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Make sequential scans parallel-aware.

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In addition, this path fills in a number of missing bits and pieces in
the parallel infrastructure.  Paths and plans now have a parallel_aware
flag indicating whether whatever parallel-aware logic they have should
be engaged.  It is believed that we will need this flag for a number of
path/plan types, not just sequential scans, which is why the flag is
generic rather than part of the SeqScan structures specifically.
Also, execParallel.c now gives parallel nodes a chance to initialize
their PlanState nodes from the DSM during parallel worker startup.

Amit Kapila, with a fair amount of adjustment by me.  Review of previous
patch versions by Haribabu Kommi and others.
This commit is contained in:
Robert Haas
2015-11-11 08:57:52 -05:00
parent f764ecd81b
commit f0661c4e8c
18 changed files with 254 additions and 73 deletions
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29
src/backend/optimizer/util/pathnode.c
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@ -696,7 +696,8 @@ add_path_precheck(RelOptInfo *parent_rel,
* pathnode.
*/
Path *
create_seqscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
create_seqscan_path(PlannerInfo *root, RelOptInfo *rel,
Relids required_outer, int nworkers)
{
Path *pathnode = makeNode(Path);
@ -704,9 +705,10 @@ create_seqscan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
pathnode->parent = rel;
pathnode->param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->parallel_aware = nworkers > 0 ? true : false;
pathnode->pathkeys = NIL; /* seqscan has unordered result */
cost_seqscan(pathnode, root, rel, pathnode->param_info);
cost_seqscan(pathnode, root, rel, pathnode->param_info, nworkers);
return pathnode;
}
@ -724,6 +726,7 @@ create_samplescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer
pathnode->parent = rel;
pathnode->param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->parallel_aware = false;
pathnode->pathkeys = NIL; /* samplescan has unordered result */
cost_samplescan(pathnode, root, rel, pathnode->param_info);
@ -777,6 +780,7 @@ create_index_path(PlannerInfo *root,
pathnode->path.parent = rel;
pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = pathkeys;
/* Convert clauses to indexquals the executor can handle */
@ -822,6 +826,7 @@ create_bitmap_heap_path(PlannerInfo *root,
pathnode->path.parent = rel;
pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = NIL; /* always unordered */
pathnode->bitmapqual = bitmapqual;
@ -847,6 +852,7 @@ create_bitmap_and_path(PlannerInfo *root,
pathnode->path.pathtype = T_BitmapAnd;
pathnode->path.parent = rel;
pathnode->path.param_info = NULL; /* not used in bitmap trees */
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = NIL; /* always unordered */
pathnode->bitmapquals = bitmapquals;
@ -871,6 +877,7 @@ create_bitmap_or_path(PlannerInfo *root,
pathnode->path.pathtype = T_BitmapOr;
pathnode->path.parent = rel;
pathnode->path.param_info = NULL; /* not used in bitmap trees */
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = NIL; /* always unordered */
pathnode->bitmapquals = bitmapquals;
@ -895,6 +902,7 @@ create_tidscan_path(PlannerInfo *root, RelOptInfo *rel, List *tidquals,
pathnode->path.parent = rel;
pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = NIL; /* always unordered */
pathnode->tidquals = tidquals;
@ -922,6 +930,7 @@ create_append_path(RelOptInfo *rel, List *subpaths, Relids required_outer)
pathnode->path.parent = rel;
pathnode->path.param_info = get_appendrel_parampathinfo(rel,
required_outer);
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = NIL; /* result is always considered
* unsorted */
pathnode->subpaths = subpaths;
@ -975,6 +984,7 @@ create_merge_append_path(PlannerInfo *root,
pathnode->path.parent = rel;
pathnode->path.param_info = get_appendrel_parampathinfo(rel,
required_outer);
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = pathkeys;
pathnode->subpaths = subpaths;
