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Rearrange make_partitionedrel_pruneinfo to avoid work when we can't prune.

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Postpone most of the effort of constructing PartitionedRelPruneInfos
until after we have found out whether run-time pruning is needed at all.
This costs very little duplicated effort (basically just an extra
find_base_rel() call per partition) and saves quite a bit when we
can't do run-time pruning.

Also, merge the first loop (for building relid_subpart_map) into
the second loop, since we don't need the map to be valid during
that loop.

Amit Langote

Discussion: https://postgr.es/m/9d7c5112-cb99-6a47-d3be-cf1ee6862a1d@lab.ntt.co.jp
This commit is contained in:
Tom Lane 2019-03-22 14:56:05 -04:00
parent 09963cedce
commit 734308a220
1 changed files with 68 additions and 40 deletions
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108
src/backend/partitioning/partprune.c
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@ -326,46 +326,43 @@ make_partitionedrel_pruneinfo(PlannerInfo *root, RelOptInfo *parentrel,
int i;
/*
* Construct a temporary array to map from planner relids to index of the
* partitioned_rel. For convenience, we use 1-based indexes here, so that
* zero can represent an un-filled array entry.
* Examine each partitioned rel, constructing a temporary array to map
* from planner relids to index of the partitioned rel, and building a
* PartitionedRelPruneInfo for each partitioned rel.
*
* In this phase we discover whether runtime pruning is needed at all; if
* not, we can avoid doing further work.
*/
relid_subpart_map = palloc0(sizeof(int) * root->simple_rel_array_size);
/*
* relid_subpart_map maps relid of a non-leaf partition to the index in
* 'partitioned_rels' of that rel (which will also be the index in the
* returned PartitionedRelPruneInfo list of the info for that partition).
*/
i = 1;
foreach(lc, partitioned_rels)
{
Index rti = lfirst_int(lc);
Assert(rti < root->simple_rel_array_size);
/* No duplicates please */
Assert(relid_subpart_map[rti] == 0);
relid_subpart_map[rti] = i++;
}
/* We now build a PartitionedRelPruneInfo for each partitioned rel */
foreach(lc, partitioned_rels)
{
Index rti = lfirst_int(lc);
RelOptInfo *subpart = find_base_rel(root, rti);
PartitionedRelPruneInfo *pinfo;
Bitmapset *present_parts;
int nparts = subpart->nparts;
int partnatts = subpart->part_scheme->partnatts;
int *subplan_map;
int *subpart_map;
Oid *relid_map;
List *partprunequal;
List *pruning_steps;
bool contradictory;
/*
* Fill the mapping array.
*
* relid_subpart_map maps relid of a non-leaf partition to the index
* in 'partitioned_rels' of that rel (which will also be the index in
* the returned PartitionedRelPruneInfo list of the info for that
* partition). We use 1-based indexes here, so that zero can
* represent an un-filled array entry.
*/
Assert(rti < root->simple_rel_array_size);
/* No duplicates please */
Assert(relid_subpart_map[rti] == 0);
relid_subpart_map[rti] = i++;
/*
* Translate pruning qual, if necessary, for this partition.
*
* The first item in the list is the target partitioned relation.
*/
if (!targetpart)
@ -411,6 +408,7 @@ make_partitionedrel_pruneinfo(PlannerInfo *root, RelOptInfo *parentrel,
targetpart->relids);
}
/* Convert pruning qual to pruning steps. */
pruning_steps = gen_partprune_steps(subpart, partprunequal,
&contradictory);
@ -428,6 +426,47 @@ make_partitionedrel_pruneinfo(PlannerInfo *root, RelOptInfo *parentrel,
return NIL;
}
/* Begin constructing the PartitionedRelPruneInfo for this rel */
pinfo = makeNode(PartitionedRelPruneInfo);
pinfo->rtindex = rti;
pinfo->pruning_steps = pruning_steps;
/* Remaining fields will be filled in the next loop */
pinfolist = lappend(pinfolist, pinfo);
/*
* Determine which pruning types should be enabled at this level. This
* also records paramids relevant to pruning steps in 'pinfo'.
*/
doruntimeprune |= analyze_partkey_exprs(pinfo, pruning_steps,
partnatts);
}
if (!doruntimeprune)
{
/* No run-time pruning required. */
pfree(relid_subpart_map);
return NIL;
}
/*
* Run-time pruning will be required, so initialize other information.
* That includes two maps -- one needed to convert partition indexes of
* leaf partitions to the indexes of their subplans in the subplan list,
* another needed to convert partition indexes of sub-partitioned
* partitions to the indexes of their PartitionedRelPruneInfo in the
* PartitionedRelPruneInfo list.
*/
foreach(lc, pinfolist)
{
PartitionedRelPruneInfo *pinfo = lfirst(lc);
RelOptInfo *subpart = find_base_rel(root, pinfo->rtindex);
Bitmapset *present_parts;
int nparts = subpart->nparts;
int *subplan_map;
int *subpart_map;
Oid *relid_map;
/*
* Construct the subplan and subpart maps for this partitioning level.
* Here we convert to zero-based indexes, with -1 for empty entries.
@ -459,30 +498,16 @@ make_partitionedrel_pruneinfo(PlannerInfo *root, RelOptInfo *parentrel,
present_parts = bms_add_member(present_parts, i);
}
pinfo = makeNode(PartitionedRelPruneInfo);
pinfo->rtindex = rti;
pinfo->pruning_steps = pruning_steps;
/* Record the maps and other information. */
pinfo->present_parts = present_parts;
pinfo->nparts = nparts;
pinfo->subplan_map = subplan_map;
pinfo->subpart_map = subpart_map;
pinfo->relid_map = relid_map;
/* Determine which pruning types should be enabled at this level */
doruntimeprune |= analyze_partkey_exprs(pinfo, pruning_steps,
partnatts);
pinfolist = lappend(pinfolist, pinfo);
}
pfree(relid_subpart_map);
if (!doruntimeprune)
{
/* No run-time pruning required. */
return NIL;
}
*matchedsubplans = subplansfound;
return pinfolist;
@ -2907,6 +2932,9 @@ pull_exec_paramids_walker(Node *node, Bitmapset **context)
*
* Returns true if any executor partition pruning should be attempted at this
* level. Also fills fields of *pinfo to record how to process each step.
*
* Note: when this is called, not much of *pinfo is valid; but that's OK
* since we only use it as an output area.
*/
static bool
analyze_partkey_exprs(PartitionedRelPruneInfo *pinfo, List *steps,