Sequential Subset Statistics report

The Sequential Subset Statistics report contains statistics that are useful in determining how much relative space in the root addressable area needs to be allocated to each subset.

The following two figures show examples of Sequential Subset Statistics reports.

Figure 1. Sequential Subset Statistics report (IDTYPE=C)
IMS HIGH PERFORMANCE UNLOAD - SSR                           "SEQUENTIAL SUBSET STATISTICS"                               PAGE:     1
5655-E06                                                   DATE: 06/01/2021  TIME: 11.26.15                         FABISTAT - V1.R2

SUBSET NBR    NBR OF ROOTS      NBR OF BYTES     SUBSET-ID
----------    ------------      ------------     ---------
1                    2,026             3,500     10000
2                    1,030             4,280     12000
3                        0                 0     14000
4                        0                 0     16000
5                        0                 0     18000
6                    1,003             1,400     20000
7                        0                 0     22000
8                        0                 0     24000
9                    2,005               620     26000
10                   1,018               310     30000

IMS HIGH PERFORMANCE UNLOAD - SSR                           "SEQUENTIAL SUBSET STATISTICS"                               PAGE:     2
5655-E06                                                   DATE: 06/01/2021  TIME: 11.26.15                         FABISTAT - V1.R2

SUBSET NBR      % OF ROOTS        % OF BYTES     SUBSET-ID
----------      ----------        ----------     ---------
1                    28.58             34.61     10000
2                    14.30             42.33     12000
3                     0.00              0.00     14000
4                     0.00              0.00     16000
5                     0.00              0.00     18000
6                    14.26             13.84     20000
7                     0.00              0.00     22000
8                     0.00              0.00     24000
9                    28.56              6.13     26000
10                   14.28              3.06     30000




NBR OF ORPHANS=              121  

DBDNAME   =SSRHDBD3
RANDOMIZER=SSRANDC2
Figure 2. Sequential Subset Statistics report (IDTYPE=X)
IMS HIGH PERFORMANCE UNLOAD - SSR                           "SEQUENTIAL SUBSET STATISTICS"                               PAGE:     1
5655-E06                                                   DATE: 06/01/2021  TIME: 10.06.31                         FABISTAT - V1.R2

SUBSET NBR    NBR OF ROOTS      NBR OF BYTES     SUBSET-ID
----------    ------------      ------------     ---------
1                       30            15,645     EED00000FFFF
                                                 22D010000001
2                      121            62,990     EED00000FFFF
                                                 22D020000002
3                       19            15,642     EED00000FFFF
                                                 22D030000003
4                      345           179,760     EED00000FFFF
                                                 22D040000004
5                       83            43,226     EED00000FFFF
                                                 22D050000005

IMS HIGH PERFORMANCE UNLOAD - SSR                           "SEQUENTIAL SUBSET STATISTICS"                               PAGE:     2
5655-E06                                                   DATE: 06/01/2021  TIME: 10.06.31                         FABISTAT - V1.R2

SUBSET NBR      % OF ROOTS        % OF BYTES     SUBSET-ID
----------      ----------        ----------     ---------
1                     5.02              4.93     EED00000FFFF
                                                 22D010000001
2                    20.23             19.85     EED00000FFFF
                                                 22D020000002
3                     3.18              4.93     EED00000FFFF
                                                 22D030000003
4                    57.69             56.66     EED00000FFFF
                                                 22D040000004
5                    13.88             13.62     EED00000FFFF
                                                 22D050000005



NBR OF ORPHANS=              154  

DBDNAME   =SSRHDBD4
RANDOMIZER=SSRANDX2
Note: When IDTYPE=X is specified on the FABITAB macro statement as input for the generation of the Sequential Subset Randomizer, the values in the subset ID fields are described as hexadecimal values using two lines. For example, the subset-ID values for FKD1 are described as follows: 
            EED....
            22D.... .

These values are X' E2', X'E2', and X'DD'.

The SS-STATS routine prints a table containing one table entry for each subset with the following information on the HSSRSTAT data set:

  • The relative subset number.
  • The number of database roots in the subset.
  • The total number of data bytes and prefix bytes in all database segments that belong to the subset.
    Notes:
    • This number includes only database segments of the first data set group.
    • If segments are compressed, this number reflects the data length of the compressed segments (when stored on DASD).
    • The length of segment prefixes is included in this figure.
  • The first 83 bytes of the subset ID value printed in EBCDIC or in hexadecimal according to the value of IDTYPE= keyword on the FABITAB macro statement.

The SS-STATS routine prints a second table where the number of root segments and the number of data bytes are expressed as the percentage of all databases.

The SS-STATS routine also prints how many database roots are orphans. An orphan is a root segment which does not belong to any subset. The number of orphans should be zero, if the SSRGEN specifications (as input for the generation of the Sequential Subset Randomizer) have been done correctly.