Changeset: d9ec566d2152 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/d9ec566d2152
Modified Files:
sql/server/rel_statistics.c
Branch: properties
Log Message:
For a grouping column, compute number of possible groups/rows using (max-min+1)
for numeric types. Then compute the result with MIN((max-min+1),nuniques)
diffs (85 lines):
diff --git a/sql/server/rel_statistics.c b/sql/server/rel_statistics.c
--- a/sql/server/rel_statistics.c
+++ b/sql/server/rel_statistics.c
@@ -616,7 +616,7 @@ trivial_project_exp_card(sql_exp *e)
}
static BUN
-rel_calc_nuniques(sql_rel *l, list *exps)
+rel_calc_nuniques(mvc *sql, sql_rel *l, list *exps)
{
BUN lv = get_rel_count(l);
@@ -629,14 +629,28 @@ rel_calc_nuniques(sql_rel *l, list *exps
sql_exp *e = n->data;
sql_rel *bt = NULL;
prop *p = NULL;
+ BUN euniques = BUN_NONE;
+ atom *min, *max, *sub = NULL;
+ sql_subtype *tp = exp_subtype(e);
+ sql_class ec = tp ? tp->type->eclass : EC_STRING; /* if
'e' has no type (eg parameter), use a non-number type to fail condition */
if ((p = find_prop(e->p, PROP_NUNIQUES))) {
- nuniques = MAX(nuniques, (BUN) p->value.dval);
+ euniques = (BUN) p->value.dval;
} else if (e->type == e_column &&
rel_find_exp_and_corresponding_rel(l, e, false, &bt, NULL) && bt && (p =
find_prop(bt->p, PROP_COUNT))) {
- nuniques = MAX(nuniques, p->value.lval);
- } else {
+ euniques = (BUN) p->value.lval;
+ }
+ /* use min to max range to compute number of possible
values in the domain for number types */
+ if ((EC_TEMP(ec)||ec==EC_NUM||ec==EC_MONTH||ec==EC_POS)
&&
+ (min = find_prop_and_get(e->p, PROP_MIN)) &&
(max = find_prop_and_get(e->p, PROP_MAX))) {
+ /* the range includes min and max, so the
atom_inc call is needed */
+ /* if 'euniques' has number of distinct values,
compute min between both */
+ if ((sub = atom_sub(sql->sa, max, min)) && (sub
= atom_inc(sql->sa, sub)) && (sub = atom_cast(sql->sa, sub,
sql_bind_localtype("oid"))))
+ euniques = MIN(euniques, (BUN)
sub->data.val.oval);
+ }
+ if (euniques != BUN_NONE)
+ nuniques = MAX(nuniques, euniques); /* the
highest cardinality sets the estimation */
+ else
nuniques = BUN_NONE;
- }
}
if (nuniques != BUN_NONE)
return nuniques;
@@ -699,8 +713,8 @@ rel_get_statistics_(visitor *v, sql_rel
/* propagate row count */
if (is_union(rel->op)) {
- BUN lv = need_distinct(rel) ? rel_calc_nuniques(l,
l->exps) : get_rel_count(l),
- rv = need_distinct(rel) ? rel_calc_nuniques(r,
r->exps) : get_rel_count(r);
+ BUN lv = need_distinct(rel) ? rel_calc_nuniques(v->sql,
l, l->exps) : get_rel_count(l),
+ rv = need_distinct(rel) ?
rel_calc_nuniques(v->sql, r, r->exps) : get_rel_count(r);
if (lv == 0 && rv == 0) { /* both sides empty */
if (can_be_pruned)
@@ -717,8 +731,8 @@ rel_get_statistics_(visitor *v, sql_rel
set_count_prop(v->sql->sa, rel, (rv > (BUN_MAX
- lv)) ? BUN_MAX : (lv + rv)); /* overflow check */
}
} else if (is_inter(rel->op) || is_except(rel->op)) {
- BUN lv = need_distinct(rel) ? rel_calc_nuniques(l,
l->exps) : get_rel_count(l),
- rv = need_distinct(rel) ? rel_calc_nuniques(r,
r->exps) : get_rel_count(r);
+ BUN lv = need_distinct(rel) ? rel_calc_nuniques(v->sql,
l, l->exps) : get_rel_count(l),
+ rv = need_distinct(rel) ?
rel_calc_nuniques(v->sql, r, r->exps) : get_rel_count(r);
if (lv == 0) { /* left side empty */
if (can_be_pruned)
@@ -855,7 +869,7 @@ rel_get_statistics_(visitor *v, sql_rel
case op_project: {
if (l) {
if (need_distinct(rel)) {
- set_count_prop(v->sql->sa, rel,
rel_calc_nuniques(l, rel->exps));
+ set_count_prop(v->sql->sa, rel,
rel_calc_nuniques(v->sql, l, rel->exps));
} else {
set_count_prop(v->sql->sa, rel,
get_rel_count(l));
}
@@ -875,7 +889,7 @@ rel_get_statistics_(visitor *v, sql_rel
if (list_empty(rel->r)) {
set_count_prop(v->sql->sa, rel, 1);
} else {
- set_count_prop(v->sql->sa, rel,
rel_calc_nuniques(l, rel->r));
+ set_count_prop(v->sql->sa, rel,
rel_calc_nuniques(v->sql, l, rel->r));
}
} break;
default:
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