OA08949: NEW FUNCTION

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• New Function
  

Local fix

• n/a
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All users of z/OS 1.5                        *
  *                 (HBB7708) and above.                         *
  ****************************************************************
  * PROBLEM DESCRIPTION: New function to add short time enqueue  *
  *                      promotion for DB2.                      *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  Currently, SYSEVENT ENQHOLD is available for resource managers
  to identify to SRM the holder of a resource for which there is
  contention. SRM may boost the service to the holder of the
  resource to help resolve the contention more quickly.  The
  issuer of SYSEVENT ENQHOLD is required to issue a SYSEVENT
  ENQRLSE when the holder has released the resource. It has been
  requested that SRM provide a function which allows the DB2
  resource manager to issue a SYSEVENT ENQHOLD to help relieve
  short time enqueue contention without having to issue the
  SYSEVENT ENQRLSE.
  

Problem conclusion

Temporary fix

Comments

• The SRM standard enqueue management will be expanded with the
  new short time enqueue promotion function. The Short time
  enqueue promotion function allows a resource manager to use the
  SYSEVENT ENQHOLD to signal short time resource contention to
  SRM. This function causes SRM to boost the resource holder for a
  small fixed number of service units. Once the small fixed number
  of service units has been consumed, SRM will end the enqueue
  promotion. The resource holder is always allowed to consume the
  entire short promotion time. Therefore, with short time enqueue
  promotion, it is no longer necessary for the resource manager to
  issue the SYSEVENT ENQRLSE when the contention ends. This avoids
  unnecessary overhead for the resource manager in bookkeeping an
  enqueue hold token and issuing SYSEVENT ENQRLSE. No enqueue hold
  token is returned when issuing a short time SYSEVENT ENQHOLD
  request.
  
  Short time enqueue promotion is independent of the standard
  enqueue promotion, in the sense that they do not interfere with
  one other. Work currently subject to promotion via either the
  short time or standard mechanism is promoted in the same way,
  using the existing base implementation. The short promotion time
  is fixed and has a value of approximately 10 service units. The
  number of service units used by SRM to boost the resource holder
  for a short time enqueue promotion is a fixed value and can not
  be modified. It has no relation to the ERV parameter in the
  IEAOPTxx member.
  
  The standard enqueue promotion and the short time enqueue
  promotion are now available for SYSEVENT ENQHOLD type=3 and
  SYSEVENT ENQRLSE type=3.  SYSEVENT ENQHOLD and SYSEVENT ENQRLSE
  type=0, 1, and, 2 are not affected by these changes and remain
  unchanged.  The SYSEVENT ENQHOLD and SYSEVENT ENQRLSE type=3 has
  a changed parameter list which is described with the mapping
  macro IRAEVPL.  The ASID and ASIDL SYSEVENT parameters were
  moved to this parameter list.  SYSEVENT ENQHOLD type=3 and
  SYSEVENT ENQRLSE type=3 support the STOKEN (space token) in
  addition to the ASID (Address space ID).  SYSEVENT ENQHOLD
  type=3 and SYSEVENT ENQRLSE type=3 cause SRM to write an
  additional SSRV system trace entry with ID SYSEVENT (ssid=005F),
  which expands the scope of identifying the resource holder:
  Word1 - contains the Oucb address of the resource holder or
          0 if not available.
  Word2 - contains the Encb address of the resource holder or
          0 if not available.
  Word3 - Bytes0 and 1 contains the function code,
          Byte2 contains the Type, and
          Byte3 contains the SYSEVENT code.
  Word4 - contains the TCB address of the resource holder or
          0 if not available.
  Word5 - contains the address of the EHE (enqueue hold element)
  
  
  With SYSEVENT ENQHOLD type=3 and SYSEVENT ENQRLSE type=3, the
  availability is now indicated in the return area of
  SYSEVENT(REQSRMST), which is mapped by IRASRMST.
  

APAR Information

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

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

  UA17135 UA17136

Modules/Macros

• IEAVENST IEAVNP10 IEEMB812 IRACCT   IRACQEHE
  IRAENCB  IRAEVCFG IRAEVENQ IRAEVENT IRAEVMAP IRAEVPL  IRAEVREQ
  IRAEVSSI IRAOLST  IRAOUCBX IRARMCNS IRARMEHE IRARMELM IRARMERR
  IRARMER2 IRARMER4 IRARMER5 IRARMEVT IRARMFME IRARMFMO IRARMFMT
  IRARMOPT IRARMPT  IRARMSOP IRASETNP IRASRMST IRASSISA SYSEVENT
  

Publications Referenced

SA22761205

GA22758206

GA22758207

GA22758805

GA22758806

Fix information

• Fixed component name

  5752 SYS RSRCE

• Fixed component ID

  5752SC1CX

Applicable component levels

• R708 PSY UA17135

     UP05/03/23 P F503

• R709 PSY UA17136

     UP05/03/23 P F503

Fix is available

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Product categories:

Software

Operating System

z/OS family

APARs - z/OS environment

Operating system(s):

MVS, z/OS

Software version:

709

Reference #:

OA08949

IBM Group:

IBM Server Group

Modified date:

2005-04-02