Changeset: b7b42321f8cd for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/b7b42321f8cd
Modified Files:
sql/server/rel_optimizer.c
Branch: default
Log Message:
If the other expression has no nils then the output will be unique if the
expression has duplicate nils
diffs (36 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
@@ -5351,21 +5351,21 @@ rewrite_joins2semi(visitor *v, sql_rel *
right_unique = false;
/* if all columns used in equi-joins from one of the sides are
unique, the join can be rewritten into a semijoin */
for (node *n=rel->exps->h; n && (left_unique || right_unique);
n = n->next) {
- sql_exp *e = n->data;
-
- if (!is_compare(e->type) || e->flag != cmp_equal ||
exp_has_func(e->l) || exp_has_func(e->r)) {
+ sql_exp *e = n->data, *el = e->l, *er = e->r;
+
+ if (!is_compare(e->type) || e->flag != cmp_equal ||
exp_has_func(el) || exp_has_func(er)) {
left_unique = right_unique = false;
} else {
int found = 0;
- if (left_unique && (found =
find_projection_for_join2semi(l, e->l)) > NO_EXP_FOUND)
- left_unique &= (found ==
ALL_VALUES_DISTINCT || (found == MAY_HAVE_DUPLICATE_NULLS && !is_semantics(e)));
- if (left_unique && (found =
find_projection_for_join2semi(l, e->r)) > NO_EXP_FOUND)
- left_unique &= (found ==
ALL_VALUES_DISTINCT || (found == MAY_HAVE_DUPLICATE_NULLS && !is_semantics(e)));
- if (right_unique && (found =
find_projection_for_join2semi(r, e->l)) > NO_EXP_FOUND)
- right_unique &= (found ==
ALL_VALUES_DISTINCT || (found == MAY_HAVE_DUPLICATE_NULLS && !is_semantics(e)));
- if (right_unique && (found =
find_projection_for_join2semi(r, e->r)) > NO_EXP_FOUND)
- right_unique &= (found ==
ALL_VALUES_DISTINCT || (found == MAY_HAVE_DUPLICATE_NULLS && !is_semantics(e)));
+ if (left_unique && (found =
find_projection_for_join2semi(l, el)) > NO_EXP_FOUND)
+ left_unique &= (found ==
ALL_VALUES_DISTINCT || (found == MAY_HAVE_DUPLICATE_NULLS && (!is_semantics(e)
|| !has_nil(er))));
+ if (left_unique && (found =
find_projection_for_join2semi(l, er)) > NO_EXP_FOUND)
+ left_unique &= (found ==
ALL_VALUES_DISTINCT || (found == MAY_HAVE_DUPLICATE_NULLS && (!is_semantics(e)
|| !has_nil(el))));
+ if (right_unique && (found =
find_projection_for_join2semi(r, el)) > NO_EXP_FOUND)
+ right_unique &= (found ==
ALL_VALUES_DISTINCT || (found == MAY_HAVE_DUPLICATE_NULLS && (!is_semantics(e)
|| !has_nil(er))));
+ if (right_unique && (found =
find_projection_for_join2semi(r, er)) > NO_EXP_FOUND)
+ right_unique &= (found ==
ALL_VALUES_DISTINCT || (found == MAY_HAVE_DUPLICATE_NULLS && (!is_semantics(e)
|| !has_nil(el))));
}
}
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