IT32024: QUERY TAKES LONGER TIME AND OPTIMIZER CHOOSES SEQUENTIAL SCAN INSTEAD OF INDEX PATH AFTER RUNNING UPDATE STATISTICS MEDIUM/HIGH.

APAR status

• Closed as program error.

Error description

• After upgrading from 12.10.FC10 to 12.10.FC13 query is doing
  sequential scan and taking longer ( 50 sec to 1 min) after
  running update statistics high/medium.
  
  
  Using index directive query runs in 15-18 secs.
  

Local fix

• A possible workaround may be to set the onconfig parameter
  OPT_SEEK_FACTOR = 0 or 1.
  
  OPT_SEEK_FACTOR is set to favor hash joins on 12.10, and the
  default value is 6 which could be too high in some cases.
  
  onmode -wf OPT_SEEK_FACTOR=0
  or
  onmode -wf OPT_SEEK_FACTOR=1
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 12.10.xC15.                *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 12.10.xC15 (when available).      *
  ****************************************************************
  

Problem conclusion

• Fixed in Informix Server 12.10.xC15.
  

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