What's the real meaning of DOC_LEN and COMP_LEN ?

[j4jackycheng]

Does anyone knows what's the real meaning of DOC_LEN and COMP_LEN in the Application Group data table?

I have a AFP type document, it says:

Code: [Select]

> db2 "select * from ROOT.DNA39 where invoice_number='493159791'"

ACCOUNT_NUMBER INVOICE_NUMBER INVOICE_RESETS STATEMENT_DATE ACCOUNT_SEGMENT POSTCODE PROCESS_FLAGS                                                    DOC_NAME    DOC_OFF     DOC_LEN     COMP_OFF    COMP_LEN    ANNOT         COMP_TYPE             RESOURCE    PRI_NID SEC_NID
-------------- -------------- -------------- -------------- --------------- -------- ---------------------------------------------------------------- ----------- ----------- ----------- ----------- ----------- ------------- --------------------- ----------- ------- -------
12345678000102 493159791      0                       15453 1               2114     0011                                                             2920FAAB          99109       65955     5641546      208744 x'55'         x'4F'                        1996       1       0

  1 record(s) selected.

And i have a text file:
it says

Code: [Select]

> db2 "select *  from ROOT.KJA1 where REPORT_ID='AB-CD001' and RUN_START_DATE>15463"

REPORT_TITLE                                                 REPORT_ID  DATA_SOURCE          RUN_START_DATE DOC_NAME    DOC_OFF     DOC_LEN     COMP_OFF    COMP_LEN    ANNOT         COMP_TYPE             RESOURCE    PRI_NID SEC_NID
------------------------------------------------------------ ---------- -------------------- -------------- ----------- ----------- ----------- ----------- ----------- ------------- --------------------- ----------- ------- -------
MY SUMMARY REPORT V1.0                                       AB-CD001   ARBOR/BP                      15464 3911FAAA              0    60537551           0     3835640 x'55'         x'4F'                           0       1       0
In the Text file the DOC_LEN is the doucment length (the size in byte of the original document)and the COMP_LEN is the Compression length (the size in byte after compression).
But when i look the the AFP file example, DOC_LEN = 65955 and COMP_LEN = 208744, my question is:

How can the compressed size be greater then the original size?  I tried to search IBM documents for the true meaning of DOC_LEN and COMP_LEN but it doesnt' say much.
Could any one point me to the right direction? THANKS a lot.

[pankaj.puranik]

I found this line below in IBM documentation.
I am not sure but this might be the reason why the compression length is more than the document length.

Compression for AFP documents is based on the output data file produced by ACIF, and not the input file, which could have been line data. When ACIF formats line data with a page definition, it may increase the size of the data by adding AFP controls for positioning text.

[j4jackycheng]

I found this line below in IBM documentation.
I am not sure but this might be the reason why the compression length is more than the document length.

Compression for AFP documents is based on the output data file produced by ACIF, and not the input file, which could have been line data. When ACIF formats line data with a page definition, it may increase the size of the data by adding AFP controls for positioning text.

Thanks Pankaj, i've seen that line too, but don't quite understand    ,  I just want to find a way to accurately calculate the sum(total compressed size) and sum(total original size) from a specific Application Group.