IT31851: A CHUNK CAN BE EXTENDED PAST THE INTERNAL LIMIT OF 2,147,483,647PAGES

APAR status

• Closed as program error.

Error description

• When chunk extension is enabled, it is possible to extend the
  size of a chunk beyond the internal limit of 2,147,483,647
  (0x7fffffff) pages.
  
  When this happens, the first symptom is a negative chunk size in
  the
  onstat -d output.  However, this will also lead to I/O errors as
  the server attempts
  to use the chunk pages that are now all beyond the negative
  chunk size.  Examples:
  
  Chunk <chunk_num> in space '<dbspace_name>' has been extended by
  14497846 kb.
  I/O bad request chunk <chunk_num>, pagenum 1807035447, pagecnt 1
  I/O bad request chunk <chunk_num>, pagenum 111209559, pagecnt 1
  I/O bad request chunk <chunk_num>, pagenum 2037804858, pagecnt 1
  I/O bad request chunk <chunk_num>, pagenum 111263159, pagecnt 1
  Assert Warning: I/O bad request chunk <chunk_num>, pagenum
  891944057, pagecnt 1
  

Local fix

• Disable chunk extension if the chunk is anywhere near
  2,147,483,647 pages.
  
  EXECUTE FUNCTION task("modify chunk extendable off", "chunk
  number");
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 12.10.xC14 and 14.10.xC4.  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Update to Informix Server 12.10.xC14 or 14.10.xC4 (when      *
  * available).                                                  *
  ****************************************************************
  

Problem conclusion

• Update to Informix Server 11.70.xC9W2, 12.10.xC14 and 14.10.xC4.
  
  
  Change summary:
  The server now calculates the maximum size of a chunk based on
  the dbspace's page size and ensures that no chunk is extended
  beyond that size.   If the chunk is at the maximum size, the
  server will turn off the extendable flag and will not allow the
  chunk to be made extendable again.  Messages are written to the
  online message log explaining the reason for the new behavior.
  

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