PI77214: INCREASE SYSTEM DEFAULT NUMBERS OF HSSR BUFFERS

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Increase the system default numbers of HSSR buffers.
  BUF=*ALL,96 improves the IPR Unload utility's performance (OSAM
  BLKSIZE=4096). The system default numbers of CAB buffers are too
  small.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of IMS High Performance Unload for *
  *                 z/OS Version 1 Release 2 (FMID=H1IN120)      *
  ****************************************************************
  * PROBLEM DESCRIPTION: This APAR provides the new control      *
  *                      statement CABBASE to specify basic size *
  *                      for the CAB.                            *
  ****************************************************************
  * RECOMMENDATION: Apply the maintenance for this APAR.         *
  ****************************************************************
  This APAR provides the new control statement CABBASE.
  This CABBASE control statement is basic size for CAB buffers
  and simpler than current CAB control statements.
  

Problem conclusion

Temporary fix

Comments

• ========================
  = DOCUMENTATION CHANGE =
  ========================
  The IBM IMS High Performance Unload for z/OS User's Guide
  Version 1 Release 2 Suffix 8 (SC27-0936-08) should be changed
  as follows:
  ----------------------------------------------------------------
  > Unloading IMS databases
  >> Options for HSSR Engine
  |>>> CABBASE Control Statement
  |
  | This optional control statement specifies the number of tracks
  | as the basic size of I/O buffers allocated by CAB.
  | The RANSIZE and NBRDBUF values are determined from this value
  | and CI/block size of database data set.
  | If the RANSIZE control statement or the NBRDBUF control
  | statement is specified in the HSSRCABP data set, it is prior
  | to this statement.
  |
  | 0........1.........2.........3.........4.........5..
  | 1234567890123456789012345678901234567890123456789012
  | CABBASE trk dbam typ
  |
  | Position  Description
  | 1         Code the CABBASE keyword.
  | 9         Code the numeric value trk to be left-aligned
  |           decimal number in the range of 1 - 255.
  |           For VSAM sequential buffer, the range is 1 - 15.
  | 13        ALL   Indicate that this statement applies to all
  |                 all ESDS or OSAM data sets.
  |                 This string must be left-aligned.
  |                 ALL is the default.
  |           VSAM  Indicate that this statement applies to all
  |                 ESDS data sets.
  |           OSAM  Indicate that this statement applies to all
  |                 OSAM data sets.
  | 18        ALL   Indicate that this statement applies to
  |                 sequential and direct buffer.
  |                 ALL is the default.
  |           SEQ   Indicate that this statement applies to
  |                 sequential buffer.
  |           DIR   Indicate that this statement applies to
  |                 direct buffer.
  |
  | The default value is determined depending on the access
  | method as following;
  |   CABBASE 1   OSAM SEQ
  |   CABBASE 2   OSAM DIR
  |   CABBASE 8   VSAM SEQ
  |   CABBASE 15  VSAM DIR
  |
  | If VSAM CI size is smaller than 2 KB, the following values
  | are used internally.
  |   CABBASE 4   VSAM SEQ
  |   CABBASE 8   VSAM DIR
  |
  | Tips:
  | - The following statement is recommended in order to improve
  |   performance of CAB sequential I/O for OSAM data sets.
  |     CABBASE 8  OSAM SEQ
  |   The base size for sequential buffers for an OSAM data set
  |   is changed from 1 track to 8 tracks.
  | - The default of this control statement can be changed by
  |   replacing the default option table (FABHOPT). For details,
  |   see Chapter 19, "Site default options".
  ---------------------------------------------------------------
  > Tuning and customizing HSSR application jobs
  >> Site default options
  >>> How the runtime parameters are determined
  
  Table 1. Options for which default values can be specified
  | Function: HSSR Engine options
  | Keyword: CABBASE_OS
  | Description: CABBASE option for sequential buffer of OSAM
  | Related data set: HSSROPT
  | Function: HSSR Engine options
  | Keyword: CABBASE_OD
  | Description: CABBASE option for direct buffer of OSAM
  | Related data set: HSSROPT
  | Function: HSSR Engine options
  | Keyword: CABBASE_VS
  | Description: CABBASE option for sequential buffer of ESDS
  | Related data set: HSSROPT
  | Function: HSSR Engine options
  | Keyword: CABBASE_VD
  | Description: CABBASE option for direct buffer of ESDS
  | Related data set: HSSROPT
  ---------------------------------------------------------------
  >>> FABHTOPT macro statements
   (label)     FABHTOPT     COMPAT= HPU|DBT|5787LAC
  |                               :
  |                                ,CABBASE_OS=nnn
  |                                ,CABBASE_OD=nnn
  |                                ,CABBASE_VS=nnn
  |                                ,CABBASE_VD=nnn
  
