Use the block transfer facility. To use this facility, specify the PDBLKF operand in the client environment definition. A specification value between 40 and 50 is recommended. Specifying a larger value has little effect in reducing the number of communications and instead may delay processing because of the increased processing overhead. For details about the block transfer facility, see 4.7 Block transfer facility.

Use the high-speed connection facility. To use this facility, specify the PDFESHOST, PDSERVICEPORT, and PDSERVICEGRP operands in the client environment definition. The high-speed connection facility shortens the time for connection to HiRDB. For details about the PDFESHOST, PDSERVICEPORT, and PDSERVICEGRP operands of the client environment definition, see 6.6.4 Environment definition information.

If a UAP accesses the HiRDB system via ODBC, the SQL statements specified in the UAP may differ from the SQL statements requested of the HiRDB system, depending on the environment in which the UAP was created. To check what kind of SQL statements are issued to the HiRDB system, use the SQL trace facility. To use this facility, specify the PDSQLTRACE operand in the client environment definition. It is recommended to also specify the trace output destination directory in the PDCLTPATH operand at this time. For details about the SQL trace facility, see 10.1.1 SQL tracing.

• If an application program, such as Microsoft Access, specifies the lock option in a retrieval SQL statement, a syntax error may occur in that application program. If this happens, examine whether the problem can be corrected by specifying the PDISLLVL operand of the client environment definition.
• If you use the Microsoft Jet database engine to access HiRDB, a lock error may occur in HiRDB during updating, depending on how the UAP was created. This occurs when the Microsoft Jet database engine establishes multiple connections to HiRDB and referencing or updating is executed on the same line from different connections. To avoid this, specify 0 or 1 for the PDISLLVL operand in the client environment definition. In the Sampleap directory on the installation floppy disk for the ODBC driver, there is a sample UAP that uses DAO (Data Access Object) of Visual Basic and no lock error occurs during access; refer to this UAP.