IT32654: ACTIVITY EVENT MONITORS RETURN INCORRECT CPU TIME FOR SP CALLS WITH NESTED STATEMENTS

Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows
Db2 Version 11.1 Mod 4 Fix Pack 6 for Linux, UNIX, and Windows

APAR status

• Closed as program error.

Error description

• If you have defined activity event monitors to get CPU times for
  stored procedures with nested statements, you may get incorrect
  results.
  
  Example :
  
  CREATE PROCEDURE SP1 (
  IN IN_STMT VARCHAR(10000)
  )
  LANGUAGE SQL
  SPECIFIC EXECSQL
  MODIFIES SQL DATA
  NOT DETERMINISTIC
  COMMIT ON RETURN NO
  NO EXTERNAL ACTION
  BEGIN
  EXECUTE IMMEDIATE in_stmt;--
  END@
  
  
  CREATE EVENT MONITOR "DB2ACTIVITIES"
  FOR ACTIVITIES
  WRITE TO TABLE ACTIVITY (TABLE ACTIVITY_DB2ACTIVITIES"),
  ACTIVITYMETRICS (TABLE "ACTIVITYMETRICS_DB2ACTIVITIES"),
  ACTIVITYSTMT (TABLE ACTIVITYSTMT_DB2ACTIVITIES"),
  ACTIVITYVALS (TABLE "ACTIVITYVALS_DB2ACTIVITIES"),
  CONTROL (TABLE "CONTROL_DB2ACTIVITIES")
  AUTOSTART@
  
  
  call sp ( 'delete from tab1 where 1=1')
  
  db2 "SELECT UOW_ID,ACTIVITY_ID,SYSTEM_CPU_TIME,USER_CPU_TIME
  From ACTIVITY_DB2ACTIVITIES"
  
  UOW_ID ACTIVITY_ID SYSTEM_CPU_TIME USER_CPU_TIME
  ----------- -------------------- --------------------
  --------------------
  1007 2 21 2616
  1007 1 374 5752
  
  $ db2 "SELECT UOW_ID,ACTIVITY_ID, SUBSTR(STMT_TEXT, 1,70) AS
  STMT_TEXT FROM ACTIVITYSTMT_DB2ACTIVITIES"
  
  UOW_ID ACTIVITY_ID STMT_TEXT
  ----------- --------------------
  ----------------------------------------------------------------
  ------
  1007 2 delete from cpu where 1=1
  1007 1 CALL sp1(?)
  
  CPU time for the SP is twice the CPU time of the delete.
  

Local fix

• Use TOTAL_CPU_TIME returned by ACTIVITYMETRICS
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * All Db2 users                                                *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to at least Db2 11.1 Mod 4 Fix Pack 6                *
  ****************************************************************
  

Problem conclusion

• Problem was first fixed Db2 11.1 Mod 4 Fix Pack 6
  

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:

Fix information

• Fixed component name

  DB2 FOR LUW

• Fixed component ID

  DB2FORLUW

Applicable component levels

• RB10 PSY

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