about unimplementable implicit casts, such as CASE and UNION constructs with incompatible alternative data types. Per my proposal of a few days ago.
* Teach eval_const_expressions() to simplify an ArrayCoerceExpr to a constantTom Lane2008-08-261-1/+36
| | | | | | | | when its input is constant and the element coercion function is immutable (or nonexistent, ie, binary-coercible case). This is an oversight in the 8.3 implementation of ArrayCoerceExpr, and its result is that certain cases involving IN or NOT IN with constants don't get optimized as they should be. Per experimentation with an example from Ow Mun Heng.
* Move exprType(), exprTypmod(), expression_tree_walker(), and related routinesTom Lane2008-08-251-1228/+4
| | | | | | into nodes/nodeFuncs, so as to reduce wanton cross-subsystem #includes inside the backend. There's probably more that should be done along this line, but this is a start anyway.
* Arrange to convert EXISTS subqueries that are equivalent to hashable INTom Lane2008-08-221-3/+23
| | | | | | | | | | | | | | | | | | | | | | | subqueries into the same thing you'd have gotten from IN (except always with unknownEqFalse = true, so as to get the proper semantics for an EXISTS). I believe this fixes the last case within CVS HEAD in which an EXISTS could give worse performance than an equivalent IN subquery. The tricky part of this is that if the upper query probes the EXISTS for only a few rows, the hashing implementation can actually be worse than the default, and therefore we need to make a cost-based decision about which way to use. But at the time when the planner generates plans for subqueries, it doesn't really know how many times the subquery will be executed. The least invasive solution seems to be to generate both plans and postpone the choice until execution. Therefore, in a query that has been optimized this way, EXPLAIN will show two subplans for the EXISTS, of which only one will actually get executed. There is a lot more that could be done based on this infrastructure: in particular it's interesting to consider switching to the hash plan if we start out using the non-hashed plan but find a lot more upper rows going by than we expected. I have therefore left some minor inefficiencies in place, such as initializing both subplans even though we will currently only use one.
* Implement SEMI and ANTI joins in the planner and executor. (Semijoins replaceTom Lane2008-08-141-12/+358
| | | | | | | | | | | | | | the old JOIN_IN code, but antijoins are new functionality.) Teach the planner to convert appropriate EXISTS and NOT EXISTS subqueries into semi and anti joins respectively. Also, LEFT JOINs with suitable upper-level IS NULL filters are recognized as being anti joins. Unify the InClauseInfo and OuterJoinInfo infrastructure into "SpecialJoinInfo". With that change, it becomes possible to associate a SpecialJoinInfo with every join attempt, which permits some cleanup of join selectivity estimation. That needs to be taken much further than this patch does, but the next step is to change the API for oprjoin selectivity functions, which seems like material for a separate patch. So for the moment the output size estimates for semi and especially anti joins are quite bogus.
* Teach the system how to use hashing for UNION. (INTERSECT/EXCEPT will follow,Tom Lane2008-08-071-1/+4
| | | | | | | | | | | but seem like a separate patch since most of the remaining work is on the executor side.) I took the opportunity to push selection of the grouping operators for set operations into the parser where it belongs. Otherwise this is just a small exercise in making prepunion.c consider both alternatives. As with the recent DISTINCT patch, this means we can UNION on datatypes that can hash but not sort, and it means that UNION without ORDER BY is no longer certain to produce sorted output.
* Rearrange the querytree representation of ORDER BY/GROUP BY/DISTINCT itemsTom Lane2008-08-021-80/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | as per my recent proposal: 1. Fold SortClause and GroupClause into a single node type SortGroupClause. We were already relying on them to be struct-equivalent, so using two node tags wasn't accomplishing much except to get in the way of comparing items with equal(). 2. Add an "eqop" field to SortGroupClause to carry the associated equality operator. This is cheap for the parser to get at the same time it's looking up the sort operator, and storing it eliminates the need for repeated not-so-cheap lookups during planning. In future this will also let us represent GROUP/DISTINCT operations on datatypes that have hash opclasses but no btree opclasses (ie, they have equality but no natural sort order). The previous representation simply didn't work for that, since its only indicator of comparison semantics was a sort operator. 3. Add a hasDistinctOn boolean to struct Query to explicitly record whether the distinctClause came from DISTINCT or DISTINCT ON. This allows removing some complicated and not 100% bulletproof code that attempted to figure that out from the distinctClause alone. This patch doesn't in itself create any new capability, but it's necessary infrastructure for future attempts to use hash-based grouping for DISTINCT and UNION/INTERSECT/EXCEPT.
* Add code to eval_const_expressions() to support const-simplification ofTom Lane2008-05-151-1/+66
| | | | | CoerceViaIO nodes. This improves the ability of the planner to deal with cases where the node input is a constant. Per bug #4170.
* Restructure some header files a bit, in particular heapam.h, by removing someAlvaro Herrera2008-05-121-2/+1
| | | | | | | | | | | | unnecessary #include lines in it. Also, move some tuple routine prototypes and macros to htup.h, which allows removal of heapam.h inclusion from some .c files. For this to work, a new header file access/sysattr.h needed to be created, initially containing attribute numbers of system columns, for pg_dump usage. While at it, make contrib ltree, intarray and hstore header files more consistent with our header style.
