Changeset: cc438cd295bf for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=cc438cd295bf
Modified Files:
sql/server/rel_optimizer.c
Branch: Jun2020
Log Message:
Missed case, don't apply topN merging if the under relation has more than one
reference. Added merging of offsets if expressions are atoms
diffs (97 lines):
diff --git a/sql/server/rel_optimizer.c b/sql/server/rel_optimizer.c
--- a/sql/server/rel_optimizer.c
+++ b/sql/server/rel_optimizer.c
@@ -2079,28 +2079,47 @@ rel_push_topn_and_sample_down(mvc *sql,
operator_type relation_type = is_topn(rel->op) ? op_topn :
op_sample;
sql_rel *(*func) (sql_allocator *, sql_rel *, list *) =
is_topn(rel->op) ? rel_topn : rel_sample;
- /* nested topN relations without offset */
- if (r && is_topn(rel->op) && is_topn(r->op) &&
list_length(rel->exps) == 1 && list_length(r->exps) == 1) {
+ /* nested topN relations */
+ if (r && is_topn(rel->op) && is_topn(r->op) && !rel_is_ref(r)) {
sql_exp *topN1 = rel->exps->h->data, *topN2 =
r->exps->h->data;
-
- if (topN1->l && topN2->l) {
- atom *a1 = (atom *)topN1->l, *a2 = (atom
*)topN2->l;
-
- if (a1->tpe.type->localtype ==
a2->tpe.type->localtype && !a1->isnull && !a2->isnull) {
- if (atom_cmp(a1, a2) < 0) {
- rel->l = r->l;
- r->l = NULL;
- rel_destroy(r);
- (*changes)++;
- return rel;
- } else {
- rel->l = NULL;
- rel_destroy(rel);
- rel = r;
- (*changes)++;
- return rel;
+ sql_exp *offset1 = list_length(rel->exps) > 1 ?
rel->exps->h->next->data : NULL;
+ sql_exp *offset2 = list_length(r->exps) > 1 ?
r->exps->h->next->data : NULL;
+
+ if (topN1->l && topN2->l && (!offset1 || offset1->l) &&
(!offset2 || offset2->l)) { /* no parameters */
+ bool changed = false;
+
+ if ((!offset1 || (offset1->type == e_atom &&
offset1->l)) && (!offset2 || (offset2->type == e_atom && offset2->l))) { /*
only atoms */
+ if (!offset1 && offset2) {
+ list_append(rel->exps,
exp_copy(sql, offset2));
+ changed = true;
+ } else if (offset1 && offset2) { /* sum
offsets */
+ atom *b1 = (atom *)offset1->l,
*b2 = (atom *)offset2->l, *c = atom_add(b1, b2);
+
+ if (!c) /* error, don't apply
optimization, WARNING because of this the offset optimization must come before
the limit one */
+ return rel;
+ if (atom_cmp(c, b2) < 0) /*
overflow */
+ c = atom_int(sql->sa,
sql_bind_localtype("lng"), GDK_lng_max);
+ offset1->l = c;
+ changed = true;
}
}
+
+ if (topN1->type == e_atom && topN1->l &&
topN2->type == e_atom && topN2->l) { /* only atoms */
+ atom *a1 = (atom *)topN1->l, *a2 =
(atom *)topN2->l;
+
+ if (!a2->isnull && (a1->isnull ||
atom_cmp(a1, a2) >= 0)) { /* topN1 is not set or is larger than topN2 */
+ rel->exps->h->data =
exp_copy(sql, topN2);
+ changed = true;
+ }
+ }
+
+ if (changed) {
+ rel->l = r->l;
+ r->l = NULL;
+ rel_destroy(r);
+ (*changes)++;
+ return rel;
+ }
}
}
@@ -5505,6 +5524,8 @@ find_candidate_join2semi(sql_rel *rel, b
(c=find_candidate_join2semi(rel->r, swap)) != NULL)
return c;
}
+ if (is_topn(rel->op) || is_sample(rel->op))
+ return find_candidate_join2semi(rel->l, swap);
return NULL;
}
@@ -5521,6 +5542,8 @@ subrel_uses_exp_outside_subrel(sql_rel *
subrel_uses_exp_outside_subrel(rel->r, e, c))
return 1;
}
+ if (is_topn(rel->op) || is_sample(rel->op))
+ return subrel_uses_exp_outside_subrel(rel->l, e, c);
return 0;
}
@@ -5536,6 +5559,8 @@ rel_uses_exp_outside_subrel(sql_rel *rel
if (rel->l)
return subrel_uses_exp_outside_subrel(rel->l, e, c);
}
+ if (is_topn(rel->op) || is_sample(rel->op))
+ return subrel_uses_exp_outside_subrel(rel->l, e, c);
return 1;
}
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