Version 8.1.4
 —  Utilities  —

COMPRESS Function Output

This document describes the ADACMP COMPRESS function output.


Compressed Data Records

The data records that ADACMP has processed, edited, and compressed are written out together with the file definition information to a sequential data set with the variable blocked record format. This data set may be used as input to the ADALOD utility. The output of several ADACMP executions may also be used as input to ADALOD.

If the output data set contains no records (no records provided on the input data set or all records rejected), the output may still be used as input to the ADALOD utility. In this case, you must ensure that the amount of Associator space allocated to the file is sufficient since an accurate estimate cannot be made by the ADALOD utility without a representative sample of input record values (see the ADALOD utility for additional information).

For information on how to identify MU and PE occurrences greater than 191 in the compressed record, read Identifying MU and PE Occurrences Greater Than 191 in Compressed Records.

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Rejected Data Records

Any records rejected during ADACMP compression are written to the DD/FEHL error data set. The records are output in variable blocked format and may be segmented into multiple physical records. Each logical rejected record will be preceded by an initial ADAF rejected record header. If the logical record and the ADAF header do not fit in the DD/FEHL physical record length, ADAN rejected record headers will precede the remaining physical rejected record segments that comprise the logical rejected record.

The functions of these two different headers are as follows:

DSECTs for the ADAF and ADAN headers can be found in members ADAF and ADAN of the distributed Adabas SRCE data set.

Traditionally, the DD/FEHL error data set produced for ADACMP errors has truncated rejected records that exceeded the FEHL physical record length. In Version 8, the rejected records are segmented instead of truncated. Because of this change, the DD/FEHL LRECL setting must be at least 500 bytes.

If HEADER=YES is specified, an error may occur while segmented uncompressed records are being assembled into a logical record. If the ADAH header is in error, the ADAH record is written and subsequent ADAC records are not written until the next ADAH record is processed. If an ADAC header is in error, the preceding ADAH header will be written without its payload data. The ADAC record in error will be written in its entirety. Subsequent ADAC records are not written until the next ADAH record is processed.

The following response codes may occur:

X'E7'(231) Input record too short (COMPRESS)
X'E8'(232) Output record length error (COMPRESS)
X'E9'(233) An invalid ADAH spanned record header has been encountered. The following subcodes provide more detail:
  • 1 - incorrect ADAH eye-catcher

  • 2 - incorrect ADAH header length

  • 3 - unexpected continuation indicator

  • 4 - reserved area not set to binary zeros

  • 5 - invalid segment length

  • 6 - total payload data length exceeds MAXLOGRECLEN setting

For complete information about spanned records and the ADAH header, read Spanned Records. The DSECT for the ADAH header can be found in member ADAH of the distributed Adabas SRCE data set.

X'EA'(234) An invalid ADAC spanned record header has been encountered. The following subcodes provide more detail:
  • 1 - incorrect ADAC eye-catcher

  • 2 - incorrect ADAC header length

  • 3 - unexpected continuation indicator

  • 4 - reserved area not set to binary zeros

  • 5 - invalid segment length

  • 6 - unexpected continuation record sequence number

  • 7 - invalid segment offset

  • 8 - accumulated payload data length exceeds specified total length in ADAH

  • 9 - accumulated payload data length exceeds MAXLOGRECLEN setting

For complete information about spanned records and the ADAC header, read Spanned Records. The DSECT for the ADAC header can be found in member ADAC of the distributed Adabas SRCE data set.

Only the first incorrect field within a record is detected and referenced. If there are other errors, they are not detected until subsequent runs are made.

Example of Rejected Data Records

The following table depicts the FEHL output for four rejected records during ADACMP compression. Rejected records 1 and 3 have only one FEHL record (ADAF); rejected record 2 is segmented into two FEHL records (ADAF and ADAN); rejected record 4 is segmented into three FEHL records (one ADAF record and two ADAN records):

Note:
DSECTs for the ADAF and ADAN headers can be found in members ADAF and ADAN of the distributed Adabas SRCE data set.

Rejected Record FEHL Records FEHL Fields Description
Field Value
1 ADAF ADAFEYE ADAF ADAF header eye-catcher
ADAFLEN 72 ADAF header length
ADAFTYPE R Type. Valid values are:

H: ADAH header
P: ADAH header and payload
R: Logical record

ADAFIND E Continuation indicator. Valid values are:

C: Continuation record to follow
E: End of logical record (last segment)

Reserved 0 Reserved
ADAFSLEN 22000 Segment length (length of payload data following the header)
ADAFTOTL 22000 Total length.