* Fix an oversight I made in a cleanup patch over a year ago:Tom Lane2008-04-011-3/+9
| | | | | | | | | | eval_const_expressions needs to be passed the PlannerInfo ("root") structure, because in some cases we want it to substitute values for Param nodes. (So "constant" is not so constant as all that ...) This mistake partially disabled optimization of unnamed extended-Query statements in 8.3: in particular the LIKE-to-indexscan optimization would never be applied if the LIKE pattern was passed as a parameter, and constraint exclusion depending on a parameter value didn't work either.
* Simplify and standardize conversions between TEXT datums and ordinary CTom Lane2008-03-251-4/+4
| | | | | | | | | | | | | | | | | | | | strings. This patch introduces four support functions cstring_to_text, cstring_to_text_with_len, text_to_cstring, and text_to_cstring_buffer, and two macros CStringGetTextDatum and TextDatumGetCString. A number of existing macros that provided variants on these themes were removed. Most of the places that need to make such conversions now require just one function or macro call, in place of the multiple notational layers that used to be needed. There are no longer any direct calls of textout or textin, and we got most of the places that were using handmade conversions via memcpy (there may be a few still lurking, though). This commit doesn't make any serious effort to eliminate transient memory leaks caused by detoasting toasted text objects before they reach text_to_cstring. We changed PG_GETARG_TEXT_P to PG_GETARG_TEXT_PP in a few places where it was easy, but much more could be done. Brendan Jurd and Tom Lane
* Arrange to "inline" SQL functions that appear in a query's FROM clause,Tom Lane2008-03-181-22/+306
| | | | | | | are declared to return set, and consist of just a single SELECT. We can replace the FROM-item with a sub-SELECT and then optimize much as if we were dealing with a view. Patch from Richard Rowell, cleaned up by me.
* The original implementation of polymorphic aggregates didn't really get theTom Lane2008-01-111-2/+3
| | | | | | checking of argument compatibility right; although the problem is only exposed with multiple-input aggregates in which some arguments are polymorphic and some are not. Per bug #3852 from Sokolov Yura.
* Update copyrights in source tree to 2008.Bruce Momjian2008-01-011-2/+2
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* Save one syscache lookup when examining volatility or strictness ofTom Lane2007-11-221-12/+23
| | | | | | | | OpExpr and related nodes. We're going to have to set the opfuncid of such nodes eventually (if we haven't already), so we might as well exploit the opportunity to cache the function OID. Buys back some of the extra planner overhead noted by Guillaume Smet, though I still need to fool with equivclass.c to really respond to that.
* pgindent run for 8.3.Bruce Momjian2007-11-151-37/+40
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* Ensure that the result of evaluating a function during constant-expressionTom Lane2007-10-111-3/+14
| | | | | | | simplification gets detoasted before it is incorporated into a Const node. Otherwise, if an immutable function were to return a TOAST pointer (an unlikely case, but it can be made to happen), we would end up with a plan that depends on the continued existence of the out-of-line toast datum.
* Make eval_const_expressions() preserve typmod when simplifying something likeTom Lane2007-09-061-3/+3
| | | | | | | | | | | null::char(3) to a simple Const node. (It already worked for non-null values, but not when we skipped evaluation of a strict coercion function.) This prevents loss of typmod knowledge in situations such as exhibited in bug #3598. Unfortunately there seems no good way to fix that bug in 8.1 and 8.2, because they simply don't carry a typmod for a plain Const node. In passing I made all the other callers of makeNullConst supply "real" typmod values too, though I think it probably doesn't matter anywhere else.
* Implement function-local GUC parameter settings, as per recent discussion.Tom Lane2007-09-031-1/+3
| | | | | | | There are still some loose ends: I didn't do anything about the SET FROM CURRENT idea yet, and it's not real clear whether we are happy with the interaction of SET LOCAL with function-local settings. The documentation is a bit spartan, too.
* Separate parse-analysis for utility commands out of parser/analyze.cTom Lane2007-06-231-10/+4
| | | | | | | | | | | | | | | | | (which now deals only in optimizable statements), and put that code into a new file parser/parse_utilcmd.c. This helps clarify and enforce the design rule that utility statements shouldn't be processed during the regular parse analysis phase; all interpretation of their meaning should happen after they are given to ProcessUtility to execute. (We need this because we don't retain any locks for a utility statement that's in a plan cache, nor have any way to detect that it's stale.) We are also able to simplify the API for parse_analyze() and related routines, because they will now always return exactly one Query structure. In passing, fix bug #3403 concerning trying to add a serial column to an existing temp table (this is largely Heikki's work, but we needed all that restructuring to make it safe).
