Performance Considerations

This section lists some special considerations which may help you increase the performance of your Natural for DL/I environment.


Set the DLISIZE parameter to 0 if no DL/I database is to be accessed.

Do not modify NDLPARM parameters, unless requested by a corresponding Natural for DL/I error message. Unused buffers are compressed by the Natural compression algorithm.


Use the same DBID for all segment types (DDMs) of a given NDB, because an OPEN command is generated for each DBID.

Global and Local Data Areas

Keep global and local data areas as small as possible, because the format buffer contains all fields of the global and local data areas, not only those which are referenced by a Natural I/O statement.

FIND Statements

If the sequence field is unique, use a FIND (1) statement instead of a FIND statement to prevent an unnecessary second DL/I call.

Direct Access to Lower Levels

Access segments on lower levels directly (by using the field sequence of the parent); that is, access ancestor segments only if their contents are required by the application program.

In such cases, UDFs of ancestor segments as well as DL/I fields of ancestor segments which are not sequence fields are not available to the application program.

DBLOG Utility

Use the Natural utility DBLOG (TEST DBLOG D) to tune your application; see Logging Database Calls (DBLOG) in the Natural Utilities documentation.