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2004-01-19Recognize that IN subqueries return already-unique results if they useTom Lane
UNION/INTERSECT/EXCEPT (without ALL). This adds on to the previous optimization for subqueries using DISTINCT.
2004-01-12Preserve AND/OR flatness during eval_const_expressions(). This seems aTom Lane
useful improvement in any case, and it keeps the new logic for restrictinfo structures happy. Per report from Kris Jurka.
2004-01-10Improve has_nullable_targetlist() to allow strict functions of simpleTom Lane
variables, not just simple variables. This was foreseen in the original coding of this routine, but not implemented until now. Responds to performance gripe from Laurent Perez.
2004-01-07More janitorial work: remove the explicit casting of NULL literals to aNeil Conway
pointer type when it is not necessary to do so. For future reference, casting NULL to a pointer type is only necessary when (a) invoking a function AND either (b) the function has no prototype OR (c) the function is a varargs function.
2004-01-05Adjust indexscan planning logic to keep RestrictInfo nodes associatedTom Lane
with index qual clauses in the Path representation. This saves a little work during createplan and (probably more importantly) allows reuse of cached selectivity estimates during indexscan planning. Also fix latent bug: wrong plan would have been generated for a 'special operator' used in a nestloop-inner-indexscan join qual, because the special operator would not have gotten into the list of quals to recheck. This bug is only latent because at present the special-operator code could never trigger on a join qual, but sooner or later someone will want to do it.
2004-01-05Improve UniquePath logic to detect the case where the input is alreadyTom Lane
known unique (eg, it is a SELECT DISTINCT ... subquery), and not do a redundant unique-ification step.
2004-01-05Add the ability to extract OR indexscan conditions from OR-of-ANDTom Lane
join conditions in which each OR subclause includes a constraint on the same relation. This implements the other useful side-effect of conversion to CNF format, without its unpleasant side-effects. As per pghackers discussion of a few weeks ago.
2004-01-04Merge restrictlist_selectivity into clauselist_selectivity byTom Lane
teaching the latter to accept either RestrictInfo nodes or bare clause expressions; and cache the selectivity result in the RestrictInfo node when possible. This extends the caching behavior of approx_selectivity to many more contexts, and should reduce duplicate selectivity calculations.
2004-01-04Rewrite OR indexscan processing to be more flexible. We can now for theTom Lane
first time generate an OR indexscan for a two-column index when the WHERE condition is like 'col1 = foo AND (col2 = bar OR col2 = baz)' --- before, the OR had to be on the first column of the index or we'd not notice the possibility of using it. Some progress towards extracting OR indexscans from subclauses of an OR that references multiple relations, too, although this code is #ifdef'd out because it needs more work.
2003-12-30Adjust the definition of RestrictInfo's left_relids and right_relidsTom Lane
fields: now they are valid whenever the clause is a binary opclause, not only when it is a potential join clause (there is a new boolean field canjoin to signal the latter condition). This lets us avoid recomputing the relid sets over and over while examining indexes. Still more work to do to make this as useful as it could be, because there are places that could use the info but don't have access to the RestrictInfo node.
2003-12-28Clean up the usage of canonicalize_qual(): in particular, be consistentTom Lane
about whether it is applied before or after eval_const_expressions(). I believe there were some corner cases where the system would fail to recognize that a partial index is applicable because of the previous inconsistency. Store normal rather than 'implicit AND' representations of constraints and index predicates in the catalogs. initdb forced due to representation change of constraints/predicates.
2003-12-09query_tree_mutator should copy RangeTblEntry nodes even when it's notTom Lane
planning to modify them itself. Otherwise we end up with shared RTE substructure, which breaks inheritance_planner because the rte->inh flag needs to be independent in each copied subquery. Per bug report from Chris Piker.
2003-12-08Whole-row references were broken for subqueries and functions, becauseTom Lane
attr_needed/attr_widths optimization failed to allow for Vars with attno zero in this case. Per report from Tatsuo Ishii.
2003-11-29$Header: -> $PostgreSQL Changes ...PostgreSQL Daemon
2003-11-12Cross-data-type comparisons are now indexable by btrees, pursuant to myTom Lane
pghackers proposal of 8-Nov. All the existing cross-type comparison operators (int2/int4/int8 and float4/float8) have appropriate support. The original proposal of storing the right-hand-side datatype as part of the primary key for pg_amop and pg_amproc got modified a bit in the event; it is easier to store zero as the 'default' case and only store a nonzero when the operator is actually cross-type. Along the way, remove the long-since-defunct bigbox_ops operator class.
2003-11-09Add operator strategy and comparison-value datatype fields to ScanKey.Tom Lane
Remove the 'strategy map' code, which was a large amount of mechanism that no longer had any use except reverse-mapping from procedure OID to strategy number. Passing the strategy number to the index AM in the first place is simpler and faster. This is a preliminary step in planned support for cross-datatype index operations. I'm committing it now since the ScanKeyEntryInitialize() API change touches quite a lot of files, and I want to commit those changes before the tree drifts under me.