Note:
The sum of the values of all ADANSLEN fields and ADAFSLEN should equal the value of ADAFTOTL (for record 1 in this example, 0 + 22000 = 22000)

ADAFISN 1 ISN of record
ADAFLNUM 1 Logical record number
ADAFPNUM 1 Physical record number
ADAFEOFF 5000 Error offset in logical record
ADAFPEX 0 PE index
ADAFFN ZA Field name
ADAFRSP 41 Response code
ADAFSUB 2 Subcode
Reserved 0 Reserved
ADAFDATA 'Record 1 -- Payload Data' Rejected input data
2 ADAF ADAFEYE ADAF ADAF header eye-catcher
ADAFLEN 72 ADAF header length
ADAFTYPE R Type. Valid values are:

H: ADAH header
P: ADAH header and payload
R: Logical record

ADAFIND C Continuation indicator. Valid values are:

C: Continuation record (ADAN) to follow
E: End of logical record (last segment)

Reserved 0 Reserved
ADAFSLEN 27962 Segment length (length of payload data following the header)
ADAFTOTL 50000 Total length.

Note:
The sum of the values of all ADANSLEN fields and ADAFSLEN should equal the value of ADAFTOTL (for record 2 in this example, 22038 + 27962 = 50000)

ADAFISN 2 ISN of record
ADAFLNUM 2 Logical record number
ADAFPNUM 3 Physical record number
ADAFEOFF 35000 Error offset in logical record
ADAFPEX 0 PE index
ADAFFN ZA Field name
ADAFRSP 41 Response code
ADAFSUB 2 Subcode
Reserved 0 Reserved
ADAFDATA 'Record 2 -- Payload data part 1' Rejected input data
ADAN ADANEYE ADAN ADAN header eye-catcher
ADANLEN 24 ADAN header length
ADANTYPE R Type. Valid values are:

C: ADAC header
D: ADAC header and payload
P: ADAH record segment
R: Logical record segment

ADANIND E Continuation indicator. Valid values are:

C: Continuation record (ADAN) to follow
E: End of logical record (last segment)

Reserved 0 Reserved
ADANSLEN 22038 Segment length (length of payload data following the header)
ADANOFF 27962 Error offset in logical record.
ADANDATA 'Record 2 -- Payload data part 2' Continued rejected input data
3 ADAF ADAFEYE ADAF ADAF header eye-catcher
ADAFLEN 72 ADAF header length
ADAFTYPE P Type. Valid values are:

H: ADAH header
P: ADAH header and payload
R: Logical record

ADAFIND E Continuation indicator. Valid values are:

C: Continuation record (ADAN) to follow
E: End of logical record (last segment)

Reserved 0 Reserved
ADAFSLEN 20000 Segment length (length of payload data following the header)
ADAFTOTL 20000 Total length.

Note:
The sum of the values of all ADANSLEN fields and ADAFSLEN should equal the value of ADAFTOTL (for record 3 in this example, 0 + 20000 = 20000)

ADAFISN 3 ISN of record
ADAFLNUM 3 Logical record number
ADAFPNUM 4 Physical record number
ADAFEOFF 0 Error offset in logical record
ADAFPEX 0 PE index
ADAFFN   Field name
ADAFRSP 233 Response Code
ADAFSUB 1 Subcode
Reserved 0 Reserved
ADAFDATA ADAH and payload data Rejected input data
4 ADAF ADAFEYE ADAF ADAF header eye-catcher
ADAFLEN 72 ADAF header length
ADAFTYPE H Type. Valid values are:

H: ADAH header
P: ADAH header and payload
R: Logical record

ADAFIND C Continuation indicator. Valid values are:

C: Continuation record (ADAN) to follow
E: End of logical record (last segment)

Reserved 0 Reserved
ADAFSLEN 32 Segment length (length of payload data following the header)
ADAFTOTL 10064 Total length.

Note:
The sum of the values of all ADANSLEN fields and ADAFSLEN should equal the value of ADAFTOTL (for record 4 in this example, 32 + 32 + 10000 = 10064)

ADAFISN 4 ISN of record
ADAFLNUM 4 Logical record number
ADAFPNUM 8 Physical record number
ADAFEOFF 0 Error offset in logical record
ADAFPEX 0 PE index
ADAFFN   Field name
ADAFRSP 234 Response Code
ADAFSUB 3 Subcode
Reserved 0 Reserved
ADAFDATA ADAH header Rejected input data
ADAN ADANEYE ADAN ADAN header eye-catcher
ADANLEN 24 ADAN header length
ADANTYPE C Type. Valid values are:

