IT34374: INCORRECT ERRNO REPORTED AND AMBIGUOUS OS SYSTEM CALL FAILURE DURING ASSERTIONS FOR I/O FAILURES

APAR status

• Closed as program error.

Error description

• When a problem is encountered trying to process some I/O
  requests the server can product the following type of assertion
  messages in MSGPATH file:
  
  08:19:08  Assert Warning: I/O read chunk 272, pagenum 5346364,
  pagecnt 4 --> errno = 2
  08:19:08  IBM Informix Dynamic Server Version 11.70.FC9X1
  08:19:08   Who: Session(660, user@host, -1, 4a8be56f8)
                  Thread(184827, scan_2.0, 49dd9f728, 1)
                  File: rsbuff.c Line: 5634
  08:19:08   Action: Please notify IBM Informix Technical Support.
  08:19:08  stack trace for pid 1066 written to /path/af.d5e30e3c
  08:19:08   See Also: /path/af.d5e30e3c
  08:19:08  I/O read chunk 272, pagenum 5346364, pagecnt 4 -->
  errno = 2
  
  This message indicates errno is 2, however, when looking the
  contents of the af file we see the following:
  
  08:22:35  mt_aio_wait(4a2ab5c68)
  08:22:35  chunkio(56, 0x2a47c4000, 0x3f1ec0, 4, 0x49df25228, 33,
  1) errno 9
  AIOREQ *a
  
  
  This is actually correctly reporting errno 9 from the actual
  AIOREQ.  This was addressed as part of the fix of idsdb00495796.
  However, that defect seemed to not address the errno reported in
  the MSGPATH output.
  
  Additionally, this message implies a read failure, when in the
  process of debugging, the actual failure occurred when
  attempting to open the chunk.  So there is no indication of a
  failing open, and due to the failing open, the server is
  manually setting errno to 9/EBADF so there is no trace of the
  error being reported by the open.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 12.10.xC15 and 14.10.xC7.  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 12.10.xC15 or 14.10.xC7 (when     *
  * available).                                                  *
  ****************************************************************
  

Problem conclusion

• Fixed in Informix Server 12.10.xC15 and 14.10.xC7.
  

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