Specifying the default application compatibility level

The APPLCOMPAT subsystem parameter specifies the default value of the APPLCOMPAT bind option. It must be set to a value that is equivalent to or lower than the activated function level. Its value does not prevent specific applications from using higher APPLCOMPAT levels.

Before you begin

  1. Start of changeActivate function level 500 or higher, as described in Activating Db2 12 new function at migration.End of change
  2. For any packages that need to continue running at a lower level, bind or rebind them and explicitly specify the APPLCOMPAT bind option. For more information, see Controlling the Db2 application compatibility level.
  3. Start of changeTake the following precautions to ensure that applications are ready to run at the higher application compatibility level by default.End of change
    • Identify and resolve all application incompatibilities of the higher level, as described in Managing incompatible changes for applications.
    • Rebind any packages that must continue to run at the lower application compatibility level and explicitly specify the APPLCOMPAT bind option for that level.

About this task

After all applications are ready to run at a higher application compatibility level or explicitly bound at a lower level, you can increase the APPLCOMPAT subsystem parameter value to bind packages at a higher application compatibility level by default.

The APPLCOMPAT subsystem parameter specifies the default value to use when the APPLCOMPAT bind option is not specified in a BIND command, or the APPLCOMPAT value is not specified or stored in the Db2 catalog for a REBIND command. Its value does not prevent specific applications from running at higher application compatibility levels. For more information, see APPL COMPAT LEVEL field (APPLCOMPAT subsystem parameter).

Procedure

Start of changeTo enable default application compatibility with the current function level:End of change

  1. Start of changeChange the APPLCOMPAT subsystem parameter setting. Start of changeSet the value to V12R1M500 or the equivalent higher active function-level value.End of changeEnd of change
    You can complete this step as described in Updating subsystem parameter and application default values, or by modifying your customized copy of the DSNTIJUZ job.
    The format is VvvRrMmmm, where vv is the version, r is the release, and mmm is the modification level. For example, V12R1M510 identifies function level 510. For a list of all available function levels in Db2 12, see Db2 12 function levels. See the activation details for each function level for a summary the new features that are controlled by the corresponding application compatibility level.
  2. Run the first two job steps of DSNTIJUZ to rebuild your subsystem parameter (DSNZPxxx) module.
  3. Use the -SET SYSPARM command or restart Db2.

Results

Future bind and rebind operations set the application compatibility level of the package to the APPLCOMPAT subsystem parameter value, if the APPLCOMPAT bind option is not specified. Packages that are bound or rebound at the higher level can begin use of SQL capabilities introduced at that level.