Changing the Size of a BCS

You can change the size of a catalog if the catalog is much larger than necessary, or if it has grown into excessive secondary extents. Before changing the size of a catalog, consider merging small catalogs or splitting large catalogs.

When you change the size of a catalog, the catalog is also reorganized.

If you are decreasing the size of the catalog, you must be certain to define the new catalog with enough space to contain all the entries in the existing catalog. The catalog must also account for the free space defined for the catalog.

Before changing any catalog always:

Ensure you have a good backup of a valid catalog. Using IDCAMS DIAGNOSE and EXAMINE on the catalog and correcting any errors before taking the backup will ensure you can fall back to a valid backup if there are problems. Having more than one copy is always a good idea in case one copy becomes damaged or lost. This backup can be a full volume dump of the volume the catalog is on, a DFDSS backup or IDCAMS EXPORT. Having all three gives you more options if you need to back out of the catalog changes.
Use IDCAMS DIAGNOSE and EXAMINE to ensure that the catalog does not have errors.
Consider using IDCAMS LISTCAT ALL on the catalog to be changed, in case there are problems. Because this may produce a large volume of output you may wish to redirect the output to a data set, either by pointing the SYSPRINT DD statement to a data set or by using the OFILE keyword on the LISTCAT command.
If you are changing a catalog that is shared across systems, a LISTCAT of the master catalog with the ALL keyword is needed to enable a redefine of any aliases that point to the user catalog that is being changed, unless you already have a job set up to define the aliases. If you already have a job, verify that it is current by comparing the LISTCAT output to the job.
Quiesce all activity against the catalog that is to be changed.

Run the following commands as the first part of the change process and, if there are errors, make the required corrections before proceeding with changing the catalog.

//DIAGNOSE EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=*
//DIAGDD   DD   DISP=SHR,DSN=your.user.catalog
//SYSIN    DD   *
  DIAGNOSE ICFCATALOG INFILE(DIAGDD)
//EXAMINE1 EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=*
//SYSIN    DD   *
  EXAMINE NAME(your.user.catalog) -
    INDEXTEST NODATATEST ERRORLIMIT(1000)
//EXAMINE2 EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=*
//SYSIN    DD   *
  EXAMINE NAME(your.user.catalog) -
    NOINDEXTEST DATATEST ERRORLIMIT(1000)
//LISTCAT  EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=*
//SYSIN    DD   *
  LISTCAT CAT(your.user.catalog) ALL

The following steps show how to change the size of a catalog. The catalog used in the example is called ICFCAT.USER.VSYS303.

Lock the catalog.

//LOCKCAT EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN    DD *
   ALTER ICFCAT.USER.VSYS303 LOCK
/*

Issue the following command on each system that shares the catalog:
```
F CATALOG,NOVLF(ICFCAT.USER.VSYS303)
```
If the catalog is shared with other systems and those other systems do not all share the same master catalog, then EXPORT DISCONNECT the catalog on all other systems other than the system you are running the jobs to resize the catalog on.
```
//EXPDISC  EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=*
//SYSIN    DD *
           EXPORT ICFCAT.USER.VSYS303 DISCONNECT
```
Export the BCS with the EXPORT command. The aliases of the catalog are saved with the exported copy, and can be used in later steps to redefine the aliases. You must create a sequential data set for the catalog export, if one does not already exist.
```
//EXPORT  EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//EXPDD    DD DSN=CATBACK.ICFCAT.USER.VSYS303,DISP=OLD
//SYSIN    DD *
   EXPORT ICFCAT.USER.VSYS303 -
       OUTFILE(EXPDD) -
       TEMPORARY
/*
```

Delete the BCS with the RECOVERY option.

//DELCAT  EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN    DD *
  DELETE ICFCAT.USER.VSYS303 -
       RECOVERY -
       USERCATALOG
/*

Redefine the BCS with the desired space and performance attributes.

//DFNEWCAT EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN    DD *
    DEFINE USERCATALOG -
          (NAME(ICFCAT.USER.VSYS303) -
           VOLUME(SYS303) -
           MEGABYTES(15 5) -
           ICFCATALOG -
           LOCK -
           FREESPACE(20 20) -
           STRNO(3)  -
           )  -
           DATA( CONTROLINTERVALSIZE(4096) -
                 BUFND(4)  )  -
           INDEX( CONTROLINTERVALSIZE(4096) -

                     BUFNI(4)  )
/*

Import the BCS using the IMPORT command. Specify INTOEMPTY on the IMPORT command.

Also, specify ALIAS, so that the aliases exported with the catalog are redefined.

//IMPORT  EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN    DD *
    IMPORT INDATASET(CATBACK.ICFCAT.USER.VSYS303) -
           OUTDATASET(ICFCAT.USER.VSYS303)        -
           ALIAS   -
           LOCK  -
           INTOEMPTY
/*

If the catalog is shared with other systems that do not share the same master catalog then you will need to IMPORT CONNECT on all other systems that share the catalog.

//IMPRTCON EXEC PGM=IDCAMS
//SYSPRINT DD  SYSOUT=*
//SYSIN    DD  *
        IMPORT CONNECT -
            OBJECTS((ICFCAT.USER.VSYS303) -
            DEVICETYPE(3390) -
            VOLUMES(SYS303)))

If the catalog is shared with other systems that do not share the same master catalog then you will need to define the aliases for that catalog on the other systems that do not share the same master catalog.

Run the following commands and, if there are any errors, make the required corrections before unlocking the catalog.

//DIAGNOSE EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=*
//DIAGDD   DD   DISP=SHR,DSN=your.user.catalog
//SYSIN    DD   *
  DIAGNOSE ICFCATALOG INFILE(DIAGDD)
//EXAMINE1 EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=*
//SYSIN    DD   *
  EXAMINE NAME(your.user.catalog) -
    INDEXTEST NODATATEST ERRORLIMIT(1000)
//EXAMINE2 EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=*
//SYSIN    DD   *
  EXAMINE NAME(your.user.catalog) -
  NOINDEXTEST DATATEST ERRORLIMIT(1000)
//LISTCAT  EXEC PGM=IDCAMS
//SYSPRINT DD   SYSOUT=*
//SYSIN    DD   *
  LISTCAT CAT(your.user.catalog) ALL
.

If there were no errors in the previous step , you can now unlock the catalog:

//LOCKCAT EXEC PGM=IDCAMS
//SYSPRINT DD SYSOUT=A
//SYSIN    DD *
    ALTER ICFCAT.USER.VSYS303 UNLOCK
/*