* Support UPDATE/DELETE WHERE CURRENT OF cursor_name, per SQL standard.Tom Lane2007-06-111-1/+3
| | | | | | | | | Along the way, allow FOR UPDATE in non-WITH-HOLD cursors; there may once have been a reason to disallow that, but it seems to work now, and it's really rather necessary if you want to select a row via a cursor and then update it in a concurrent-safe fashion. Original patch by Arul Shaji, rather heavily editorialized by Tom Lane.
* Downgrade implicit casts to text to be assignment-only, except for the onesTom Lane2007-06-051-1/+67
| | | | | | | | | | | | | | | | | | | | | | | | | from the other string-category types; this eliminates a lot of surprising interpretations that the parser could formerly make when there was no directly applicable operator. Create a general mechanism that supports casts to and from the standard string types (text,varchar,bpchar) for *every* datatype, by invoking the datatype's I/O functions. These new casts are assignment-only in the to-string direction, explicit-only in the other, and therefore should create no surprising behavior. Remove a bunch of thereby-obsoleted datatype-specific casting functions. The "general mechanism" is a new expression node type CoerceViaIO that can actually convert between *any* two datatypes if their external text representations are compatible. This is more general than needed for the immediate feature, but might be useful in plpgsql or other places in future. This commit does nothing about the issue that applying the concatenation operator || to non-text types will now fail, often with strange error messages due to misinterpreting the operator as array concatenation. Since it often (not always) worked before, we should either make it succeed or at least give a more user-friendly error; but details are still under debate. Peter Eisentraut and Tom Lane
* Fix a thinko in my patch of a couple months ago for bug #3116: it did theTom Lane2007-05-011-4/+4
| | | | | | | | | | wrong thing when inlining polymorphic SQL functions, because it was using the function's declared return type where it should have used the actual result type of the current call. In 8.1 and 8.2 this causes obvious failures even if you don't have assertions turned on; in 8.0 and 7.4 it would only be a problem if the inlined expression were used as an input to a function that did run-time type determination on its inputs. Add a regression test, since this is evidently an under-tested area.
* Marginal performance hack: avoid unnecessary work in expression_tree_mutator.Tom Lane2007-04-301-4/+25
| | | | | | We can just palloc, instead of using makeNode, when we are going to overwrite the whole node anyway in the FLATCOPY macro. Also, use FLATCOPY instead of copyObject for common node types Var and Const.
* Modify processing of DECLARE CURSOR and EXPLAIN so that they can resolve theTom Lane2007-04-271-2/+3
| | | | | | | | | | | | | | types of unspecified parameters when submitted via extended query protocol. This worked in 8.2 but I had broken it during plancache changes. DECLARE CURSOR is now treated almost exactly like a plain SELECT through parse analysis, rewrite, and planning; only just before sending to the executor do we divert it away to ProcessUtility. This requires a special-case check in a number of places, but practically all of them were already special-casing SELECT INTO, so it's not too ugly. (Maybe it would be a good idea to merge the two by treating IntoClause as a form of utility statement? Not going to worry about that now, though.) That approach doesn't work for EXPLAIN, however, so for that I punted and used a klugy solution of running parse analysis an extra time if under extended query protocol.
* Support enum data types. Along the way, use macros for the values ofTom Lane2007-04-021-4/+3
| | | | | pg_type.typtype whereever practical. Tom Dunstan, with some kibitzing from Tom Lane.
* Fix array coercion expressions to ensure that the correct volatility isTom Lane2007-03-271-11/+58
| | | | | | | | | seen by code inspecting the expression. The best way to do this seems to be to drop the original representation as a function invocation, and instead make a special expression node type that represents applying the element-type coercion function to each array element. In this way the element function is exposed and will be checked for volatility. Per report from Guillaume Smet.
* Fix up the remaining places where the expression node structure would loseTom Lane2007-03-171-25/+31
| | | | | | | | | | | | | | available information about the typmod of an expression; namely, Const, ArrayRef, ArrayExpr, and EXPR and ARRAY SubLinks. In the ArrayExpr and SubLink cases it wasn't really the data structure's fault, but exprTypmod() being lazy. This seems like a good idea in view of the expected increase in typmod usage from Teodor's work to allow user-defined types to have typmods. In particular this responds to the concerns we had about eliminating the special-purpose hack that exprTypmod() used to have for BPCHAR Consts. We can now tell whether or not such a Const has been cast to a specific length, and report or display properly if so. initdb forced due to changes in stored rules.
* First phase of plan-invalidation project: create a plan cache managementTom Lane2007-03-131-33/+1
| | | | | | | | | | | | | | | | module and teach PREPARE and protocol-level prepared statements to use it. In service of this, rearrange utility-statement processing so that parse analysis does not assume table schemas can't change before execution for utility statements (necessary because we don't attempt to re-acquire locks for utility statements when reusing a stored plan). This requires some refactoring of the ProcessUtility API, but it ends up cleaner anyway, for instance we can get rid of the QueryContext global. Still to do: fix up SPI and related code to use the plan cache; I'm tempted to try to make SQL functions use it too. Also, there are at least some aspects of system state that we want to ensure remain the same during a replan as in the original processing; search_path certainly ought to behave that way for instance, and perhaps there are others.