Using Presspak compression exit
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Using Presspak compression exit

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Article ID: 17408

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Updated On: 07-09-2024

Products

Datacom Datacom/DB

Issue/Introduction

Sample on how to implement DATPAK compression with the compression exit

Environment

Datacom/DB Presspack 

 

Resolution

Implementation is described in Using Datacom Presspack

There is a practical procedure to follow to implement the exit:

Testing procedure uses sample Database DBID 001 (Human-Resource) and table PMF (Personnel)

  1. Use IVPNEW05 job member from Datacom/DB 15.1 installation which is in INSTJCL library, to:

    1. create a PMF extract dataset which will be used as a backup for step3

    2. create a DCTPMF Presspak module (degree 8) in CUSLIB (DCT=DCTPMF,DEGREE=8,NRECS=200,START=1)

  2. Use DDUPDATE to set the 3150 table transaction 
    //SYSIN DD *
    COMM OPTION=CLOSE,DBID=01
    -USR DATACOM-INSTALL,NEWUSER
    -UPD DATABASE,HUMAN-RESOURCE(PROD,DD,PRIV)
    1000 RESTORE,T006
    -END
    -UPD TABLE,PERSONNEL(T006,DD,PRIV)
    -COM.....1....+....2....+....3....+....4....+....5....+ 
    3150               N                      PRESSPAK DCTPMF
    -END
    -CPY DATABASE,HUMAN-RESOURCE(T006,DD,PRIV),PROD
    -END
    -UPD DATABASE,HUMAN-RESOURCE(PROD,DD,PRIV)
    1000 CATALOG
    -END
    /*
    "Presspak" is in record 3150, Column 43 (compression-exit)
    "DCTPMF" is in column 52 (Encryption-Key)
    "N" is in column 20

    Note:
    For Presspak STRONG compression leave space in column 52
    For Presspak WEAK compression enter WEAK in column 52
    Enter N in column 20 (Y = standard Datacom/DB compression) default is N

  3. Use DBUTLTY to load from Extract taken in step1 
    //SYSIN DD *
    COMM OPTION=CLOSE,DBID=01
    INIT AREA=PMF,DBID=01
    LOAD AREA=PMF,TABLE=PMF,DBID=01,
    FORMAT=EXTRACT,DDNAME=EXTPMF
    COMM OPTION=STATS
    REPORT AREA=CXX,DBID=01
    /*

Sample CXX REPORT extract for table PMF showing User Compression:

TABLE NAME - PMF                                       
OCCURRENCE - PERSONNEL P001                            
TABLE ID   -      2                                    
RECORD LENGTH    -     80 /     92                     
RECORDS IN TABLE -             200                     
LENGTH OF KEY/ELEMENTS -    288                        
NUMBER OF KEYS         -      2                        
NUMBER OF ELEMENTS     -      3                        
CHANGE MASTER KEY    - YES                             
DUPLICATE MASTER KEY - YES                             
RECOVER  - YES   ENCRYPTION - NONE                     
LOGGING  - YES                                         
PIPELINE - YES                                         
DB COMPRESSION   - NO                TRANSITION - NEVER
USER COMPRESSION - YES (PRESSPAK)  (DCTPMF)            
CLUSTER KEY ID     -   0                               
CLUSTER KEY LENGTH -   0                               
                                                       
AUTHID        - SYSUSR                                 
TABLE SQLNAME - PERSONNEL                              
DOMAIN CONSTRAINT - NO                                 
DL1-T CONSTRAINT  - NO                                 
TABLE CONSTRAINED - NO                                 
CURRENT CHECK PENDING - LOAD SET          - NO         
                        RELATED TABLE     - NO         
                        FORWARD RECOVERY  - NO         
TRIGGER(S)        - NO                                 
CURRENT ROW(S) VIOLATE CONSTRAINT(S) - NO              
DATA SET NAME -    .TEST.DATACOM.DBPMF                 

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