Bug#16731538 MYSQLD CRITICAL FAILURE DURING ORDERED SELECT FROM NDBINFO.CLUSTER_OPERATIONS

 - The filesort() function asks the handler implementation how many rows are expected
   with estimate_rows_upper_bound(). The default implementation of that function(in handler.h)
    is to return "stats.records+EXTRA_RECORDS" where EXTRA_RECORDS is defined as 10. Unless
   the handler implementation has filled in stats.records it will be 0 and thus 10 will be used for
   calculating size of sort buffer etc.

 - Implement ha_ndbinfo::estimate_rows_upper_bound() to return "many" rows

Author: blaudden

mysql-test/suite/ndb/r/ndbinfo.result

@@ -1336,3 +1336,5 @@ create temporary table old_count
        group by counter_name;
 drop table old_count;
 set @@optimizer_switch=default;
+
+select * from ndbinfo.config_params order by param_number;

mysql-test/suite/ndb/t/ndbinfo.test

@@ -719,4 +719,12 @@ create temporary table old_count
 drop table old_count;
 set @@optimizer_switch=default;
 
+#
+# Bug#16731538 MYSQLD CRITICAL FAILURE DURING ORDERED SELECT FROM NDBINFO.CLUSTER_OPERATIONS
+#  - ha_ndbinfo::estimate_rows_upper_bound() returned 0 rows
+#
+--disable_result_log
+select * from ndbinfo.config_params order by param_number;
+--enable_result_log
+
 --source ndbinfo_drop.inc

sql/ha_ndbinfo.h

@@ -71,6 +71,14 @@ class ha_ndbinfo: public handler
     return HA_CACHE_TBL_NOCACHE;
   }
 
+  virtual ha_rows estimate_rows_upper_bound() {
+    // Estimate "many" rows to be returned so that filesort
+    // allocates buffers properly.
+    // Default impl. for this function is otherwise 10 rows
+    // in case handler hasn't filled in stats.records
+    return HA_POS_ERROR;
+  }
+
 private:
   void unpack_record(uchar *dst_row);