C: ADAC header
D: ADAC header and payload
P: ADAH record segment
R: Logical record segment

ADANIND C Continuation indicator. Valid values are:

C: Continuation record (ADAN) to follow
E: End of logical record (last segment)

Reserved 0 Reserved
ADANSLEN 32 Segment length (length of payload data following the header)
ADANOFF 32 Error offset in logical record.
ADANDATA ADAC header Continued rejected input data
ADAN ADANEYE ADAN ADAN header eye-catcher
ADANLEN 24 ADAN header length
ADANTYPE D Type. Valid values are:

C: ADAC header
D: ADAC header and payload
P: ADAH record segment
R: Logical record segment

ADANIND E Continuation indicator. Valid values are:

C: Continuation record (ADAN) to follow
E: End of logical record (last segment)

Reserved 0 Reserved
ADANSLEN 10000 Segment length (length of payload data following the header)
ADANOFF 64 Error offset in logical record.
ADANDATA ADAC and payload data Continued rejected input data

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ADACMP Report

ADACMP calculates the approximate amount of space (in both blocks and cylinders) required for Data Storage for the compressed records. This information is printed as a matrix which contains the required space for the different device types requested by the DEVICE parameter for various Data Storage padding factors between 5 and 30 percent.

The following is an example of ADACMP report output:

PARAMETERS:
   
ADACMP COMPRESS NUMREC=1000
ADACMP FNDEF='01,AA,8,B,DE'
ADACMP FNDEF='01,BA,6,A,NU'
ADACMP FNDEF='01,BB,8,P,NU'
ADACMP FNDEF='01,AD,1,A,FI'
ADACMP SUBDE='CA=BA(1,3)'

COMPRESS PROCESSING STATISTICS:

NUMBER OF RECORDS READ                1,000
NUMBER OF INCORRECT RECORDS               0
NUMBER OF COMPRESSED RECORDS          1,000

RAW DATA                             24,000 BYTES
COMPRESSED DATA                      16,656 BYTES
COMPRESSION RATE                       31.9 %
LARGEST COMPRESSED RECORD                20 BYTES


DATASTORAGE SPACE REQUIREMENTS:

I  DEVICE  I  PADDING I  BLOCKSIZE I          NUMBER OF     I
I          I  FACTOR  I    BYTES   I      BLOCKS      CYLS  I
I----------I----------I------------I------------------------I
I   3380   I          I    4,820   I                        I
I          I     5%   I    4,578   I           4         1  I
I          I    10%   I    4,337   I           4         1  I
I          I    15%   I    4,096   I           5         1  I
I          I    20%   I    3,856   I           5         1  I
I          I    25%   I    3,615   I           5         1  I
I          I    30%   I    3,373   I           5         1  I
I          I          I            I                        I
I----------I----------I------------I------------------------I

TEMP SPACE ESTIMATION:

I  DEVICE  I  BLOCKSIZE I          NUMBER OF     I
I          I    BYTES   I      BLOCKS      CYLS  I
I----------I------------I------------------------I
I   3380   I    7,476   I           5          1 I
I----------I------------I------------------------I

THE LARGEST DESCRIPTOR IS AA, IT WILL OCCUPY 1 TEMP BLOCKS


SORT SPACE ESTIMATION:

I DEVICE I BLOCKSIZE I   LWP              I      NR OF      I
I        I  (BYTES)  I  (BYTES)           I  BLOCKS    CYLS I
-------------------------------------------------------------
I  3380  I     7476  I   139264 (MINIMUM) I       2       1 I
I        I           I  1048576 (DEFAULT) I       2       1 I
I        I           I   139264 (OPTIMUM) I       2       1 I
I--------I-----------I--------------------I-----------------I

The compression rate is computed based on the real amount of data used as input to the compression routine. Fields skipped by a format element "nX" (used to fill a field with blanks) are not counted.

If SPAN was specified in an ADACMP COMPRESS run, statistics about the spanned Data Storage records are also printed:

Spanned Record Statistics:                    
--------------------------                    
                                              
Number of Non-Spanned records               2 
Number of Spanned records                   8 
Min Number of Segments              2         
Max Number of Segments              5         
Avg Number of Segments              4         
                                              
Max MU Count                        0         
Max PE Count                      300         

If large object (LB) fields are compressed, statistics about the LB fields (listed as "LOBs" in the report) are printed:

Large Objects Statistics:                           
--------------------------                          
                                                    
Number of bytes for largest LOB           10,124,996
Total number of LOBs                                         5
Total number of outsourced LOBs                        5
Number of LOB file records                         10,085

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