Changeset: 1407c0aa2015 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/1407c0aa2015
Modified Files:
sql/server/rel_optimize_proj.c
Branch: balanced_union
Log Message:
Implements push_join_down_munion optimizer WIP
diffs (116 lines):
diff --git a/sql/server/rel_optimize_proj.c b/sql/server/rel_optimize_proj.c
--- a/sql/server/rel_optimize_proj.c
+++ b/sql/server/rel_optimize_proj.c
@@ -3524,7 +3524,8 @@ rel_push_join_down_union(visitor *v, sql
nl = rel_project(v->sql->sa, nl,
rel_projections(v->sql, nl, NULL, 1, 1));
nr = rel_project(v->sql->sa, nr,
rel_projections(v->sql, nr, NULL, 1, 1));
v->changes++;
- return rel_inplace_setop(v->sql, rel, nl, nr, op_union,
rel_projections(v->sql, rel, NULL, 1, 1));
+ return rel_inplace_setop(v->sql, rel, nl, nr, op_union,
+ rel_projections(v->sql, rel, NULL, 1,
1));
} else if (is_union(l->op) && !need_distinct(l) &&
!is_single(l) &&
is_union(r->op) && !need_distinct(r) &&
!is_single(r) && je) {
sql_rel *nl, *nr;
@@ -3684,6 +3685,102 @@ rel_push_join_down_union(visitor *v, sql
return rel;
}
+/*
+ * Push (semi)joins down unions, this is basically for merge tables, where
+ * we know that the fk-indices are split over two clustered merge tables.
+ */
+static inline sql_rel *
+rel_push_join_down_munion(visitor *v, sql_rel *rel)
+{
+ if ((is_join(rel->op) && !is_outerjoin(rel->op) && !is_single(rel)) ||
is_semi(rel->op)) {
+ sql_rel *l = rel->l, *r = rel->r, *ol = l, *or = r;
+ list *exps = rel->exps, *attr = rel->attr;
+ sql_exp *je = NULL;
+
+ /* we would like to optimize in place reference rels which point
+ * to replica tables and let the replica optimizer handle those
+ * later. otherwise we miss the push join down optimization due
+ * to the rel_is_ref bailout
+ */
+ if (rel_is_ref(l) && is_basetable(l->op) && l->l &&
isReplicaTable((sql_table*)l->l)) {
+ rel->l = rel_copy(v->sql, l, true);
+ rel_destroy(l);
+ }
+ if (rel_is_ref(r) && is_basetable(r->op) && r->l &&
isReplicaTable((sql_table*)r->l)) {
+ rel->r = rel_copy(v->sql, r, true);
+ rel_destroy(r);
+ }
+
+ // TODO: do we need to check if it's l/r are refs?
+ if (!l || !r || need_distinct(l) || need_distinct(r) ||
rel_is_ref(l) || rel_is_ref(r))
+ return rel;
+ if (l->op == op_project)
+ l = l->l;
+ if (r->op == op_project)
+ r = r->l;
+
+ /* both sides only if we have a join index ASSUMING pkey-fkey
are aligned */
+ // TODO: we could also check if the join cols are (not) unique
+ bool aligned_pk_fk = true;
+ if (!l || !r || (is_munion(l->op) && is_munion(r->op) &&
+ !(je = rel_is_join_on_pkey(rel, aligned_pk_fk))))
+ return rel;
+
+ // TODO: why? bailout for no semijoin without pkey joins
+ if (is_semi(rel->op) && is_munion(l->op) && !je)
+ return rel;
+
+ if (is_munion(l->op) && !need_distinct(l) && !is_single(l) &&
+ !is_munion(r->op)){
+ /* join(munion(a,b,c), d) -> munion(join(a,d),
join(b,d), join(c,d)) */
+ for (node *n = ((list*)l->l)->h; n; n = n->next) {
+ sql_rel *pc = rel_dup(n->data);
+ if (!is_project(pc->op))
+ pc = rel_project(v->sql->sa, pc,
rel_projections(v->sql, pc, NULL, 1, 1));
+ rel_rename_exps(v->sql, l->exps, pc->exps);
+ if (l != ol) {
+ pc = rel_project(v->sql->sa, pc, NULL);
+ pc->exps = exps_copy(v->sql, ol->exps);
+ set_processed(pc);
+ }
+ pc = rel_crossproduct(v->sql->sa, pc,
rel_dup(or), rel->op);
+ pc->exps = exps_copy(v->sql, exps);
+ pc->attr = exps_copy(v->sql, attr);
+ set_processed(pc);
+ pc = rel_project(v->sql->sa, pc,
rel_projections(v->sql, pc, NULL, 1, 1));
+ n->data = pc;
+ }
+ v->changes++;
+ return rel_inplace_setop_n_ary(v->sql, rel, l->l,
op_munion,
+
rel_projections(v->sql, rel, NULL, 1, 1));
+ } else if (is_munion(l->op) && !need_distinct(l) &&
!is_single(l) &&
+ is_munion(r->op) && !need_distinct(r) &&
!is_single(r) &&
+ je) {
+ /* join(munion(a,b,c), union(d,e,f)) ->
munion(join(a,d), join(b,e), join(c,f)) */
+ // TODO
+ } else if (!is_munion(l->op) &&
+ is_munion(r->op) && !need_distinct(r) &&
!is_single(r) &&
+ !is_semi(rel->op)) {
+ /* join(a, munion(b,c,d)) -> munion(join(a,b),
join(a,c), join(a,d)) */
+ // TODO
+ } else if (!is_munion(l->op) &&
+ is_munion(r->op) && !need_distinct(r) &&
!is_single(r) &&
+ is_semi(rel->op) && je) {
+ /* {semi}join ( A1, munion (B, A2, C)) [A1.partkey =
A2.partkey] ->
+ * {semi}join ( A1, A2 )
+ * (ie a single part on n-th munion operand)
+ *
+ * How to detect that a relation isn't matching?
+ * partitioning is currently done only on
pkey/fkey's
+ * ie only matching per part if join is on
pkey/fkey (parts)
+ * and part numbers should match.
+ * */
+ // TODO
+ }
+ }
+ return rel;
+}
+
static sql_rel *
rel_optimize_unions_topdown_(visitor *v, sql_rel *rel)
{
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