PH67087: CONTROL OF NEW DISTRIBUTED CONNECTION REQUESTS

Obtain the fix for this APAR.

APAR status

• Closed as new function.

Error description

• Db2 can sometimes receive a high number of concurrent new
  connection requests which tends to cause work requests
  against already established connections to be delayed
  negatively.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Db2 13 for z/OS Users.                   *
  ****************************************************************
  * PROBLEM DESCRIPTION: Improve handling of new connection      *
  *                      requests                                *
  ****************************************************************
  When a request for a new distributed connection is received,
  Db2 will either create a new DBAT to handle the connection
  request or queue the request on its connection request queue
  and wait for a DBAT to become available to handle the request.
  Any connection request, whether a new connection request
  or a new transaction request on an exisitng connection, when
  queued, is placed on the same connection request queue. This
  approach allows almost all of the possible DBATs to be
  used to handle new connection requests while causing a delay
  in handling new transaction work requests during a possible
  large influx of new connection requests.
  

Problem conclusion

Temporary fix

Comments

• Db2 is being changed to limit the number of DBATs that can
  be used concurrently to process new connection requests
  to 32. The new limit is not configurable, and it always
  applies if Db2 is running with the DSN6FAC CMTSTAT
  subsystem parameter set to INACTIVE, which is generally
  the recommended setting. The new limit is not applicable
  if Db2 runs with CMTSTAT set to ACTIVE.
  The -DISPLAY DDF DETAIL command output is also being
  enhanced with the addition of the new message, DSNL095I.
  The output from DSNL095I will display how many DBATs are
  currently processing new connection requests, if any, and
  how many new connection requests are currently queued
  waiting for a DBAT to process the request.
  
  The online product documentation for Db2 13 is updated for
  new function in this APAR. To find the changes and related
  information, search on "PH67087" and "DSNL095I" at:
  https://www.ibm.com/docs/en/db2-for-zos
  

APAR Information

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

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

  UO05083

Modules/Macros

• DSN@QLST DSNDQDST DSNDQLST DSNFCDIR DSNFLDIR DSNLAGNT DSNLAGNX
  DSNLCRNC DSNLCRTD DSNLEDDA DSNLIIN2 DSNLIINI DSNLIRTR DSNLITR2
  DSNLITRM DSNLQACT DSNLQCRP DSNLQDIS DSNLSSRB DSNLSSRW DSNLSSST
  DSNLTACT DSNLTDDF DSNLTGBK DSNLTMIN DSNLTMSC DSNLTSET DSNLTZCH
  DSNLVCIP DSNLVCLM DSNVDTA  DSNWDFDI DSNWDFDS DSNWVZPS
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RD10 PSY UO05083

     UP25/10/02 P F510  

Fix is available

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