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https://github.com/postgres/postgres.git
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Robert Haas
45be99f8cd
The core innovation of this patch is the introduction of the concept of a partial path; that is, a path which if executed in parallel will generate a subset of the output rows in each process. Gathering a partial path produces an ordinary (complete) path. This allows us to generate paths for parallel joins by joining a partial path for one side (which at the baserel level is currently always a Partial Seq Scan) to an ordinary path on the other side. This is subject to various restrictions at present, especially that this strategy seems unlikely to be sensible for merge joins, so only nested loops and hash joins paths are generated. This also allows an Append node to be pushed below a Gather node in the case of a partitioned table. Testing revealed that early versions of this patch made poor decisions in some cases, which turned out to be caused by the fact that the original cost model for Parallel Seq Scan wasn't very good. So this patch tries to make some modest improvements in that area. There is much more to be done in the area of generating good parallel plans in all cases, but this seems like a useful step forward. Patch by me, reviewed by Dilip Kumar and Amit Kapila.
176 lines
6.4 KiB
C
176 lines
6.4 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) 1996-2016, 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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* src/include/optimizer/pathnode.h
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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 bool add_path_precheck(RelOptInfo *parent_rel,
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Cost startup_cost, Cost total_cost,
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List *pathkeys, Relids required_outer);
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extern void add_partial_path(RelOptInfo *parent_rel, Path *new_path);
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extern bool add_partial_path_precheck(RelOptInfo *parent_rel,
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Cost total_cost, List *pathkeys);
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extern Path *create_seqscan_path(PlannerInfo *root, RelOptInfo *rel,
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Relids required_outer, int parallel_degree);
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extern Path *create_samplescan_path(PlannerInfo *root, RelOptInfo *rel,
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Relids required_outer);
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extern IndexPath *create_index_path(PlannerInfo *root,
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IndexOptInfo *index,
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List *indexclauses,
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List *indexclausecols,
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List *indexorderbys,
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List *indexorderbycols,
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List *pathkeys,
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ScanDirection indexscandir,
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bool indexonly,
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Relids required_outer,
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double loop_count);
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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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Relids required_outer,
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double loop_count);
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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, Relids required_outer);
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extern AppendPath *create_append_path(RelOptInfo *rel, List *subpaths,
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Relids required_outer, int parallel_degree);
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extern MergeAppendPath *create_merge_append_path(PlannerInfo *root,
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RelOptInfo *rel,
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List *subpaths,
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List *pathkeys,
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Relids required_outer);
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extern ResultPath *create_result_path(RelOptInfo *rel, 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 GatherPath *create_gather_path(PlannerInfo *root,
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RelOptInfo *rel, Path *subpath, Relids required_outer);
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extern Path *create_subqueryscan_path(PlannerInfo *root, RelOptInfo *rel,
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List *pathkeys, Relids required_outer);
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extern Path *create_functionscan_path(PlannerInfo *root, RelOptInfo *rel,
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List *pathkeys, Relids required_outer);
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extern Path *create_valuesscan_path(PlannerInfo *root, RelOptInfo *rel,
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Relids required_outer);
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extern Path *create_ctescan_path(PlannerInfo *root, RelOptInfo *rel,
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Relids required_outer);
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extern Path *create_worktablescan_path(PlannerInfo *root, RelOptInfo *rel,
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Relids required_outer);
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extern ForeignPath *create_foreignscan_path(PlannerInfo *root, RelOptInfo *rel,
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double rows, Cost startup_cost, Cost total_cost,
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List *pathkeys,
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Relids required_outer,
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Path *fdw_outerpath,
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List *fdw_private);
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extern Relids calc_nestloop_required_outer(Path *outer_path, Path *inner_path);
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extern Relids calc_non_nestloop_required_outer(Path *outer_path, Path *inner_path);
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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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JoinCostWorkspace *workspace,
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SpecialJoinInfo *sjinfo,
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SemiAntiJoinFactors *semifactors,
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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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Relids required_outer);
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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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JoinCostWorkspace *workspace,
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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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Relids required_outer,
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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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JoinCostWorkspace *workspace,
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SpecialJoinInfo *sjinfo,
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SemiAntiJoinFactors *semifactors,
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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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Relids required_outer,
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List *hashclauses);
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extern Path *reparameterize_path(PlannerInfo *root, Path *path,
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Relids required_outer,
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double loop_count);
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/*
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* prototypes for relnode.c
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*/
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extern void setup_simple_rel_arrays(PlannerInfo *root);
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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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extern Relids min_join_parameterization(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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extern RelOptInfo *build_empty_join_rel(PlannerInfo *root);
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extern AppendRelInfo *find_childrel_appendrelinfo(PlannerInfo *root,
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RelOptInfo *rel);
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extern RelOptInfo *find_childrel_top_parent(PlannerInfo *root, RelOptInfo *rel);
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extern Relids find_childrel_parents(PlannerInfo *root, RelOptInfo *rel);
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extern ParamPathInfo *get_baserel_parampathinfo(PlannerInfo *root,
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RelOptInfo *baserel,
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Relids required_outer);
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extern ParamPathInfo *get_joinrel_parampathinfo(PlannerInfo *root,
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RelOptInfo *joinrel,
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Path *outer_path,
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Path *inner_path,
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SpecialJoinInfo *sjinfo,
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Relids required_outer,
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List **restrict_clauses);
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extern ParamPathInfo *get_appendrel_parampathinfo(RelOptInfo *appendrel,
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Relids required_outer);
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#endif /* PATHNODE_H */
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