Changeset: a8cfb6929d1b for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB?cmd=changeset;node=a8cfb6929d1b
Modified Files:
sql/server/rel_optimizer.c
Branch: Jun2020
Log Message:
If the testing projection for join2semi needs distinct, the semijoin rewrite
can still be made
diffs (21 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
@@ -5476,7 +5476,7 @@ find_simple_projection_for_join2semi(sql
sql_rel *res = NULL;
sql_exp *found = NULL;
- if (is_groupby(rel->op) || find_prop(e->p,
PROP_HASHCOL))
+ if (is_groupby(rel->op) || need_distinct(rel) ||
find_prop(e->p, PROP_HASHCOL))
return true;
found = rel_find_exp_and_corresponding_rel(rel->l, e,
&res); /* grouping column on inner relation */
@@ -5484,7 +5484,7 @@ find_simple_projection_for_join2semi(sql
if (find_prop(found->p, PROP_HASHCOL)) /*
primary key always unique */
return true;
if (found->type == e_column && found->card <=
CARD_AGGR) {
- if (!is_groupby(res->op) &&
list_length(res->exps) != 1)
+ if (!(is_groupby(res->op) ||
need_distinct(res)) && list_length(res->exps) != 1)
return false;
for (node *n = res->exps->h ; n ; n =
n->next) { /* must be the single column in the group by expression list */
sql_exp *e = n->data;
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