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Refactor planner's pathkeys data structure to create a separate, explicit

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representation of equivalence classes of variables.  This is an extensive
rewrite, but it brings a number of benefits:
* planner no longer fails in the presence of "incomplete" operator families
that don't offer operators for every possible combination of datatypes.
* avoid generating and then discarding redundant equality clauses.
* remove bogus assumption that derived equalities always use operators
named "=".
* mergejoins can work with a variety of sort orders (e.g., descending) now,
instead of tying each mergejoinable operator to exactly one sort order.
* better recognition of redundant sort columns.
* can make use of equalities appearing underneath an outer join.
This commit is contained in:
Tom Lane
2007-01-20 20:45:41 +00:00
parent 2b7334d487
commit f41803bb39
35 changed files with 3882 additions and 2719 deletions
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5
src/include/utils/lsyscache.h
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@@ -6,7 +6,7 @@
* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
* $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.112 2007/01/10 18:06:05 tgl Exp $
* $PostgreSQL: pgsql/src/include/utils/lsyscache.h,v 1.113 2007/01/20 20:45:41 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@@ -35,12 +35,11 @@ extern void get_op_opfamily_properties(Oid opno, Oid opfamily,
bool *recheck);
extern Oid get_opfamily_member(Oid opfamily, Oid lefttype, Oid righttype,
int16 strategy);
extern bool get_op_mergejoin_info(Oid eq_op, Oid *left_sortop,
Oid *right_sortop, Oid *opfamily);
extern bool get_compare_function_for_ordering_op(Oid opno,
Oid *cmpfunc, bool *reverse);
extern Oid get_equality_op_for_ordering_op(Oid opno);
extern Oid get_ordering_op_for_equality_op(Oid opno, bool use_lhs_type);
extern List *get_mergejoin_opfamilies(Oid opno);
extern Oid get_compatible_hash_operator(Oid opno, bool use_lhs_type);
extern Oid get_op_hash_function(Oid opno);
extern void get_op_btree_interpretation(Oid opno,