Changeset: 6b15ba846e29 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/6b15ba846e29
Modified Files:
sql/server/rel_optimizer.c
Branch: balanced_union
Log Message:
First impl of balanced union rewrite
diffs (112 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
@@ -70,6 +70,55 @@ typedef struct {
} merge_table_prune_info;
static sql_rel *
+rel_wrap_select_around_table(visitor *v, sql_rel *t, merge_table_prune_info
*info)
+{
+ // TODO: it has to be a table (merge table component) add checks
+ sql_table *subt = (sql_table *)t->l;
+
+ if (isMergeTable(subt)) {
+ // TODO: handle it
+ return NULL;
+ }
+
+ if (info) {
+ t = rel_select(v->sql->sa, t, NULL);
+ t->exps = exps_copy(v->sql, info->sel->exps);
+ set_processed(t);
+ set_processed(t);
+ }
+ return t;
+}
+
+static sql_rel *
+rel_unionize_mt_tables_balanced(visitor *v, sql_rel* mt, list* tables,
merge_table_prune_info *info)
+{
+ /* This function is creating the union tree in the tables list calling
+ * itself recursively until the tables list has a single entry (the
union tree)
+ */
+
+ /* base case */
+ if (tables->cnt == 1) // XXX: or/and h->next == NULL
+ return tables->h->data;
+ /* merge (via union) every *two* consequtive nodes of the list */
+ for (node *n = tables->h; n && n->next; n = n->next->next) {
+ /* first (left) node */
+ sql_rel *tl = rel_wrap_select_around_table(v, n->data, info);
+ /* second (right) node */
+ sql_rel *tr = rel_wrap_select_around_table(v, n->next->data,
info);
+ /* create the union */
+ sql_rel *tu = rel_setop(v->sql->sa, tl, tr, op_union);
+ rel_setop_set_exps(v->sql, tu, rel_projections(v->sql, mt,
NULL, 1, 1), true);
+ set_processed(tu);
+ /* replace the two nodes with the new relation */
+ list_append_before(tables, n, tu);
+ list_remove_node(tables, NULL, n);
+ list_remove_node(tables, NULL, n->next);
+ // TODO: do i need to rebuild the hash of the list?
+ }
+ return rel_unionize_mt_tables_balanced(v, mt, tables, info);
+}
+
+static sql_rel *
merge_table_prune_and_unionize(visitor *v, sql_rel *mt_rel,
merge_table_prune_info *info)
{
if (mvc_highwater(v->sql))
@@ -363,25 +412,35 @@ merge_table_prune_and_unionize(visitor *
}
nrel = rel_project(v->sql->sa, nrel, converted);
} else { /* Unionize children tables */
- for (node *n = tables->h; n ; n = n->next) {
- sql_rel *next = n->data;
- sql_table *subt = (sql_table *) next->l;
+
+ if (mvc_debug_on(v->sql, 16)) {
+ /* In case of a single table there in nothing to
unionize */
+ if (tables->cnt == 1) {
+ nrel = rel_wrap_select_around_table(v,
tables->h->data, info);
+ } else {
+ nrel = rel_unionize_mt_tables_balanced(v,
mt_rel, tables, info);
+ }
+ } else {
+ for (node *n = tables->h; n ; n = n->next) {
+ sql_rel *next = n->data;
+ sql_table *subt = (sql_table *) next->l;
- if (isMergeTable(subt)) { /* apply select predicate
recursively for nested merge tables */
- if (!(next = merge_table_prune_and_unionize(v,
next, info)))
- return NULL;
- } else if (info) { /* propagate select under union */
- next = rel_select(v->sql->sa, next, NULL);
- next->exps = exps_copy(v->sql, info->sel->exps);
- set_processed(next);
- }
+ if (isMergeTable(subt)) { /* apply select
predicate recursively for nested merge tables */
+ if (!(next =
merge_table_prune_and_unionize(v, next, info)))
+ return NULL;
+ } else if (info) { /* propagate select under
union */
+ next = rel_select(v->sql->sa, next,
NULL);
+ next->exps = exps_copy(v->sql,
info->sel->exps);
+ set_processed(next);
+ }
- if (nrel) {
- nrel = rel_setop(v->sql->sa, nrel, next,
op_union);
- rel_setop_set_exps(v->sql, nrel,
rel_projections(v->sql, mt_rel, NULL, 1, 1), true);
- set_processed(nrel);
- } else {
- nrel = next;
+ if (nrel) {
+ nrel = rel_setop(v->sql->sa, nrel,
next, op_union);
+ rel_setop_set_exps(v->sql, nrel,
rel_projections(v->sql, mt_rel, NULL, 1, 1), true);
+ set_processed(nrel);
+ } else {
+ nrel = next;
+ }
}
}
}
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