IT27526: ONDBSPACEDOWN ALLOWING A CHECKPOINT WITH I/O ERRORS TO COMPLETE

APAR status

• Closed as program error.

Error description

• With ONDBSPACEDOWN 2 (wait) you could see the following:
  
  01:54:22  Assert Warning: I/O write chunk 28, pagenum 20,
  pagecnt 4 --> errno = 2
  01:54:22  IBM Informix Dynamic Server Version 12.10.FC5W1XZ
  01:54:22   Who: Thread(13, flush_sub(1), 6207b1a8, 11)
                  File: rsbuff.c Line: 5725
  01:54:22   Action: Please notify IBM Informix Techical Support.
  01:54:22  stack trace for pid 113092 written to
  /opt/informix/tmp/af.3f5d91d
  01:54:22   See Also: /opt/informix/tmp/af.3f5d91d
  01:54:22  I/O write chunk 28, pagenum 20, pagecnt 4 --> errno =
  2
  01:54:33  Checkpoint Completed:  duration was 70 seconds.
  01:54:33  Sat Nov 18 - loguniq 84375, logpos 0x3926b018,
  timestamp: 0xd2a3ebff Interval: 324187
  
  01:54:33  Maximum server connections 806
  01:54:33  Checkpoint Statistics - Avg. Txn Block Time 0.122, #
  Txns blocked 27, Plog used 130899, Llog used 266693
  
  01:54:33  WARNING: Checkpoint blocked by down space, waiting for
  override or shutdown
  02:00:07  Logical Log 84376 Complete, timestamp: 0xd2a401a4.
  02:00:07  Logical Log 84376 - Backup Started
  
  
  That is, the ongoing checkpoint incurring errors flushing dirty
  buffers to disk is allowed to complete and only the next
  checkpoint would be blocked.
  
  Consequently, after 'onmode -ky', chunks would not be marked
  down and fast recovery would start at that inconsistent, but
  complete checkpoint:
  
  ...
  02:02:59  Logical Recovery Started.
  02:02:59  56 recovery worker threads will be started.
  02:03:04  Fast Recovery Switching to Log 84376
  02:03:05  Fast Recovery Switching to Log 84377
  02:03:06  Logical Recovery has reached the transaction cleanup
  phase.
  02:03:12  Checkpoint Completed:  duration was 6 seconds.
  02:03:12  Sat Nov 18 - loguniq 84376, logpos 0x35e5018,
  timestamp: 0xd2aa771e Interval: 324188
  
  02:03:12  Maximum server connections 0
  02:03:12  Checkpoint Statistics - Avg. Txn Block Time 0.000, #
  Txns blocked 0, Plog used 16455, Llog used 0
  
  02:03:13  Checkpoint Completed:  duration was 0 seconds.
  02:03:13  Sat Nov 18 - loguniq 84377, logpos 0x1018, timestamp:
  0xd2aa774d Interval: 324189
  
  02:03:13  Maximum server connections 0
  02:03:13  Checkpoint Statistics - Avg. Txn Block Time 0.000, #
  Txns blocked 0, Plog used 1900, Llog used 2
  
  02:03:14  Logical Recovery Complete.
            21224 Committed, 21 Rolled Back, 0 Open, 0 Bad Locks
  
  02:03:15  Onconfig parameter RAS_PLOG_SPEED modified from 148485
  to 89735.
  02:03:15  Onconfig parameter RAS_LLOG_SPEED modified from 690 to
  1565.
  02:03:15  Dataskip is now OFF for all dbspaces
  02:03:15  listener-thread: err = -27002: oserr = 0: errstr = :
  No connections are allowed in quiescent mode.
  
  02:03:16  Checkpoint Completed:  duration was 0 seconds.
  02:03:16  Sat Nov 18 - loguniq 84377, logpos 0x290c0, timestamp:
  0xd2aa7fae Interval: 324190
  
  02:03:16  Maximum server connections 0
  02:03:16  Checkpoint Statistics - Avg. Txn Block Time 0.000, #
  Txns blocked 0, Plog used 1562, Llog used 41
  
  02:03:16  On-Line Mode
  
  ... which can be told from interval number of first checkpoint
  after fast recovery.
  
  What seemingly got through fast recovery fine, indeed is missing
  at least one page flushed to disk and has to be considered
  inconsistent, with oncheck likely to find corruption.
  In a clustered environment this also can be assumed to be the
  cause of (differing) corruptions on HDR secondary or RSS.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of IDS 12.10.xC10 and earlier versions.                *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * ONDBSPACEDOWN allowing a checkpoint with I/O errors to       *
  * complete.                                                    *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  

Problem conclusion

• Fixed in IDS 12.10.xC11.
  

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