PM58114: CONCURRENT 'LOCK TABLE' AND 'INSERT' ON A PBG TABLESPACE MAY CAUSE PAGE REGRESSION.

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• Dump Title: PR3A,ABND=04E-00C90101,U=SAPADM  ,M=(N),C=910.DMC
  -DSNISDLE,M=DSNTFRCV,LOC=DSNIDM  .DSNICUMW:5003
  In data-sharing environment, one member was executing an appl
  with 'LOCK TABLE IN EXCLUSIVE MODE' on a PBG tablespace.
  After the 'LOCK TABLE', another member issued INSERTs in the
  locked table. Those INSERTs created a new part and inserted rows
  in the new part.
  When the appl with the 'LOCK TABLE' accessed the rows in the new
  part, it didn't take any locks on the new part.
  Concurrent access by the 'LOCK TABLE' appl and other appls on
  the new part caused page regression and missing rows.
  The missing rows caused ABEND04E RC00C90101 DSNICUMW:5003.
  

Local fix

• Avoiding to use 'LOCK TABLE' on PBG tablespace.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All DB2 10 for z/OS and DB2 9 for z/OS       *
  *                 customers that issue                         *
  *                 LOCK TABLE IN SHARE MODE or LOCK TABLE       *
  *                 IN EXCLUSIVE MODE on a Partition By          *
  *                 Growth (PBG) table space can potentially     *
  *                 experience data regression when a new        *
  *                 partition is added.                          *
  ****************************************************************
  * PROBLEM DESCRIPTION: ABEND04E RC00C90101 DSNICUMW ERQUAL5003 *
  *                      Data loss due to regressed pages.       *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  For a PBG table space, locks are taken at each partition level
  instead of the entire table or table space when a LOCK TABLE IN
  EXCLUSIVE MODE SQL statement is issued. After the LOCK TABLE
  operation completed, another agent was allowed to proceed with
  an insert operation that forced the creation of a new partition.
  The agent that issued the LOCK TABLE then regressed the data
  rows in the new partition as it should have had exclusive access
  to the entire table.
  

Problem conclusion

• DB2 code has been changed to detect if all partitions are locked
  in exclusive or shared modes and to then avoid growing the PBG
  table space into a new partition by another agent that is doing
  SQL INSERT or UPDATE operations.
  The failing agent will get a RC00C9008E return code to indicate
  a lock timeout condition.
  

Temporary fix

• *********
  * HIPER *
  *********
  

Comments

APAR Information

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

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

  UK77666 UK77667

Modules/Macros

• DSNISUPI
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• RA10 PSY UK77666

     UP12/04/19 P F204

• R910 PSY UK77667

     UP12/04/19 P F204

Fix is available

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