Special considerations for WLM-managed stored procedures in coexistence

The WLM-managed stored procedure address space (WLM-SPAS) that processes a stored procedure or UDF program always connects to the DB2® member that processes the SQL call request. Therefore, the DB2 code that is executed in the WLM-SPAS must match the DB2 release of the DBM1 address space, or an error occurs.

When running in a data sharing group, each member has a different DBM1 address space. This means that the DB2 code in the WLM-SPAS will have to match more than one DB2 release level. This can cause a problem when you want to use a single JCL definition for the procedure name listed in the WLM definition.

To define one JCL procedure to reference DB2 code data sets at different release levels, use a simple data set and alias naming convention. If the procedure library is shared throughout the SYSPLEX, this allows for a single JCL definition for the Procedure Name that is listed in the WLM definition.

In the following example, the DB2SSN parameter is used as a part of the data set name in STEPLIB. This allows redirection to a data set name based on the SSN of the member that is invoking the stored procedure or UDF.

In the WLM definition:

Application Environment Name . : DB2GROUP1                                
Description  . . . . . . . . . . GROUP 1 APPS                       
Subsystem Type . . . . . . . . . DB2                                     
Procedure Name . . . . . . . . . DB2AWLM1                                
Start Parameters . . . . . . . . DB2SSN=&IWMSSNM                         
                                 ________________________________________

Limit on starting server address spaces for a subsystem instance:        
1   1.  No limit                                                         
    2.  Single address space per system                                  
    3.  Single address space per Sysplex

The special keyword &IWMSSNM in the WLM definition causes WLM to send the subsystem name as the DB2SSN parm when the address space is started. In the WLM-SPAS JCL:

//DB2AWLM1 PROC RGN=0M,DB2SSN=,NUMTCB=1,APPLENV=DB2GROUP1  
//IEFPROC EXEC PGM=DSNX9WLM,REGION=&RGN,TIME=NOLIMIT,    
//        PARM='&DB2SSN,&NUMTCB,&APPLENV'                
//STEPLIB  DD  DISP=SHR,DSN=DSNT2.&DB2SSN..SDSNEXIT      
//         DD  DISP=SHR,DSN=DSNT2.&DB2SSN..SDSNLOAD      
//         DD  DISP=SHR,DSN=DSNT2.&DB2SSN..SDSNLOD2      
//         DD  DISP=SHR,DSN=DSNT2.RUNLIB.LOAD

If one subsystem name is DT21 then the following alias can be used to redirect the library name to a release-specific library for that member. This would allow you to have a single release-specific library for a data sharing group.

DSNT2.DT21.SDSNLOAD                                            *ALIAS

As members are migrated, the ALIAS can be changed to reflect the new release that the member is running.