2003-10-29Give a useful error message if a RangeVar is encountered in an expression.Tom Lane
Per example from Ian Barwick, 28-Oct-03.
2003-08-17Fix ARRAY[] construct so that in multidimensional case, elements canTom Lane
be anything yielding an array of the proper kind, not only sub-ARRAY[] constructs; do subscript checking at runtime not parse time. Also, adjust array_cat to make array || array comply with the SQL99 spec. Joe Conway
2003-08-08Another pgindent run with updated typedefs.Bruce Momjian
2003-08-04Update copyrights to 2003.Bruce Momjian
2003-08-04pgindent run.Bruce Momjian
2003-08-03Tighten inline_function's test for overly complex parameters. ThisTom Lane
should catch most situations where repeated inlining blows up the expression complexity unreasonably, as in Joe Conway's recent example.
2003-07-28Add error stack traceback support for SQL-language functions.Tom Lane
2003-07-25Error message editing in backend/optimizer, backend/rewrite.Tom Lane
2003-07-14Make cost estimates for SubqueryScan more realistic: charge cpu_tuple_costTom Lane
for each row processed, and don't forget the evaluation cost of any restriction clauses attached to the node. Per discussion with Greg Stark.
2003-07-03Do honest transformation and preprocessing of LIMIT/OFFSET clauses,Tom Lane
instead of the former kluge whereby gram.y emitted already-transformed expressions. This is needed so that Params appearing in these clauses actually work correctly. I suppose some might claim that the side effect of 'SELECT ... LIMIT 2+2' working is a new feature, but I say this is a bug fix.
2003-07-03Code review for UPDATE tab SET col = DEFAULT patch ... whack it aroundTom Lane
so it has some chance of working in rules ...
2003-07-01Dept. of second thoughts: supporting inlining of polymorphic SQL functionsTom Lane
takes only a few more lines of code than preventing it, so might as well support it.
2003-07-01SQL functions can have arguments and results declared ANYARRAY orTom Lane
ANYELEMENT. The effect is to postpone typechecking of the function body until runtime. Documentation is still lacking. Original patch by Joe Conway, modified to postpone type checking by Tom Lane.
2003-06-29Restructure building of join relation targetlists so that a join planTom Lane
node emits only those vars that are actually needed above it in the plan tree. (There were comments in the code suggesting that this was done at some point in the dim past, but for a long time we have just made join nodes emit everything that either input emitted.) Aside from being marginally more efficient, this fixes the problem noted by Peter Eisentraut where a join above an IN-implemented-as-join might fail, because the subplan targetlist constructed in the latter case didn't meet the expectation of including everything. Along the way, fix some places that were O(N^2) in the targetlist length. This is not all the trouble spots for wide queries by any means, but it's a step forward.
2003-06-29Support expressions of the form 'scalar op ANY (array)' andTom Lane
'scalar op ALL (array)', where the operator is applied between the lefthand scalar and each element of the array. The operator must yield boolean; the result of the construct is the OR or AND of the per-element results, respectively. Original coding by Joe Conway, after an idea of Peter's. Rewritten by Tom to keep the implementation strictly separate from subqueries.
2003-06-25Back out array mega-patch.Bruce Momjian
Joe Conway
2003-06-24Array mega-patch.Bruce Momjian
Joe Conway
2003-06-15Adjust nestloop-with-inner-indexscan plan generation so that we catchTom Lane
some cases of redundant clauses that were formerly not caught. We have to special-case this because the clauses involved never get attached to the same join restrictlist and so the existing logic does not notice that they are redundant.
2003-06-06Implement outer-level aggregates to conform to the SQL spec, withTom Lane
extensions to support our historical behavior. An aggregate belongs to the closest query level of any of the variables in its argument, or the current query level if there are no variables (e.g., COUNT(*)). The implementation involves adding an agglevelsup field to Aggref, and treating outer aggregates like outer variables at planning time.
2003-05-28Fix some planner performance problems with large WHERE clauses, byTom Lane
introducing new 'FastList' list-construction subroutines to use in hot spots. This avoids the O(N^2) behavior of repeated lappend's by keeping a tail pointer, while not changing behavior by reversing list order as the lcons() method would do.
2003-05-28Replace functional-index facility with expressional indexes. Any columnTom Lane
of an index can now be a computed expression instead of a simple variable. Restrictions on expressions are the same as for predicates (only immutable functions, no sub-selects). This fixes problems recently introduced with inlining SQL functions, because the inlining transformation is applied to both expression trees so the planner can still match them up. Along the way, improve efficiency of handling index predicates (both predicates and index expressions are now cached by the relcache) and fix 7.3 oversight that didn't record dependencies of predicate expressions.
