Changeset: e9bbb982c19f for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/e9bbb982c19f
Modified Files:
sql/server/rel_optimizer.c
Branch: Jul2021
Log Message:
Stack overflow checks and don't create extra reference to not empty relation
diffs (105 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
@@ -5270,14 +5270,16 @@ rel_push_join_down_outer(visitor *v, sql
}
static int
-rel_is_empty( sql_rel *rel )
-{
+rel_is_empty(mvc *sql, sql_rel *rel)
+{
+ if (mvc_highwater(sql))
+ return 0;
if ((is_innerjoin(rel->op) || is_left(rel->op) || is_right(rel->op) ||
is_semi(rel->op)) && !list_empty(rel->exps)) {
sql_rel *l = rel->l, *r = rel->r;
sql_exp *je;
- if (((is_innerjoin(rel->op) || is_left(rel->op) ||
is_semi(rel->op)) && rel_is_empty(l)) ||
- ((is_innerjoin(rel->op) || is_right(rel->op)) &&
rel_is_empty(r)))
+ if (((is_innerjoin(rel->op) || is_left(rel->op) ||
is_semi(rel->op)) && rel_is_empty(sql, l)) ||
+ ((is_innerjoin(rel->op) || is_right(rel->op)) &&
rel_is_empty(sql, r)))
return 1;
/* check */
if ((je = rel_is_join_on_pkey(rel, true))) {
@@ -5292,9 +5294,9 @@ rel_is_empty( sql_rel *rel )
if (is_simple_project(rel->op) || (is_groupby(rel->op) &&
!list_empty(rel->r)) || is_select(rel->op) ||
is_topn(rel->op) || is_sample(rel->op) || is_inter(rel->op) ||
is_except(rel->op)) {
if (rel->l)
- return rel_is_empty(rel->l);
+ return rel_is_empty(sql, rel->l);
} else if (is_innerjoin(rel->op) && list_empty(rel->exps)) { /*
cartesian product */
- return rel_is_empty(rel->l) || rel_is_empty(rel->r);
+ return rel_is_empty(sql, rel->l) || rel_is_empty(sql, rel->r);
}
return 0;
}
@@ -5303,21 +5305,28 @@ rel_is_empty( sql_rel *rel )
static inline sql_rel *
rel_remove_empty_join(visitor *v, sql_rel *rel)
{
- if (!is_union(rel->op))
+ if (!is_union(rel->op) || rel_is_ref(rel))
return rel;
/* For half empty unions replace by projects */
- sql_rel *l = rel->l, *r = rel->r;
-
- if (rel_is_empty(l)) {
+ if (!rel_is_ref(rel->l) && rel_is_empty(v->sql, rel->l)) {
+ sql_rel *r = rel->r;
+ if (!is_project(r->op))
+ r = rel_project(v->sql->sa, r, rel_projections(v->sql,
r, NULL, 1, 1));
+ rel_rename_exps(v->sql, rel->exps, r->exps);
+ rel->r = NULL;
+ rel_destroy(rel);
v->changes++;
+ return r;
+ }
+ if (!rel_is_ref(rel->r) && rel_is_empty(v->sql, rel->r)) {
+ sql_rel *l = rel->l;
+ if (!is_project(l->op))
+ l = rel_project(v->sql->sa, l, rel_projections(v->sql,
l, NULL, 1, 1));
+ rel_rename_exps(v->sql, rel->exps, l->exps);
rel->l = NULL;
- rel_destroy(l);
- return rel_inplace_project(v->sql->sa, rel, rel_dup(r),
rel->exps);
- } else if (rel_is_empty(r)) {
+ rel_destroy(rel);
v->changes++;
- rel->r = NULL;
- rel_destroy(r);
- return rel_inplace_project(v->sql->sa, rel, rel_dup(l),
rel->exps);
+ return l;
}
return rel;
}
@@ -9433,7 +9442,7 @@ exp_is_zero_rows(mvc *sql, sql_rel *rel,
sql_table *t;
node *n;
- if (!rel)
+ if (!rel || mvc_highwater(sql))
return 0;
rel = exp_skip_output_parts(rel);
if (is_select(rel->op) && rel->l) {
@@ -9496,9 +9505,9 @@ statistics, similarly to the merge table
static inline sql_rel *
rel_remove_union_partitions(visitor *v, sql_rel *rel)
{
- if (!is_union(rel->op))
+ if (!is_union(rel->op) || rel_is_ref(rel))
return rel;
- if (exp_is_zero_rows(v->sql, rel->l, NULL)) {
+ if (!rel_is_ref(rel->l) && exp_is_zero_rows(v->sql, rel->l, NULL)) {
sql_rel *r = rel->r;
if (!is_project(r->op))
r = rel_project(v->sql->sa, r, rel_projections(v->sql,
r, NULL, 1, 1));
@@ -9508,7 +9517,7 @@ rel_remove_union_partitions(visitor *v,
v->changes++;
return r;
}
- if (exp_is_zero_rows(v->sql, rel->r, NULL)) {
+ if (!rel_is_ref(rel->r) && exp_is_zero_rows(v->sql, rel->r, NULL)) {
sql_rel *l = rel->l;
if (!is_project(l->op))
l = rel_project(v->sql->sa, l, rel_projections(v->sql,
l, NULL, 1, 1));
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