IT41553: DDRBLOCK OR COMPRESSION DICTIONARY TABLE CORRUPTION AFTER ROLLBACK OF A TRANSACTION THAT CREATED AND FILLED A COMPRESSED TABLE

APAR status

• Closed as program error.

Error description

• If a transaction rolls back that created a new auto-compressed
  table/partition AND also inserted enough rows so
  auto-compression would be attempted (and a compression
  dictionary created), this can lead to two separate problems:
  
  1. on systems configured for Enterprise Replication, this will
  lead to a 'ghost' transaction in the grouper
     which will prevent advancement of the replay position and
  eventually DDRBLOCK
     -> such ghost transaction could be seen in 'onstat -g grp T'
  as a transaction containing only a single UNDO operation
  
  If this is the only transaction known to the grouper and the
  send queue is empty, the situation can be solved by a 'cdr
  cleanstart'.
  
  2. on clustered systems, it will leave that compression
  dictionary in a non-dropped state on any secondary server
     and corrupt an index on the respective compression dictionary
  partition at that
     This problem cannot really be detected (and won't do much
  harm) as long as this secondary remains a secondary.
  
  
  One example for such transaction is an ALTER TABLE on a
  compressed table that happens to be executed as a slow alter and
  doesn't run to completion, but gets interrupted at some point.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 14.10.FC10.                *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 14.10.FC10.                       *
  ****************************************************************
  

Problem conclusion

• Fixed in Informix Server 14.10.FC10.
  

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