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Assorted cosmetic cleanup of run-time-partition-pruning code.

Use "subplan" rather than "subnode" to refer to the child plans of
a partitioning Append; this seems a bit more specific and hence
clearer.  Improve assorted comments.  No non-cosmetic changes.

David Rowley and Tom Lane

Discussion: https://postgr.es/m/CAFj8pRBjrufA3ocDm8o4LPGNye9Y+pm1b9kCwode4X04CULG3g@mail.gmail.com
This commit is contained in:
Tom Lane
2018-06-10 18:24:34 -04:00
parent 939449de0e
commit 321f648a31
7 changed files with 148 additions and 157 deletions

View File

@@ -4,28 +4,24 @@
* Support for partition pruning during query planning and execution
*
* This module implements partition pruning using the information contained in
* table's partition descriptor, query clauses, and run-time parameters.
* a table's partition descriptor, query clauses, and run-time parameters.
*
* During planning, clauses that can be matched to the table's partition key
* are turned into a set of "pruning steps", which are then executed to
* produce a set of partitions (as indexes of the RelOptInfo->part_rels array)
* that satisfy the constraints in the step. Partitions not in the set are said
* to have been pruned.
* identify a set of partitions (as indexes in the RelOptInfo->part_rels
* array) that satisfy the constraints in the step. Partitions not in the set
* are said to have been pruned.
*
* A base pruning step may also consist of expressions whose values are only
* known during execution, such as Params, in which case pruning cannot occur
* A base pruning step may involve expressions whose values are only known
* during execution, such as Params, in which case pruning cannot occur
* entirely during planning. In that case, such steps are included alongside
* the plan, so that they can be used by the executor for further pruning.
*
* There are two kinds of pruning steps: a "base" pruning step, which contains
* information extracted from one or more clauses that are matched to the
* (possibly multi-column) partition key, such as the expressions whose values
* to match against partition bounds and operator strategy to associate to
* each expression. The other kind is a "combine" pruning step, which combines
* the outputs of some other steps using the appropriate combination method.
* All steps that are constructed are executed in succession such that for any
* "combine" step, all of the steps whose output it depends on are executed
* first and their ouput preserved.
* There are two kinds of pruning steps. A "base" pruning step represents
* tests on partition key column(s), typically comparisons to expressions.
* A "combine" pruning step represents a Boolean connector (AND/OR), and
* combines the outputs of some previous steps using the appropriate
* combination method.
*
* See gen_partprune_steps_internal() for more details on step generation.
*
@@ -65,19 +61,18 @@
*/
typedef struct PartClauseInfo
{
int keyno; /* Partition key number (0 to partnatts - 1) */
Oid opno; /* operator used to compare partkey to 'expr' */
int keyno; /* Partition key number (0 to partnatts - 1) */
Oid opno; /* operator used to compare partkey to expr */
bool op_is_ne; /* is clause's original operator <> ? */
Expr *expr; /* expr the partition key is compared to */
Oid cmpfn; /* Oid of function to compare 'expr' to the
* partition key */
int op_strategy; /* cached info. */
int op_strategy; /* btree strategy identifying the operator */
} PartClauseInfo;
/*
* PartClauseMatchStatus
* Describes the result match_clause_to_partition_key produces for a
* given clause and the partition key to match with that are passed to it
* Describes the result of match_clause_to_partition_key()
*/
typedef enum PartClauseMatchStatus
{
@@ -177,6 +172,7 @@ static bool match_boolean_partition_clause(Oid partopfamily, Expr *clause,
static bool partkey_datum_from_expr(PartitionPruneContext *context,
Expr *expr, int stateidx, Datum *value);
/*
* make_partition_pruneinfo
* Build List of PartitionPruneInfos, one for each 'partitioned_rels'.
@@ -196,18 +192,18 @@ make_partition_pruneinfo(PlannerInfo *root, List *partition_rels,
List *subpaths, List *prunequal)
{
RelOptInfo *targetpart = NULL;
ListCell *lc;
List *pinfolist = NIL;
int *relid_subnode_map;
int *relid_subpart_map;
int i;
bool doruntimeprune = false;
int *relid_subplan_map;
int *relid_subpart_map;
ListCell *lc;
int i;
/*
* Allocate two arrays to store the 1-based indexes of the 'subpaths' and
* 'partitioned_rels' by relid.
*/
relid_subnode_map = palloc0(sizeof(int) * root->simple_rel_array_size);
relid_subplan_map = palloc0(sizeof(int) * root->simple_rel_array_size);
relid_subpart_map = palloc0(sizeof(int) * root->simple_rel_array_size);
i = 1;
@@ -219,7 +215,7 @@ make_partition_pruneinfo(PlannerInfo *root, List *partition_rels,
Assert(IS_SIMPLE_REL(pathrel));
Assert(pathrel->relid < root->simple_rel_array_size);
relid_subnode_map[pathrel->relid] = i++;
relid_subplan_map[pathrel->relid] = i++;
}
/* Likewise for the partition_rels */
@@ -243,7 +239,7 @@ make_partition_pruneinfo(PlannerInfo *root, List *partition_rels,
Bitmapset *present_parts;
int nparts = subpart->nparts;
int partnatts = subpart->part_scheme->partnatts;
int *subnode_map;
int *subplan_map;
int *subpart_map;
List *partprunequal;
List *pruning_steps;
@@ -289,7 +285,7 @@ make_partition_pruneinfo(PlannerInfo *root, List *partition_rels,
return NIL;
}
subnode_map = (int *) palloc(nparts * sizeof(int));
subplan_map = (int *) palloc(nparts * sizeof(int));
subpart_map = (int *) palloc(nparts * sizeof(int));
present_parts = NULL;
@@ -302,19 +298,18 @@ make_partition_pruneinfo(PlannerInfo *root, List *partition_rels,
for (i = 0; i < nparts; i++)
{
RelOptInfo *partrel = subpart->part_rels[i];
int subnodeidx = relid_subnode_map[partrel->relid] - 1;
int subplanidx = relid_subplan_map[partrel->relid] - 1;
int subpartidx = relid_subpart_map[partrel->relid] - 1;
subnode_map[i] = subnodeidx;
subplan_map[i] = subplanidx;
subpart_map[i] = subpartidx;
/*
* Record the indexes of all the partition indexes that we have
* subnodes or subparts for. This allows an optimization to skip
* attempting any run-time pruning when no Params are found
* matching the partition key at this level.
* subplans or subparts for. This allows an optimization to skip
* attempting any run-time pruning when it's irrelevant.
*/
if (subnodeidx >= 0 || subpartidx >= 0)
if (subplanidx >= 0 || subpartidx >= 0)
present_parts = bms_add_member(present_parts, i);
}
@@ -325,16 +320,17 @@ make_partition_pruneinfo(PlannerInfo *root, List *partition_rels,
pinfo->pruning_steps = pruning_steps;
pinfo->present_parts = present_parts;
pinfo->nparts = nparts;
pinfo->subnode_map = subnode_map;
pinfo->subplan_map = subplan_map;
pinfo->subpart_map = subpart_map;
/* Determine which pruning types should be enabled at this level */
doruntimeprune |= analyze_partkey_exprs(pinfo, pruning_steps, partnatts);
doruntimeprune |= analyze_partkey_exprs(pinfo, pruning_steps,
partnatts);
pinfolist = lappend(pinfolist, pinfo);
}
pfree(relid_subnode_map);
pfree(relid_subplan_map);
pfree(relid_subpart_map);
if (doruntimeprune)