@ -1049,6 +1059,7 @@ create_result_path(List *quals)
pathnode->path.pathtype = T_Result;
pathnode->path.parent = NULL;
pathnode->path.param_info = NULL; /* there are no other rels... */
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = NIL;
pathnode->quals = quals;
@ -1082,6 +1093,7 @@ create_material_path(RelOptInfo *rel, Path *subpath)
pathnode->path.pathtype = T_Material;
pathnode->path.parent = rel;
pathnode->path.param_info = subpath->param_info;
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = subpath->pathkeys;
pathnode->subpath = subpath;
@ -1142,6 +1154,7 @@ create_unique_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
pathnode->path.pathtype = T_Unique;
pathnode->path.parent = rel;
pathnode->path.param_info = subpath->param_info;
pathnode->path.parallel_aware = false;
/*
* Assume the output is unsorted, since we don't necessarily have pathkeys
@ -1323,6 +1336,7 @@ create_gather_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
pathnode->path.parent = rel;
pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = NIL; /* Gather has unordered result */
pathnode->subpath = subpath;
@ -1378,6 +1392,7 @@ create_subqueryscan_path(PlannerInfo *root, RelOptInfo *rel,
pathnode->parent = rel;
pathnode->param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->parallel_aware = false;
pathnode->pathkeys = pathkeys;
cost_subqueryscan(pathnode, root, rel, pathnode->param_info);
@ -1400,6 +1415,7 @@ create_functionscan_path(PlannerInfo *root, RelOptInfo *rel,
pathnode->parent = rel;
pathnode->param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->parallel_aware = false;
pathnode->pathkeys = pathkeys;
cost_functionscan(pathnode, root, rel, pathnode->param_info);
@ -1422,6 +1438,7 @@ create_valuesscan_path(PlannerInfo *root, RelOptInfo *rel,
pathnode->parent = rel;
pathnode->param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->parallel_aware = false;
pathnode->pathkeys = NIL; /* result is always unordered */
cost_valuesscan(pathnode, root, rel, pathnode->param_info);
@ -1443,6 +1460,7 @@ create_ctescan_path(PlannerInfo *root, RelOptInfo *rel, Relids required_outer)
pathnode->parent = rel;
pathnode->param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->parallel_aware = false;
pathnode->pathkeys = NIL; /* XXX for now, result is always unordered */
cost_ctescan(pathnode, root, rel, pathnode->param_info);
@ -1465,6 +1483,7 @@ create_worktablescan_path(PlannerInfo *root, RelOptInfo *rel,
pathnode->parent = rel;
pathnode->param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->parallel_aware = false;
pathnode->pathkeys = NIL; /* result is always unordered */
/* Cost is the same as for a regular CTE scan */
@ -1496,6 +1515,7 @@ create_foreignscan_path(PlannerInfo *root, RelOptInfo *rel,
pathnode->path.parent = rel;
pathnode->path.param_info = get_baserel_parampathinfo(root, rel,
required_outer);
pathnode->path.parallel_aware = false;
pathnode->path.rows = rows;
pathnode->path.startup_cost = startup_cost;
pathnode->path.total_cost = total_cost;
@ -1630,6 +1650,7 @@ create_nestloop_path(PlannerInfo *root,
sjinfo,
required_outer,
&restrict_clauses);
pathnode->path.parallel_aware = false;
pathnode->path.pathkeys = pathkeys;
pathnode->jointype = jointype;
pathnode->outerjoinpath = outer_path;
@ -1687,6 +1708,7 @@ create_mergejoin_path(PlannerInfo *root,
sjinfo,
required_outer,
&restrict_clauses);
pathnode->jpath.path.parallel_aware = false;
pathnode->jpath.path.pathkeys = pathkeys;
pathnode->jpath.jointype = jointype;
pathnode->jpath.outerjoinpath = outer_path;
@ -1743,6 +1765,7 @@ create_hashjoin_path(PlannerInfo *root,
sjinfo,
required_outer,
&restrict_clauses);
pathnode->jpath.path.parallel_aware = false;
/*
* A hashjoin never has pathkeys, since its output ordering is
@ -1798,7 +1821,7 @@ reparameterize_path(PlannerInfo *root, Path *path,
switch (path->pathtype)
{
case T_SeqScan:
return create_seqscan_path(root, rel, required_outer);
return create_seqscan_path(root, rel, required_outer, 0);
case T_SampleScan:
return (Path *) create_samplescan_path(root, rel, required_outer);
case T_IndexScan: