PK68746: DDF JCC APPLICATION WITH DEGRADED PERFORMANCE WHEN MULTIPLE CNTQRY OCCUR, CURSOR IS CLOSED BUT NO COMMIT OCCURS

Obtain the fix for this APAR.

APAR status

• Closed as program error.

Error description

• DB2DDF DDFL09 DB2DRDA Defects 114727 d114727
  JCC application experiences slower than expected response time.
  Multiple cntqry occur, the cursor is closed but no commits
  are done. The open cursor flag is set to off, but the fast close
  flag is not st to on.
  Due to the fast close flag being off, the
  endqryrm is sent but no commit occurs.
  

Local fix

• no local workaround
  

Problem summary

• ****************************************************************
  * USERS AFFECTED: All Distributed Data Facility (DDF) users.   *
  *                 Specifically those using the IBM Data Server *
  *                 Driver for JDBC and SQLJ Type 4 Connectivity *
  *                 client connecting to DB2 for z/OS server.    *
  ****************************************************************
  * PROBLEM DESCRIPTION: Degraded performance is observed for    *
  *                      applications using the IBM Data Server  *
  *                      Driver for JDBC and SQLJ Type 4         *
  *                      Connectivity client with autocommit     *
  *                      enabled when connected to DB2 for z/OS  *
  *                      server.                                 *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  A client application issues an open cursor request to a DB2 for
  z/OS server.  The client application has autocommit enabled.
  The DB2 for z/OS server opens the cursor, fetches to end of
  data, fast closes the cursor, and sends all the rows back to the
  client.  After processing the output rows, the client honors
  autocommit by sending a commit request to the DB2 for z/OS
  server.  The DB2 for z/OS server drives commit successfully and
  returns a commit reply to the client.  The commit request and
  reply flows used to honor autocommit results in degraded
  performance as compared to when autocommit is not enabled.
  

Problem conclusion

• New function is added to the DB2 for z/OS server that allows
  a client system to request an implicit commit at cursor open
  time.  When a client requests implicit commit, the server will
  drive commit whenever a cursor is fast closed.  This eliminates
  the additional commit related network exchange that is required
  in order to honor autocommit, and hence results in improved
  performance.
  To exploit this performance enhancement, changes are required at
  both the server and client.  This APAR implements the DB2 for
  z/OS server side changes.  IBM Data Server Driver for JDBC and
  SQLJ Type 4 Connectivity client side changes are provided in a
  companion V9.1 FP4 special build (3.6.98), and will also be
  included in the V9.1 FP7 release.
  

Temporary fix

Comments

• ž**** PE09/09/10 FIX IN ERROR. SEE APAR PK94943  FOR DESCRIPTION
  

APAR Information

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

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

  UK42748 UK42749

Modules/Macros

• DSNDDDXB DSNDDRDB DSNDEXTN DSNDLRQS DSNDPRDS
  DSNLDICT DSNLTCM1 DSNLTDSR DSNLTEXC DSNLXCQH DSNLXCQ6 DSNLXCQ7
  DSNLXGCS DSNLXHOC DSNLXHOP DSNLXMRS DSNLXOQS DSNLXPCA DSNLXRES
  DSNLXRSS DSNLXXSS DSNLZNUM DSNLZSQL DSNLZSRM DSNLZS00
  

Fix information

• Fixed component name

  DB2 OS/390 & Z/

• Fixed component ID

  5740XYR00

Applicable component levels

• R810 PSY UK42748

     UP09/01/07 P F901

• R910 PSY UK42749

     UP09/01/07 P F901

Fix is available

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