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-rw-r--r--contrib/postgres_fdw/postgres_fdw.c2
-rw-r--r--src/backend/optimizer/path/costsize.c3
-rw-r--r--src/backend/optimizer/path/indxpath.c1
-rw-r--r--src/backend/optimizer/plan/planner.c10
-rw-r--r--src/backend/optimizer/prep/prepunion.c1
-rw-r--r--src/backend/optimizer/util/pathnode.c1
-rw-r--r--src/backend/utils/adt/selfuncs.c22
-rw-r--r--src/include/utils/selfuncs.h17
8 files changed, 49 insertions, 8 deletions
diff --git a/contrib/postgres_fdw/postgres_fdw.c b/contrib/postgres_fdw/postgres_fdw.c
index a4babed2b04..20b25935ce6 100644
--- a/contrib/postgres_fdw/postgres_fdw.c
+++ b/contrib/postgres_fdw/postgres_fdw.c
@@ -3087,7 +3087,7 @@ estimate_path_cost_size(PlannerInfo *root,
numGroups = estimate_num_groups(root,
get_sortgrouplist_exprs(root->parse->groupClause,
fpinfo->grouped_tlist),
- input_rows, NULL);
+ input_rows, NULL, NULL);
/*
* Get the retrieved_rows and rows estimates. If there are HAVING
diff --git a/src/backend/optimizer/path/costsize.c b/src/backend/optimizer/path/costsize.c
index a25b674a192..b92c9485882 100644
--- a/src/backend/optimizer/path/costsize.c
+++ b/src/backend/optimizer/path/costsize.c
@@ -1969,7 +1969,8 @@ cost_incremental_sort(Path *path,
/* Estimate number of groups with equal presorted keys. */
if (!unknown_varno)
- input_groups = estimate_num_groups(root, presortedExprs, input_tuples, NULL);
+ input_groups = estimate_num_groups(root, presortedExprs, input_tuples,
+ NULL, NULL);
group_tuples = input_tuples / input_groups;
group_input_run_cost = input_run_cost / input_groups;
diff --git a/src/backend/optimizer/path/indxpath.c b/src/backend/optimizer/path/indxpath.c
index ff536e6b24b..53b24e9e8c8 100644
--- a/src/backend/optimizer/path/indxpath.c
+++ b/src/backend/optimizer/path/indxpath.c
@@ -1990,6 +1990,7 @@ adjust_rowcount_for_semijoins(PlannerInfo *root,
nunique = estimate_num_groups(root,
sjinfo->semi_rhs_exprs,
nraw,
+ NULL,
NULL);
if (rowcount > nunique)
rowcount = nunique;
diff --git a/src/backend/optimizer/plan/planner.c b/src/backend/optimizer/plan/planner.c
index f529d107d29..0886bf4ae8f 100644
--- a/src/backend/optimizer/plan/planner.c
+++ b/src/backend/optimizer/plan/planner.c
@@ -3702,7 +3702,8 @@ get_number_of_groups(PlannerInfo *root,
double numGroups = estimate_num_groups(root,
groupExprs,
path_rows,
- &gset);
+ &gset,
+ NULL);
gs->numGroups = numGroups;
rollup->numGroups += numGroups;
@@ -3727,7 +3728,8 @@ get_number_of_groups(PlannerInfo *root,
double numGroups = estimate_num_groups(root,
groupExprs,
path_rows,
- &gset);
+ &gset,
+ NULL);
gs->numGroups = numGroups;
gd->dNumHashGroups += numGroups;
@@ -3743,7 +3745,7 @@ get_number_of_groups(PlannerInfo *root,
target_list);
dNumGroups = estimate_num_groups(root, groupExprs, path_rows,
- NULL);
+ NULL, NULL);
}
}
else if (parse->groupingSets)
@@ -4792,7 +4794,7 @@ create_distinct_paths(PlannerInfo *root,
parse->targetList);
numDistinctRows = estimate_num_groups(root, distinctExprs,
cheapest_input_path->rows,
- NULL);
+ NULL, NULL);
}
/*
diff --git a/src/backend/optimizer/prep/prepunion.c b/src/backend/optimizer/prep/prepunion.c
index becdcbb8725..037dfaacfd4 100644
--- a/src/backend/optimizer/prep/prepunion.c
+++ b/src/backend/optimizer/prep/prepunion.c
@@ -338,6 +338,7 @@ recurse_set_operations(Node *setOp, PlannerInfo *root,
*pNumGroups = estimate_num_groups(subroot,
get_tlist_exprs(subquery->targetList, false),
subpath->rows,
+ NULL,
NULL);
}
}
diff --git a/src/backend/optimizer/util/pathnode.c b/src/backend/optimizer/util/pathnode.c
index 69b83071cf2..d5c66780ac8 100644
--- a/src/backend/optimizer/util/pathnode.c
+++ b/src/backend/optimizer/util/pathnode.c
@@ -1713,6 +1713,7 @@ create_unique_path(PlannerInfo *root, RelOptInfo *rel, Path *subpath,
pathnode->path.rows = estimate_num_groups(root,
