Changeset: 6707bb552537 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/6707bb552537
Modified Files:
sql/server/rel_optimize_proj.c
sql/test/miscellaneous/Tests/simple_plans.test
Branch: default
Log Message:
Another corner case. If the underlying projection has to be
sorted/distinct/multiple refs, then the new optimization cannot be done
diffs (93 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
@@ -1444,7 +1444,25 @@ rel_simplify_sum(visitor *v, sql_rel *re
if ((!e1ok && e2ok) || (e1ok && !e2ok))
{
sql_exp *ocol = e1ok ? e2 : e1,
*constant = e1ok ? e1 : e2, *mul, *colref, *naggr, *newop, *col = ocol, *match;
- bool add_col = true;
+ bool add_col = true, prepend =
false;
+
+ /* if 'col' is a projection
from the under relation, then use it */
+ while (is_numeric_upcast(col))
+ col = col->l;
+ if (col->type == e_column) {
+ sql_exp *colf =
exps_find_exp(l->exps, col);
+
+ /* col is already found
in the inner relation. Also look for a new reference for col, eg sql_add(col,
1), 1 as col */
+ if (colf &&
list_position(l->exps, colf) < list_position(l->exps, oexp)) {
+ add_col = false;
+ } else if (!colf &&
is_simple_project(l->op) && list_empty(l->r) && !rel_is_ref(l) &&
!need_distinct(l)) {
+ prepend = true;
+ add_col = false;
+ } else if (!colf &&
(is_simple_project(l->op) || is_groupby(l->op))) {
+ /* on these
scenarios the new column expression will be ordered/(grouped for distinct) or
create potential ambiguity (multiple ref), so skip */
+ continue;
+ }
+ }
/* add count star */
count_star_exp =
rel_groupby_add_count_star(v->sql, groupby, count_star_exp, &count_added);
@@ -1457,20 +1475,6 @@ rel_simplify_sum(visitor *v, sql_rel *re
if (!has_label(mul))
exp_label(v->sql->sa,
mul, ++v->sql->label);
- /* if 'col' is a projection
from the under relation, then use it */
- while (is_numeric_upcast(col))
- col = col->l;
- if (col->type == e_column) {
- sql_exp *colf =
exps_find_exp(l->exps, col);
-
- /* col is already found
in the inner relation. Also look for a new reference for col, eg sql_add(col,
1), 1 as col */
- if (colf &&
list_position(l->exps, colf) < list_position(l->exps, oexp)) {
- add_col = false;
- } else if (!colf &&
is_simple_project(l->op) && list_empty(l->r) && !rel_is_ref(l) &&
!need_distinct(l)) {
-
list_prepend(l->exps, exp_ref(v->sql, col));
- add_col = false;
- }
- }
colref = exp_ref(v->sql, ocol);
if (add_col) /* if 'col' will
be added, then make sure it has an unique label */
exp_label(v->sql->sa,
colref, ++v->sql->label);
@@ -1505,6 +1509,10 @@ rel_simplify_sum(visitor *v, sql_rel *re
continue;
}
+ /* a column reference can be
prepended to the inner relation, add it after all the check type calls succeed
*/
+ if (prepend)
+ list_prepend(l->exps,
exp_ref(v->sql, col));
+
/* the new generate function
calls are valid, update relations */
/* we need a new relation for
the multiplication and addition/subtraction */
if (!upper) {
@@ -1654,6 +1662,9 @@ rel_simplify_groupby_columns(visitor *v,
sql_exp *ne =
exp_ref(v->sql, col);
list_prepend(l->exps,
ne);
n->data =
exp_ref(v->sql, ne);
+ } else if (!colf &&
(is_simple_project(l->op) || is_groupby(l->op))) {
+ /* on these scenarios
the new column expression will be ordered/(grouped for distinct) or create
potential ambiguity (multiple ref), so skip */
+ continue;
} else {
sql_exp *ne =
exp_ref(v->sql, col);
@@ -1713,7 +1724,7 @@ rel_groupby_cse(visitor *v, sql_rel *rel
if (!needed)
return rel;
- if (!is_simple_project(l->op) || !list_empty(l->r) ||
rel_is_ref(l) || need_distinct(l) || is_single(l))
+ if (!is_simple_project(l->op) || !list_empty(l->r) ||
rel_is_ref(l) || need_distinct(l))
rel->l = l = rel_project(v->sql->sa, l,
rel_projections(v->sql, l, NULL, 1, 1));
for (node *n=((list*)rel->r)->h; n ; ) {
diff --git a/sql/test/miscellaneous/Tests/simple_plans.test
b/sql/test/miscellaneous/Tests/simple_plans.test
--- a/sql/test/miscellaneous/Tests/simple_plans.test
+++ b/sql/test/miscellaneous/Tests/simple_plans.test
@@ -701,3 +701,8 @@ SELECT sum(CASE x.x WHEN 1 THEN 1 END +
----
3
3
+
+query I nosort
+SELECT sum(y.y) FROM (SELECT DISTINCT x + 1 FROM (SELECT 1) x(x)) y(y)
+----
+2
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