Always report row type of 'Fixed' for MEMORY tables. (Bug #3094)

mysql-test/r/heap.result:
  Add new results
mysql-test/t/heap.test:
  Add new regression test
sql/ha_heap.h:
  Always report row type of Fixed for MEMORY tables

mysql-test/r/heap.result

@@ -701,3 +701,10 @@ insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd
 insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyz");
 ERROR 23000: Duplicate entry 'abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcdefghijkl' for key 1
 drop table t1;
+create table t1 (c char(10)) engine=memory;
+create table t2 (c varchar(10)) engine=memory;
+show table status like 't_';
+Name	Engine	Version	Row_format	Rows	Avg_row_length	Data_length	Max_data_length	Index_length	Data_free	Auto_increment	Create_time	Update_time	Check_time	Collation	Checksum	Create_options	Comment
+t1	MEMORY	10	Fixed	0	11	0	720192	0	0	NULL	NULL	NULL	NULL	latin1_swedish_ci	NULL		
+t2	MEMORY	10	Fixed	0	12	0	785664	0	0	NULL	NULL	NULL	NULL	latin1_swedish_ci	NULL		
+drop table t1, t2;

mysql-test/t/heap.test

@@ -437,3 +437,13 @@ insert into t1 values ("abcdefghijklmnopqrstuvwxyzabcdefghijklmnopqrstuvwxyzabcd
 drop table t1;
 
 # End of 4.1 tests
+
+#
+# Bug #3094: Row format of memory tables should always be reported as Fixed
+#
+create table t1 (c char(10)) engine=memory;
+create table t2 (c varchar(10)) engine=memory;
+show table status like 't_';
+drop table t1, t2;
+
+# End of 5.0 tests

sql/ha_heap.h

@@ -43,6 +43,8 @@ public:
     return ((table->key_info[inx].algorithm == HA_KEY_ALG_BTREE) ? "BTREE" :
 	    "HASH");
   }
+  /* Rows also use a fixed-size format */
+  enum row_type get_row_type() const { return ROW_TYPE_FIXED; }
   const char **bas_ext() const;
   ulong table_flags() const
   {