Changeset: a0fa73f02941 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/a0fa73f02941
Modified Files:
sql/server/rel_statistics.c
Branch: properties
Log Message:
Do better overflow checks and fix count propagation for trivial joins and
selections
diffs (108 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
@@ -675,11 +675,7 @@ rel_get_statistics_(visitor *v, sql_rel
} else if (can_be_pruned && rv == 0 &&
!rel_is_ref(rel)) { /* right side empty */
rel = set_setop_side(v, rel, l);
} else if (lv != BUN_NONE && rv != BUN_NONE) {
- if ((lv + rv) < lv) {
- set_count_prop(v->sql->sa, rel, MAX(lv,
rv));
- } else {
- set_count_prop(v->sql->sa, rel, lv +
rv);
- }
+ 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 = get_rel_count(l), rv = get_rel_count(r);
@@ -750,7 +746,7 @@ rel_get_statistics_(visitor *v, sql_rel
case op_left:
case op_right:
case op_full: {
- BUN lv = get_rel_count(l), rv = get_rel_count(r),
uniques_estimate = BUN_NONE, join_idx_estimate = BUN_NONE;
+ BUN lv = get_rel_count(l), rv = get_rel_count(r),
uniques_estimate = BUN_MAX, join_idx_estimate = BUN_MAX;
if (!list_empty(rel->exps)) {
for (node *n = rel->exps->h ; n ; n = n->next) {
@@ -770,8 +766,8 @@ rel_get_statistics_(visitor *v, sql_rel
}
}
if ((p = find_prop(el->p,
PROP_NUNIQUES)) && (p2 = find_prop(er->p, PROP_NUNIQUES))) {
- BUN pv = (BUN)
p->value.dval, pv2 = (BUN) p2->value.dval, mul = pv * pv2;
- mul = mul < pv ?
MAX(pv, pv2) : mul; /* check for overflows */
+ BUN pv = (BUN)
p->value.dval, pv2 = (BUN) p2->value.dval,
+ mul = (pv == 0
|| pv2 == 0) ? 0 : ((pv2 > (BUN_MAX / pv)) ? BUN_MAX : (pv * pv2)); /* check
for overflows */
if (is_left(rel->op))
mul = MAX(mul,
lv);
@@ -785,38 +781,42 @@ rel_get_statistics_(visitor *v, sql_rel
}
}
}
- if (join_idx_estimate != BUN_NONE) {
+ if (join_idx_estimate != BUN_MAX) {
set_count_prop(v->sql->sa, rel,
join_idx_estimate);
- } else if (uniques_estimate != BUN_NONE) {
+ } else if (uniques_estimate != BUN_MAX) {
set_count_prop(v->sql->sa, rel,
uniques_estimate);
} else if (lv != BUN_NONE && rv != BUN_NONE) {
- if (list_empty(rel->exps) &&
is_outerjoin(rel->op)) { /* outer joins without conditions, sum cardinalities
instead of multiply */
- if ((lv + rv) < lv) {
- set_count_prop(v->sql->sa, rel,
MAX(lv, rv));
+ if (list_length(rel->exps) == 1 &&
(exp_is_false(rel->exps->h->data) || exp_is_null(rel->exps->h->data))) {
+ /* corner cases for outer joins */
+ if (is_left(rel->op)) {
+ set_count_prop(v->sql->sa, rel,
lv);
+ } else if (is_right(rel->op)) {
+ set_count_prop(v->sql->sa, rel,
rv);
+ } else if (is_full(rel->op)) {
+ set_count_prop(v->sql->sa, rel,
(rv > (BUN_MAX - lv)) ? BUN_MAX : (lv + rv)); /* overflow check */
} else {
- set_count_prop(v->sql->sa, rel,
lv + rv);
+ set_count_prop(v->sql->sa, rel,
0);
}
- } else if ((lv * rv) < lv) {
- set_count_prop(v->sql->sa, rel, MAX(lv,
rv));
+ } else if (lv == 0) {
+ set_count_prop(v->sql->sa, rel,
(is_right(rel->op) || is_full(rel->op)) ? rv : 0);
+ } else if (rv == 0) {
+ set_count_prop(v->sql->sa, rel,
(is_left(rel->op) || is_full(rel->op)) ? lv : 0);
} else {
- BUN mul = lv * rv;
-
- if (is_left(rel->op))
- set_count_prop(v->sql->sa, rel,
MAX(mul, lv));
- else if (is_right(rel->op))
- set_count_prop(v->sql->sa, rel,
MAX(mul, rv));
- else if (is_full(rel->op))
- set_count_prop(v->sql->sa, rel,
MAX(MAX(mul, lv), rv));
- else
- set_count_prop(v->sql->sa, rel,
lv * rv);
+ set_count_prop(v->sql->sa, rel, (rv >
(BUN_MAX / lv)) ? BUN_MAX : (lv * rv)); /* overflow check */
}
}
} break;
+ case op_anti:
+ set_count_prop(v->sql->sa, rel, get_rel_count(l));
+ break;
case op_semi:
- case op_anti:
case op_select: {
/* TODO calculate cardinalities using selectivities */
- set_count_prop(v->sql->sa, rel, get_rel_count(l));
+ if (list_length(rel->exps) == 1 &&
(exp_is_false(rel->exps->h->data) || exp_is_null(rel->exps->h->data))) {
+ set_count_prop(v->sql->sa, rel, 0);
+ } else {
+ set_count_prop(v->sql->sa, rel,
get_rel_count(l));
+ }
} break;
case op_project: {
if (l) {
@@ -859,7 +859,7 @@ rel_get_statistics_(visitor *v, sql_rel
sql_exp *le = rel->exps->h->data, *oe =
list_length(rel->exps) > 1 ? rel->exps->h->next->data : NULL;
if (oe && oe->l && !exp_is_null(oe)) { /* no parameters
*/
BUN offset = (BUN)
((atom*)oe->l)->data.val.lval;
- lv = offset > lv ? 0 : lv - offset;
+ lv = offset >= lv ? 0 : lv - offset;
}
if (le->l && !exp_is_null(le)) {
BUN limit = (BUN) ((atom*)le->l)->data.val.lval;
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