  Table 1. Basic settings of FABHTOPT options
   +-------------+-------------+-------------+----------------+
   | Keyword     |COMPAT=HPU   | COMPAT=DBT  | COMPAT=5787LAC |
   +-------------+-------------+-------------+----------------+
   :             :             :             :                :
   +-------------+-------------+-------------+----------------+
  || CABBASE_OS= | 1           | 1           | 1              |
  |+-------------+-------------+-------------+----------------+
  || CABBASE_OD= | 2           | 2           | 2              |
  |+-------------+-------------+-------------+----------------+
  || CABBASE_VS= | defnum      | defnum      | defnum         |
  ||             | (see Note2) | (see Note2) | (see Note2)    |
  |+-------------+-------------+-------------+----------------+
  || CABBASE_VD= | defnum      | defnum      | defnum         |
  ||             | (see Note2) | (see Note2) | (see Note2)    |
  |+-------------+-------------+-------------+----------------+
   :             :             :             :                :
   +----------------------------------------------------------+
   | Note: The number is determined from the block size of    |
   |       the output data set by each unload utility.        |
  || Note2: The number is determined from the CI size of the  |
  ||        database data set.                                |
   +----------------------------------------------------------+
  
    You can use the following keywords to override the values
    set by the basic settings:
    :
  | CABBASE_OS=
  |   This optional keyword specifies the default for
  |   the 'CABBASE nnn OSAM SEQ' option in HSSROPT.
  | CABBASE_OD=
  |   This optional keyword specifies the default for
  |   the 'CABBASE nnn OSAM DIR' option in HSSROPT.
  | CABBASE_VS=
  |   This optional keyword specifies the default for
  |   the 'CABBASE nnn VSAM SEQ' option in HSSROPT.
  | CABBASE_VD=
  |   This optional keyword specifies the default for
  |   the 'CABBASE nnn VSAM DIR' option in HSSROPT.
  ---------------------------------------------------------------
  > Troubleshooting
  >> Messages and codes
  >>> Messages
  >>>> FABH messages
  ---------------------------------------------------------------
  | FABH0697E INCORRECT CABBASE CONTROL STATEMENT IS SPECIFIED
  |
  | Explanation: An incorrect operand on the CABBASE control
  | statement is specified in the HSSROPT data set.
  | System action: The incorrect statement is ignored.
  | User response: Correct the CABBASE statement.
  ---------------------------------------------------------------
  | FABH2016E INCORRECT CABBASE_xx= PARAMETER IS SPECIFIED
  |
  | Explanation: The value specified for the CABBASE_xx= keyword
  | parameter is incorrect. It must be in the range of 1 - 255.
  | System action: The assembly of the option table ends with
  | return code 8. The option table is not replaced.
  | User response: Correct the error.
  ---------------------------------------------------------------
    FABH0056W NUMBER OF BUFFERS IN A SEQ_BUF xxx CHANGE TO yyy
  
    Explanation: The number (xxx) of CIs to be read by one
    sequential read for the data set identified by ddname is too
    large. The number xxx is the one that was specified by the
  | RANSIZE control statement or the CABBASE control statement.
    The ESDS cannot chain CCWs for that number of CIs in a single
    start I/O. The maximum number of CIs (yyy) that can be read
    depends on the CI size and is displayed in the message.
    System action: The processing continues with the maximum
    number (yyy) of CIs.
    User response: Specify the value yyy indicated in the message
    for RANSIZE.
  ---------------------------------------------------------------
  ================ End of Documentation Change ==================
  

APAR Information

• APAR is sysrouted FROM one or more of the following:

• APAR is sysrouted TO one or more of the following:

  UI46101

Modules/Macros

•    FABHA00  FABHDOPT FABHOPT  FABHTCBU FABHTGBL
  FABHTOPT FABH000  FABH001  FABH015  FABH015A FABH511  FABH512
  HPSUSTMT HPSU015  HPSU015A
  

Fix information

• Fixed component name

  IMS HIGHPERF UN

• Fixed component ID

  5655E0600

Applicable component levels

• R120 PSY UI46101

     UP17/04/05 P F704

Fix is available

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