sjinfo->semi_rhs_exprs,
rel->rows,
+ NULL,
NULL);
numCols = list_length(sjinfo->semi_rhs_exprs);
diff --git a/src/backend/utils/adt/selfuncs.c b/src/backend/utils/adt/selfuncs.c
index 7e41bc56418..0963e2701cb 100644
--- a/src/backend/utils/adt/selfuncs.c
+++ b/src/backend/utils/adt/selfuncs.c
@@ -3241,6 +3241,7 @@ typedef struct
Node *var; /* might be an expression, not just a Var */
RelOptInfo *rel; /* relation it belongs to */
double ndistinct; /* # distinct values */
+ bool isdefault; /* true if DEFAULT_NUM_DISTINCT was used */
} GroupVarInfo;
static List *
@@ -3287,6 +3288,7 @@ add_unique_group_var(PlannerInfo *root, List *varinfos,
varinfo->var = var;
varinfo->rel = vardata->rel;
varinfo->ndistinct = ndistinct;
+ varinfo->isdefault = isdefault;
varinfos = lappend(varinfos, varinfo);
return varinfos;
}
@@ -3311,6 +3313,12 @@ add_unique_group_var(PlannerInfo *root, List *varinfos,
* pgset - NULL, or a List** pointing to a grouping set to filter the
* groupExprs against
*
+ * Outputs:
+ * estinfo - When passed as non-NULL, the function will set bits in the
+ * "flags" field in order to provide callers with additional information
+ * about the estimation. Currently, we only set the SELFLAG_USED_DEFAULT
+ * bit if we used any default values in the estimation.
+ *
* Given the lack of any cross-correlation statistics in the system, it's
* impossible to do anything really trustworthy with GROUP BY conditions
* involving multiple Vars. We should however avoid assuming the worst
@@ -3358,7 +3366,7 @@ add_unique_group_var(PlannerInfo *root, List *varinfos,
*/
double
estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
- List **pgset)
+ List **pgset, EstimationInfo *estinfo)
{
List *varinfos = NIL;
double srf_multiplier = 1.0;
@@ -3366,6 +3374,10 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
ListCell *l;
int i;
+ /* Zero the estinfo output parameter, if non-NULL */
+ if (estinfo != NULL)
+ memset(estinfo, 0, sizeof(EstimationInfo));
+
/*
* We don't ever want to return an estimate of zero groups, as that tends
* to lead to division-by-zero and other unpleasantness. The input_rows
@@ -3577,6 +3589,14 @@ estimate_num_groups(PlannerInfo *root, List *groupExprs, double input_rows,
if (relmaxndistinct < varinfo2->ndistinct)
relmaxndistinct = varinfo2->ndistinct;
relvarcount++;
+
+ /*
+ * When varinfo2's isdefault is set then we'd better set
+ * the SELFLAG_USED_DEFAULT bit in the EstimationInfo.
+ */
+ if (estinfo != NULL && varinfo2->isdefault)
+ estinfo->flags |= SELFLAG_USED_DEFAULT;
+
}
/* we're done with this relation */
diff --git a/src/include/utils/selfuncs.h b/src/include/utils/selfuncs.h
index f9be539602b..78cde58acc1 100644
--- a/src/include/utils/selfuncs.h
+++ b/src/include/utils/selfuncs.h
@@ -68,6 +68,20 @@
p = 1.0; \
} while (0)
+/*
+ * A set of flags which some selectivity estimation functions can pass back to
+ * callers to provide further details about some assumptions which were made
+ * during the estimation.
+ */
+#define SELFLAG_USED_DEFAULT (1 << 0) /* Estimation fell back on one
+ * of the DEFAULTs as defined
+ * above. */
+
+typedef struct EstimationInfo
+{
+ uint32 flags; /* Flags, as defined above to mark special
+ * properties of the estimation. */
+} EstimationInfo;
/* Return data from examine_variable and friends */
typedef struct VariableStatData
@@ -197,7 +211,8 @@ extern void mergejoinscansel(PlannerInfo *root, Node *clause,
Selectivity *rightstart, Selectivity *rightend);
extern double estimate_num_groups(PlannerInfo *root, List *groupExprs,
- double input_rows, List **pgset);
+ double input_rows, List **pgset,
+ EstimationInfo *estinfo);
extern void estimate_hash_bucket_stats(PlannerInfo *root,
Node *hashkey, double nbuckets,
generated by cgit v1.2.3 (git 2.25.1) at 2025-05-21 00:26:41 +0000