IT37233: ROLLBACK OF A PAGE ALTER POTENTIALLY CORRUPTING THE PAGE'S SLOT TABLE IF VARCHAR CHANGE INVOLVED

APAR status

• Closed as program error.

Error description

• With in-place alters, a table can contain data pages containing
  old version rows.  Eventually, e.g. upon updating one of those
  old version rows, the containing page and all its rows would be
  altered to the latest schema version.
  
  If the in-place alter history between such page's version and
  the current version includes a varchar length change and such
  page alter happens to occur in a transaction that, for some
  reason, later gets rolled back, the page potentially will be
  left in a corrupted state, with part of its slot table
  overwritten.  The corruption will not be detected until next
  access to any row on this page, so an assertion might occur only
  long after the fact.
  
  The problem is more likely with MAX_FILL_DATA_PAGES on, so if
  pages can be very full with variable length columns.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of Informix Server prior to 12.10.xC16 and 14.10.xC7.  *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * See Error Description                                        *
  ****************************************************************
  * RECOMMENDATION:                                              *
  * Upgrade to Informix Server 12.10.xC16 or 14.10.xC7.          *
  ****************************************************************
  

Problem conclusion

• Fixed in Informix Server 12.10.xC16 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