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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.
28 lines
770 B
C
28 lines
770 B
C
/*-------------------------------------------------------------------------
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*
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* joininfo.h
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* prototypes for joininfo.c.
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*
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*
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* Portions Copyright (c) 1996-2007, PostgreSQL Global Development Group
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* Portions Copyright (c) 1994, Regents of the University of California
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*
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* $PostgreSQL: pgsql/src/include/optimizer/joininfo.h,v 1.34 2007/01/20 20:45:40 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef JOININFO_H
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#define JOININFO_H
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#include "nodes/relation.h"
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extern bool have_relevant_joinclause(PlannerInfo *root,
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RelOptInfo *rel1, RelOptInfo *rel2);
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extern void add_join_clause_to_rels(PlannerInfo *root,
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RestrictInfo *restrictinfo,
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Relids join_relids);
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#endif /* JOININFO_H */
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