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is unique and is not referenced above the join. In this case the inner side doesn't affect the query result and can be thrown away entirely. Although perhaps nobody would ever write such a thing by hand, it's a reasonably common case in machine-generated SQL. The current implementation only recognizes the case where the inner side is a simple relation with a unique index matching the query conditions. This is enough for the use-cases that have been shown so far, but we might want to try to handle other cases later. Robert Haas, somewhat rewritten by Tom
106 lines
3.6 KiB
C
106 lines
3.6 KiB
C
/*-------------------------------------------------------------------------
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*
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* pathnode.h
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* prototypes for pathnode.c, relnode.c.
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*
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*
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* Portions Copyright (c) 1996-2009, 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/pathnode.h,v 1.81 2009/09/17 20:49:29 tgl Exp $
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*
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*-------------------------------------------------------------------------
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*/
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#ifndef PATHNODE_H
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#define PATHNODE_H
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#include "nodes/relation.h"
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/*
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* prototypes for pathnode.c
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*/
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extern int compare_path_costs(Path *path1, Path *path2,
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CostSelector criterion);
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extern int compare_fractional_path_costs(Path *path1, Path *path2,
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double fraction);
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extern void set_cheapest(RelOptInfo *parent_rel);
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extern void add_path(RelOptInfo *parent_rel, Path *new_path);
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extern Path *create_seqscan_path(PlannerInfo *root, RelOptInfo *rel);
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extern IndexPath *create_index_path(PlannerInfo *root,
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IndexOptInfo *index,
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List *clause_groups,
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List *pathkeys,
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ScanDirection indexscandir,
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RelOptInfo *outer_rel);
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extern BitmapHeapPath *create_bitmap_heap_path(PlannerInfo *root,
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RelOptInfo *rel,
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Path *bitmapqual,
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RelOptInfo *outer_rel);
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extern BitmapAndPath *create_bitmap_and_path(PlannerInfo *root,
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RelOptInfo *rel,
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List *bitmapquals);
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extern BitmapOrPath *create_bitmap_or_path(PlannerInfo *root,
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RelOptInfo *rel,
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List *bitmapquals);
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extern TidPath *create_tidscan_path(PlannerInfo *root, RelOptInfo *rel,
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List *tidquals);
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extern AppendPath *create_append_path(RelOptInfo *rel, List *subpaths);
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extern ResultPath *create_result_path(List *quals);
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extern MaterialPath *create_material_path(RelOptInfo *rel, Path *subpath);
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extern UniquePath *create_unique_path(PlannerInfo *root, RelOptInfo *rel,
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Path *subpath, SpecialJoinInfo *sjinfo);
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extern NoOpPath *create_noop_path(PlannerInfo *root, RelOptInfo *rel,
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Path *subpath);
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extern Path *create_subqueryscan_path(RelOptInfo *rel, List *pathkeys);
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extern Path *create_functionscan_path(PlannerInfo *root, RelOptInfo *rel);
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extern Path *create_valuesscan_path(PlannerInfo *root, RelOptInfo *rel);
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extern Path *create_ctescan_path(PlannerInfo *root, RelOptInfo *rel);
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extern Path *create_worktablescan_path(PlannerInfo *root, RelOptInfo *rel);
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extern NestPath *create_nestloop_path(PlannerInfo *root,
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RelOptInfo *joinrel,
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JoinType jointype,
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SpecialJoinInfo *sjinfo,
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Path *outer_path,
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Path *inner_path,
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List *restrict_clauses,
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List *pathkeys);
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extern MergePath *create_mergejoin_path(PlannerInfo *root,
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RelOptInfo *joinrel,
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JoinType jointype,
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SpecialJoinInfo *sjinfo,
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Path *outer_path,
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Path *inner_path,
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List *restrict_clauses,
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List *pathkeys,
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List *mergeclauses,
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List *outersortkeys,
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List *innersortkeys);
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extern HashPath *create_hashjoin_path(PlannerInfo *root,
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RelOptInfo *joinrel,
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JoinType jointype,
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SpecialJoinInfo *sjinfo,
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Path *outer_path,
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Path *inner_path,
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List *restrict_clauses,
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List *hashclauses);
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/*
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* prototypes for relnode.c
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*/
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extern RelOptInfo *build_simple_rel(PlannerInfo *root, int relid,
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RelOptKind reloptkind);
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extern RelOptInfo *find_base_rel(PlannerInfo *root, int relid);
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extern RelOptInfo *find_join_rel(PlannerInfo *root, Relids relids);
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extern RelOptInfo *build_join_rel(PlannerInfo *root,
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Relids joinrelids,
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RelOptInfo *outer_rel,
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RelOptInfo *inner_rel,
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SpecialJoinInfo *sjinfo,
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List **restrictlist_ptr);
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#endif /* PATHNODE_H */
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