2003-05-26Cause CHAR(n) to TEXT or VARCHAR conversion to automatically strip trailingTom Lane
blanks, in hopes of reducing the surprise factor for newbies. Remove redundant operators for VARCHAR (it depends wholly on TEXT operations now). Clean up resolution of ambiguous operators/functions to avoid surprising choices for domains: domains are treated as equivalent to their base types and binary-coercibility is no longer considered a preference item when choosing among multiple operators/functions. IsBinaryCoercible now correctly reflects the notion that you need *only* relabel the type to get from type A to type B: that is, a domain is binary-coercible to its base type, but not vice versa. Various marginal cleanup, including merging the essentially duplicate resolution code in parse_func.c and parse_oper.c. Improve opr_sanity regression test to understand about binary compatibility (using pg_cast), and fix a couple of small errors in the catalogs revealed thereby. Restructure "special operator" handling to fetch operators via index opclasses rather than hardwiring assumptions about names (cleans up the pattern_ops stuff a little).
2003-05-12Apply fixes for problems with dropped columns whose types have also beenTom Lane
dropped. The simplest fix for INSERT/UPDATE cases turns out to be for preptlist.c to insert NULLs of a known-good type (I used INT4) rather than making them match the deleted column's type. Since the representation of NULL is actually datatype-independent, this should work fine. I also re-reverted the patch to disable the use_physical_tlist optimization in the presence of dropped columns. It still doesn't look worth the trouble to be smarter, if there are no other bugs to fix. Added a regression test to catch future problems in this area.
2003-05-11Revert previous change --- turns out the underlying problem affectsTom Lane
more cases than I thought, so ExecTypeFromTL() will have to be fixed anyway.
2003-05-11Disable the recently-added use_physical_tlist optimization in casesTom Lane
where the table contains dropped columns. If the columns are dropped, then their types may be gone as well, which causes ExecTypeFromTL() to fail if the dropped columns appear in a plan node's tlist. This could be worked around but I don't think the optimization is valuable enough to be worth the trouble.
2003-05-06Implement feature of new FE/BE protocol whereby RowDescription identifiesTom Lane
the column by table OID and column number, if it's a simple column reference. Along the way, get rid of reskey/reskeyop fields in Resdoms. Turns out that representation was not convenient for either the planner or the executor; we can make the planner deliver exactly what the executor wants with no more effort. initdb forced due to change in stored rule representation.
2003-04-29Infrastructure for deducing Param types from context, in the same wayTom Lane
that the types of untyped string-literal constants are deduced (ie, when coerce_type is applied to 'em, that's what the type must be). Remove the ancient hack of storing the input Param-types array as a global variable, and put the info into ParseState instead. This touches a lot of files because of adjustment of routine parameter lists, but it's really not a large patch. Note: PREPARE statement still insists on exact specification of parameter types, but that could easily be relaxed now, if we wanted to do so.
2003-04-27Put back encoding-conversion step in processing of incoming queries;Tom Lane
I had inadvertently omitted it while rearranging things to support length-counted incoming messages. Also, change the parser's API back to accepting a 'char *' query string instead of 'StringInfo', as the latter wasn't buying us anything except overhead. (I think when I put it in I had some notion of making the parser API 8-bit-clean, but seeing that flex depends on null-terminated input, that's not really ever gonna happen.)
2003-04-08First phase of work on array improvements. ARRAY[x,y,z] constructorTom Lane
expressions, ARRAY(sub-SELECT) expressions, some array functions. Polymorphic functions using ANYARRAY/ANYELEMENT argument and return types. Some regression tests in place, documentation is lacking. Joe Conway, with some kibitzing from Tom Lane.
2003-03-22Adjust subquery qual pushdown rules to be more forgiving: if a qualTom Lane
refers to a non-DISTINCT output column of a DISTINCT ON subquery, or if it refers to a function-returning-set, we cannot push it down. But the old implementation refused to push down *any* quals if the subquery had any such 'dangerous' outputs. Now we just look at the output columns actually referenced by each qual expression. More code than before, but probably no slower since we don't make unnecessary checks.
2003-03-14Make eval_const_expressions simplify FieldSelect from a whole-row VarTom Lane
into an ordinary one-field Var. Per example from Chris Mungall.
2003-03-10Restructure parsetree representation of DECLARE CURSOR: now it's aTom Lane
utility statement (DeclareCursorStmt) with a SELECT query dangling from it, rather than a SELECT query with a few unusual fields in it. Add code to determine whether a planned query can safely be run backwards. If DECLARE CURSOR specifies SCROLL, ensure that the plan can be run backwards by adding a Materialize plan node if it can't. Without SCROLL, you get an error if you try to fetch backwards from a cursor that can't handle it. (There is still some discussion about what the exact behavior should be, but this is necessary infrastructure in any case.) Along the way, make EXPLAIN DECLARE CURSOR work.
2003-02-16COALESCE() and NULLIF() are now first-class expressions, not macrosTom Lane
that turn into CASE expressions. They evaluate their arguments at most once. Patch by Kris Jurka, review and (very light) editorializing by me.
2003-02-15Teach planner how to propagate pathkeys from sub-SELECTs in FROM up toTom Lane
the outer query. (The implementation is a bit klugy, but it would take nontrivial restructuring to make it nicer, which this is probably not worth.) This avoids unnecessary sort steps in examples like SELECT foo,count(*) FROM (SELECT ... ORDER BY foo,bar) sub GROUP BY foo which means there is now a reasonable technique for controlling the order of inputs to custom aggregates, even in the grouping case.