IT41728: POSSIBLE WRONG RESULTS USING A COMPRESSED INDEX DEPENDING UPON ISOLATION LEVEL

APAR status

• Closed as program error.

Error description

• Using a compressed index in this query:
  
  select count (*) from tab1 where col1=number
  
  can lead to wrong results, depending on the isolation level
  
  
  SET ISOLATION TO COMMITTED READ; SELECT COUNT (*) FROM tab1
  WHERE col1 = 12345" | dbaccess test
  
        (count(*))
             10979
  
  SET ISOLATION TO DIRTY READ; SELECT COUNT (*) FROM tab1 WHERE
  col1 = 12345 | dbaccess test
  
        (count(*))
            199061
  
  In this example DIRTY READ produced the wrong result
  
  Uncompressing the index leads to correct results for both
  isolation levels.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 14.10.xC9.                 *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 14.10.xC9.                        *
  ****************************************************************
  

Problem conclusion

• Fixed in Informix Server 14.10.xC9.
  

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

  INFORMIX SERVER

• Fixed component ID

  5725A3900

Applicable component levels