MonetDB: Aug2024 - inject extra project when we have expression ...

[Niels Nes via checkin-list]

Changeset: cba1c7d3e8a4 for MonetDB
URL: https://dev.monetdb.org/hg/MonetDB/rev/cba1c7d3e8a4
Modified Files:
        sql/server/rel_optimize_proj.c
Branch: Aug2024
Log Message:

inject extra project when we have expression refering to expressions within the 
same projection, before
pushing expressions down into unions.


diffs (60 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
@@ -1743,6 +1743,18 @@ exps_uses_exp(list *exps, sql_exp *e)
  *                           groupby( c, [gbe], [ count, sum] ) ],
  *                      [gbe], [sum, sum] )
  */
+static inline bool
+rel_has_groupby(sql_rel *r)
+{
+       if (r) {
+               if (is_groupby(r->op))
+                       return true;
+               if (is_simple_project(r->op))
+                       return rel_has_groupby(r->l);
+       }
+       return false;
+}
+
 static inline sql_rel *
 rel_push_aggr_down_n_arry(visitor *v, sql_rel *rel)
 {
@@ -1759,7 +1771,7 @@ rel_push_aggr_down_n_arry(visitor *v, sq
        /* make sure we don't create group by on group by's */
        for (node *n = ((list*)u->l)->h; n; n = n->next) {
                r = n->data;
-               if (r->op == op_groupby)
+               if (rel_has_groupby(r))
                        return rel;
        }
 
@@ -3069,6 +3081,19 @@ bind_optimize_projections(visitor *v, gl
 }
 
 
+static bool
+exps_have_selfref(list *exps)
+{
+       bool selfref = false;
+       if (list_empty(exps))
+               return false;
+       for(node *n = exps->h; n && !selfref; n = n->next) {
+               sql_exp *e = n->data;
+               selfref |= is_selfref(e);
+       }
+       return selfref;
+}
+
 static inline sql_rel *
 rel_push_project_down_union(visitor *v, sql_rel *rel)
 {
@@ -3104,7 +3129,7 @@ rel_push_project_down_union(visitor *v, 
                        r = rel_dup(n->data);
 
                        /* introduce projection around each operand if needed */
-                       if (!is_project(r->op))
+                       if (!is_project(r->op) || exps_have_selfref(r->exps))
                                r = rel_project(v->sql->sa, r,
                                                rel_projections(v->sql, r, 
NULL, 1, 1));
                        /* check if we need distinct */
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