Changeset: 2e856c170afa for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/2e856c170afa
Modified Files:
sql/server/rel_optimize_sel.c
Branch: pp_hashjoin
Log Message:
when pushing down selects, we now try to push it to both sides if possible
(using transitive info from the join).
diffs (90 lines):
diff --git a/sql/server/rel_optimize_sel.c b/sql/server/rel_optimize_sel.c
--- a/sql/server/rel_optimize_sel.c
+++ b/sql/server/rel_optimize_sel.c
@@ -1340,7 +1340,6 @@ push_up_join_exps( mvc *sql, sql_rel *re
}
}
-/* simple transitivity rule: a = b and b = c -> a = c */
static sql_rel *
transitivity_rule(visitor *v, sql_rel *rel)
{
@@ -1666,7 +1665,7 @@ remove_blocking_selects( mvc *sql, sql_r
case op_select:
if (p) {
sql_rel *l = rel->l;
- if (is_single(rel) || !is_join(l->op))
+ if (is_single(rel) || l->op != op_join)
return rel;
if (!list_empty(rel->exps)) {
p->exps = list_join(p->exps, rel->exps);
@@ -4642,6 +4641,49 @@ filter_column_in_partition_by_columns(sq
return false;
}
+/* transitivity rule on a = b and a = 'constant' => b = 'constant' */
+static void
+try_duplicate_select(visitor *v, sql_rel *r, sql_exp *e, bool leftside)
+{
+ if (!e || !r || e->type != e_cmp || e->flag != cmp_equal || is_anti(e)
|| list_empty(r->exps) || rel_is_ref(r))
+ return;
+ sql_exp *el = e->l, *er = e->r;
+ if (!exp_is_atom(er))
+ return;
+ for (node *n = r->exps->h; n; n = n->next) {
+ sql_exp *je = n->data;
+
+ if (je->type == e_cmp && je->flag == cmp_equal && !is_anti(je))
{
+ sql_exp *jel = je->l, *jer = je->r, *ne = NULL;
+ if (jel->nid == el->nid) {
+ if (!leftside && rel_rebind_exp(v->sql, r->r,
jer)) /* check that jer is from right side */
+ ne = jer;
+ if (leftside && rel_rebind_exp(v->sql, r->l,
jer)) /* check that jer is from right side */
+ ne = jer;
+ }
+ if (jer->nid == el->nid) {
+ if (!leftside && rel_rebind_exp(v->sql, r->r,
jel)) /* check that jer is from right side */
+ ne = jel;
+ if (leftside && rel_rebind_exp(v->sql, r->l,
jel)) /* check that jer is from right side */
+ ne = jel;
+ }
+ if (ne) {
+ ne = exp_compare(v->sql->sa, ne, er, cmp_equal);
+ sql_rel *s = leftside ? r->l : r->r;
+ if (!is_select(s->op)) {
+ if (leftside)
+ r->l = rel_select(v->sql->sa,
s, ne);
+ else
+ r->r = rel_select(v->sql->sa,
s, ne);
+ } else {
+ rel_select_add_exp(v->sql->sa, s, ne);
+ }
+ break;
+ }
+ }
+ }
+}
+
/*
* Push select down, pushes the selects through (simple) projections. Also
* it cleans up the projections which become useless.
@@ -4732,16 +4774,19 @@ rel_push_select_down(visitor *v, sql_rel
sql_exp *e = n->data;
if (!exp_unsafe(e, false, true)) {
+ /* here we should also check if we need to
duplicate the select expression the other side ! */
if (left && rel_rebind_exp(v->sql, jl, e)) {
if (!is_select(jl->op) ||
rel_is_ref(jl))
r->l = jl =
rel_select(v->sql->sa, jl, NULL);
rel_select_add_exp(v->sql->sa, jl, e);
+ try_duplicate_select(v, r, e, false);
list_remove_node(exps, NULL, n);
v->changes++;
} else if (right && rel_rebind_exp(v->sql, jr,
e)) {
if (!is_select(jr->op) ||
rel_is_ref(jr))
r->r = jr =
rel_select(v->sql->sa, jr, NULL);
rel_select_add_exp(v->sql->sa, jr, e);
+ try_duplicate_select(v, r, e, true);
list_remove_node(exps, NULL, n);
v->changes++;
}
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