Fix for bug #9798: Rollup crash with InnoDB in setup_sum_funcs().

mysql-test/r/group_min_max.result

@@ -1961,3 +1961,10 @@ a varchar(30), b varchar(30), primary key(a), key(b)
 select distinct a from t1;
 a
 drop table t1;
+create table t1(a int, key(a)) engine=innodb;
+insert into t1 values(1);
+select a, count(a) from t1 group by a with rollup;
+a	count(a)
+1	1
+NULL	1
+drop table t1;

mysql-test/t/group_min_max.test

@@ -610,3 +610,14 @@ create table t1 (
 --enable_warnings
 select distinct a from t1;
 drop table t1;
+
+#
+# Bug #9798: group by with rollup
+#
+
+--disable_warnings
+create table t1(a int, key(a)) engine=innodb;
+--enable_warnings
+insert into t1 values(1);
+select a, count(a) from t1 group by a with rollup;
+drop table t1;

sql/opt_range.cc

@@ -6670,6 +6670,8 @@ cost_group_min_max(TABLE* table, KEY *index_info, uint used_key_parts,
         - NGA = QA - (GA union C) = {NG_1, ..., NG_m} - the ones not in
           GROUP BY and not referenced by MIN/MAX functions.
         with the following properties specified below.
+    B3. If Q has a GROUP BY WITH ROLLUP clause the access method is not 
+        applicable.
 
     SA1. There is at most one attribute in SA referenced by any number of
          MIN and/or MAX functions which, which if present, is denoted as C.
@@ -6754,6 +6756,8 @@ cost_group_min_max(TABLE* table, KEY *index_info, uint used_key_parts,
     other field as in: "select min(a) from t1 group by a" ?
   - We assume that the general correctness of the GROUP-BY query was checked
     before this point. Is this correct, or do we have to check it completely?
+  - Lift the limitation in condition (B3), that is, make this access method 
+    applicable to ROLLUP queries.
 
   RETURN
     If mem_root != NULL
@@ -6793,7 +6797,8 @@ get_best_group_min_max(PARAM *param, SEL_TREE *tree)
     DBUG_RETURN(NULL);        /* This is not a select statement. */
   if ((join->tables != 1) ||  /* The query must reference one table. */
       ((!join->group_list) && /* Neither GROUP BY nor a DISTINCT query. */
-       (!join->select_distinct)))
+       (!join->select_distinct)) ||
+      (thd->lex->select_lex.olap == ROLLUP_TYPE)) /* Check (B3) for ROLLUP */
     DBUG_RETURN(NULL);
   if (table->s->keys == 0)        /* There are no indexes to use. */
     DBUG_RETURN(NULL);