OA49604: MSGIEC161I RC020 RSN053 WHEN USING VSAM SMB

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• When using VSAM SMB and the ACCBIAS value of DO is specified or
  selected by VSAM and the index component is large you may
  receive message IEC161I (020-053). This indicates that VSAM was
  not able to build one or more control blocks and the open of the
  data set will fail.
  

Local fix

• Use of the SMBVSP parameter to limit the amount of storage may
  help in some cases, but not all if the index component is large.
  Specifying ACCBIAS=DW may allow the data set to be opened and
  processed.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Users of VSAM System Managed                             *
  * Buffering (SMB).                                             *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * Jobs that use SMB to process many                            *
  * data sets with large indexes may                             *
  * exhaust virtual storage when running                         *
  * under Direct Optimized. When this                            *
  * happens a user will get a                                    *
  * IEC161I 020-053 message.                                     *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Apply PTFs.                                                  *
  ****************************************************************
  System Managed Buffering (SMB) will try to allocate enough
  buffers to fit the entire index when running under Direct
  Optimized. Users that process many data sets with large indexes
  may exhaust virtual memory. Currently, there is no way to limit
  the virtual storage acquired for the index buffers when using
  Direct Optimized Buffering.
  
  A new parameter, SMBVSPI, is added to Direct Optimized
  processing for SMB. SMBVSPI can only be specified on the AMP
  JCL statement. This new parameter can be used to control
  the virtual storage acquired for the index buffers. It can be
  used along with the existing parameter SMBVSP or by itself.
  SMBVSPI will take precedence in controling the virtual
  storage for the index buffers when it is used along with
  SMBVSP. That is, SMBVSPI will control the virtual storage
  for the index buffers and SMBVSP will control the virtual
  storage for the the data buffers only.
  
  The changes to the SMB documentation is summarized below.
  
  DFSMS Using Data Sets section "Tuning for System-Managed
  Buffering."
  SC23-6855-00
  
  To optimize your extended format data sets, use the ACCBIAS
  subparameter of the AMP parameter along with related
  subparameters SMBVSP, SMBVSPI, SMBDFR and SMBHWT. You can also
  use these subparameters with Record Access Bias=SYSTEM in the
  data class. These subparameters are only for Direct Optimized
  
  
  DFSMS Using Data Sets section "Processing Techniques"
  SC23-6855-00
  
  The following four options, SMBVSP, SMBVSPI, SMBDFR and
  SMBHWT, are only for processing with the Direct Optimized
  technique.
  
  SMBVSP. This option specifies the amount of virtual storage
  to obtain for buffers when a data set is opened. You can
  specify the virtual buffer size in kilobytes, from 1K to
  2048000K, or in megabytes, from 1M to 2048M. The SMBVSP
  2048000K, or in megabytes, from 1M to 2048M. The SMBVSP
  parameter can be used to control the size of the pool that is
  built for the data component. You can also use SMBVSP to
  increase the storage amount used for both data buffer space
  and index buffer space when SMBVSPI is not used. Without
  SMBVSPI, VSAM chooses a maximum number of index buffers,
  either based on 20% of the SMBVSP value that you specify
  or enough for all the index records currently in the
  data set. You can use SMBVSP to improve performance
  when too few index buffers were allocated for a data set
  that grows from small to large, without being closed
  and reopened over time.
  
  SMBVSPI. This option specifies the amount of virtual
  storage to obtain for index buffers when an index is
  opened. You can specify the virtual buffer size in kilobytes,
  from 1K to 2048000K, or in megabytes, from 1M to 2048M.
  
  You can use SMBVSPI to control the pool size that is
  built for the index so that virtual storage is not
  exhausted. You can also use SMBVSPI to increase the index
  pool size so that there are enough buffers for an index
  that grows significantly after it is initially opened.
  
  SMBVSPI can be used by itself or with the SMBVSP
  parameter. SMBVSPI takes precedence over SMBVSP for
  controlling the virtual storage for the index buffers.
  SMBVSPI will control the pool size for the
  index and SMBVSP will control the pool size for the data
  component when both parameters are used together. SMB
  will have the best performance when enough virtual
  space is given to contain all of the index.
  
  
  z/OS DFSMS Using Data Sets section "Processing Guidelines and
  Restrictions"
  SC23-6855-00
  
  You can use the SMBVSP parameter to control the size of the
  pool that is built for the data component or to expand the
  size of the pool for the index records. However, the size
  of the pool for the index records will not be affected by
  SMBVSP when SMBVSPI is used. SMBVSPI can be used to
  restrict the size of the pool that is built for the index
  component. This can be done when the index is so large
  that it exhausts virtual storage. The SMBHWT parameter
  can be used to provide buffering in Hiperspace in combination
  with virtual buffers for the data component.
  
  z/OS MVS JCL Reference Chapter 12, Table 16
  2nd Row "Keyword Parameters"
  SA23-1385-30
  
  SMBDFR=  {Y | N}
  
  SMBHWT=  nn
  
  SMBVSP=  {nnK | nnM}
  SMBVSPI= {nnK | nnM}
  

Problem conclusion

Temporary fix

Comments

APAR Information

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

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

  OA55136 OA55230 UA95730 UA95731 UA95732

Modules/Macros

• IDA0192A IDA0192C IDA0192B IDA0192E IDA0192G IDA0192F IDA0192H
  IDA0200B IDA0192J IDA0557B IEFNB902 IDA0A05B IDA0192Z IDA0200T
  IDA0557E
  

Fix information

• Fixed component name

  DFSMS VSAM

• Fixed component ID

  5695DF106

Applicable component levels

• R210 PSY UA95731

     UP18/05/17 P F805  

• R220 PSY UA95732

     UP18/05/17 P F805  

• R230 PSY UA95730

     UP18/05/17 P F805  

Fix is available

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