IT00258: ONLINE-CDC WILL GENERATE PARTIAL RECORDS IF YOUR TABLE HAS A LAR GE ROW SIZE. ONLINE-CDC LIMITS IFX_LO_READ() TO ONLY FETCH 32000

APAR status

• Closed as documentation error.

Error description

• If your row size is over 32000 bytes. ONLINE-CDC will split the
  CDC record being return, limiting ifx_lo_read() to fetch only
  32000 bytes and the application developer must recognize that
  this is a partial record and fetch the rest of the record with
  another call to ifx_lo_read().
  
  This behavior is not documented and appears to be a design issue
  with the Informix implementation of the CDC API.
  The only way a developer would know to do this is to reference
  the example provided in the cdcapi.ec
  

Local fix

• Review cdcapi.ec and when a partial record is retrieved you must
  retrieve the rest of the record with another call to
  ifx_lo_read()
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of the Informix log capture API (CDC)                  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Refer to the cdcapi.ec sample program in the                 *
  * $INFORMIXDIR/demo/cdc directory.  Informix versions          *
  * 12.10.xC4 and later also remove an internal constraint that  *
  * in this case limited the amount of data returned in a single *
  * read call to approximately 32 KB.                            *
  ****************************************************************
  

Problem conclusion

• Your application cannot depend on a specific number of records
  being returned by smart large object read calls. The number of
  CDC records that are returned in a read call is not predictable
  and might not be an integral number. If a read call returns only
  part of a CDC record, the next read call
  returns more data for that record. Your application must merge
  the parts of the record that are returned in multiple read
  calls. The Change Data Capture sample program provides examples
  of merging parts of records.
  

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

Applicable component levels