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*   CG801.T05 DB-Image Tech Note                         April 1998 *

*                                                                   *

*   KEYWORDS: DB-Image BCF UNLOAD/RELOAD IMAGE SEGMENT              *

*                                                                   *

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* This Tech Note describes the actions that must be taken, should   *

* you wish to Unload/Reload a DB-Image Segment using BCF under IDMS *

* Release 12/14.                                                    *

*                                                                   *

* The two problems that need to be overcome are:                    *

*                                                                   *

* a) The Unload job has to load two copies of the DMCL - old and    *

*    new - even if they are the same. Due to the way the new DMCL   *

*    is loaded, DB-Image does not expand it to include the Image    *

*    Segments and associated control blocks.                        *

* b) Due to the way the Reload job allocates files, DB-Allocate     *

*    does not get control at the correct point to allocate the      *

*    Imaged IDMS Files.                                             *

*                                                                   *

* Follow these instructions exactly, in order to correctly Unload/  *

* Reload a DB-Image Segment.                                        *

*                                                                   *

* 1. Split the Unload/Reload into two distinct jobs, as changes     *

*    are required to the control file passed between the two.       *

* 2. Modify the Unload job's SYSIPT and specify the segment to      *

*    be reloaded into, as the real IDMS base segment name.          *

*    This ensures that IDMSDBL1 will find the segment name when     *

*    it loads the new DMCL - which does not get expanded to         *

*    include the Image Segments.                                    *

*                                                                   *

*    eg. If the IDMS Base Segment is DATASEG1 and the Image Segment *

*        is IMAGSEG1, then your SYSIPT should look something like;  *

*                                                                   *

*           UNLOAD SEGMENT IMAGSEG1                                 *

*           USING SSDATA00                                          *

*           RELOAD INTO DATASEG1                                    *

*           USING SSDATA00                                          *

*           DMCL R120DMCL                                           *

*                                                                   *

*     If you fail to make this change, then you will receive the    *

*     following error on the Unload;                                *

*                                                                   *

*     DB347004 no SSDATA00 Subschema areas map to DMCL R120DMCL     *

*                                                                   *

*  3. You do not require any special parameters in the COXACTL      *

*     file. You should NOT specify UNLD or REORG parameters.        *

*     These are primarily for 10.2, and will cause AMODE problems   *

*     if specified.                                                 *

*  4. Ensure that the Image VSAM files are included in the JCL,     *

*     along with the DB90S install libraries etc.                   *

*  5. Run the Unload. This will unload all records in the Segment/  *

*     Area, using the Imaged pages where found.                     *

*  6. When the Unload has completed, the RELDCTL file that is       *

*     created by the Unload to pass forward to the Reload, has      *

*     to be edited to change the name of the segment to reload      *

*     to, back to the Image Segment Name. The IDMS Segment          *

*     name can clearly be seen between the Subschema name and the   *

*     DMCL name. Change the Segment Name to the Image Segment Name. *

*     For example, using the same names as in the SYSIPT above. The *

*     RELDCTL file would look like this;                            *

*                                                                   *

*    . ..............SSDATA00DATASEG1R120DMCL....................   *

*                            ========                               *

*     This would be edited to;                                      *

*                                                                   *

*    . ..............SSDATA00IMAGSEG1R120DMCL....................   *

*                            ========                               *

*  7. This edited RELDCTL file must be used in the Reload Job.      *

*  8. Create new Image VSAM file(s) to reload the data to.          *

*     Note that these must be initialised as for any normal Image   *

*     VSAM file. Also note that these will probably have a much     *

*     larger number of records than those that were unloaded, as    *

*     they will contain all pages that contained any records for    *

*     the Segment/Area. For example if you are unloading an area    *

*     that has 20,000 pages, and the area is 80% utilised, then     *

*     you will have approximately 16,000 pages written to the new   *

*     Image VSAM file. You should size the new VSAM files           *

*     accordingly.                                                  *

*  9. Add these new Image VSAM files to the Reload JCL.             *

* 10. You must add DD cards to the Reload job that map the Imaged   *

*     IDMS Files to their underlying base files. The DD names of    *

*     the imaged IDMS files are dependant on your FILEMSK           *

*     parameter in the COIMAGE table. If you have not specified     *

*     a FILEMSK in the COIMAGE table, then the default is to        *

*     replace the last two characters of the DDNAME with the new    *

*     Image page group number.                                      *

*                                                                   *

*     For example, if the IDMS DD Statement is;                     *

*         //DATFILEA DD DSN=IDMS.DATA.FILEA,DISP=SHR                *

*                                                                   *

*     and your COIMAGE table entry uses page group 50 for the Image *

*     Page Group, and does not specify a FILEMSK, then the DD       *

*     statement you must add would be;                              *

*         //DATFIL50 DD DSN=IDMS.DATA.FILEA,DISP=SHR                *

*                                                                   *

*     If you do omit specifying an Image DDNAME, you will get the   *

*     message;                                                      *

*                                                                   *

*     IEC130I ddname DD STATEMENT MISSING                           *

*                                                                   *

* 11. Run the reload job. All the unloaded records should now be    *

*     reloaded to the new Image VSAM file(s).                       *

*                                                                   *

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