IT40284: SECONDARY SERVER BACKLOG DUE TO MISSING READ-AHEAD RECOVERING CLR RECORDS

APAR status

• Closed as program error.

Error description

• When log recovery rolls forward a rollback found in the logical
  logs, it has to access old log records pointed to by CLR records
  as well as data/index pages referenced by those old log records
  Old log records' log. log pages have to be read from disk into
  bufferpool, yet without any read-ahead, so since this old log
  record lookup is performed by the log scanner (master replay
  thread), it can become a significant bottleneck for log
  recovery.
  In case the rollback is for a transaction whose rollforward
  phase has already been seen by this log recovery, the data and
  index pages had a fairly good chance of still residing in
  bufferpools; if, on the other hand, the rollback is for a
  transaction that occurred well before the fast/log recovery
  starting point, it would also suffer from missing read-ahead for
  those pages.
  

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