Effects of distributed data on program preparation
In a distributed data environment, several items affect precompile and bind options that are used for DRDA access and package resolution.
The following table lists the z/OS precompiler options that are relevant to preparing a package that is to be run using DRDA access.
| z/OS precompiler options | Usage |
|---|---|
| CONNECT | Use CONNECT(2) to allow your application program to make updates at more than one DBMS. |
| SQL | Use SQL(ALL) for binding a package to a non-z/OS server; otherwise, use SQL(Db2). |
Usually, binding a package to run at a remote location is like binding a package to run at your local Db2 subsystem. Binding a plan to run the package is like binding any other plan. The following table gives you guidelines for which z/OS bind options to choose when binding a package and planning to run using DRDA access.
| z/OS bind options | Usage |
|---|---|
| DEFER(PREPARE) | For dynamic SQL, use DEFER(PREPARE) to send PREPARE and EXECUTE statements together over the network to improve performance. |
| SQLERROR | Use SQLERROR(CONTINUE) to create a package even if the bind process finds SQL errors. |
| SQLRULES | Use SQLRULES(Db2) for more flexibility in coding your applications, particularly for LOB data, and to improve performance. |
JDBC, SQLJ, and ODBC use different methods for binding packages that involve less preparation for accessing a z/OS server.
The CURRENT PACKAGE PATH special register provides a benefit for applications that use DRDA from a z/OS requester. The package collection ID is resolved at the server. Applications on the server can take advantage of the list of collections, and network traffic is minimal.
Example
Assume that five packages exist and that you want to invoke the first package at the server. The package names are SCHEMA1.PKG1, SCHEMA2.PKG2, SCHEMA3.PKG3, SCHEMA4.PKG4, and SCHEMA5.PKG5. Rather than issuing a SET CURRENT PACKAGESET statement to invoke each package, you can use a single SET statement if the server supports the CURRENT PACKAGE PATH special register:
SET CURRENT PACKAGE PATH = SCHEMA1, SCHEMA2, SCHEMA3, SCHEMA4, SCHEMA5;