Added comment for ha_statistics::records

sql/handler.h

@@ -851,7 +851,15 @@ public:
   ulonglong max_index_file_length;
   ulonglong delete_length;		/* Free bytes */
   ulonglong auto_increment_value;
-  ha_rows records;			/* Estimated records in table */
+  /*
+    The number of records in the table. 
+      0    - means the table has exactly 0 rows
+    other  - if (table_flags() & HA_STATS_RECORDS_IS_EXACT)
+               the value is the exact number of records in the table
+             else
+               it is an estimate
+  */
+  ha_rows records;
   ha_rows deleted;			/* Deleted records */
   ulong mean_rec_length;		/* physical reclength */
   time_t create_time;			/* When table was created */