AJ-758：modify 'parallelism' param default value from '2' to '64';

Author: chengyitian

src/com/xxdb/DBConnection.java

@@ -39,7 +39,7 @@ public class DBConnection {
     private static final int MAX_FORM_VALUE = Entity.DATA_FORM.values().length - 1;
     private static final int MAX_TYPE_VALUE = Entity.DATA_TYPE.DT_DECIMAL128_ARRAY.getValue();
     private static final int DEFAULT_PRIORITY = 4;
-    private static final int DEFAULT_PARALLELISM = 2;
+    private static final int DEFAULT_PARALLELISM = 64;
 
     private ReentrantLock mutex_;
     private DBConnectionImpl conn_;