JR62455: IDR SCRAPEDTABLECONTEXTSTORAGE ASSUMES AN INTERVAL EXISTS FOR ALL JOURNALS WHICH CAN RESULT IN AN ARRAYINDEXOUTOFBOUNDSEXCEPTION

APAR status

• Closed as program error.

Error description

• When storing a new table definition in the table history
  metadata, CDC can get an ArrayIndexOutOfBoundsException from
  ScrapedTableContextStorage.tableIntervalExists() line 625. This
  is because CDC is assuming a table definition "interval" exists
  for all journals, but it is possible a table definition may not
  have intervals defined for all journals (nodes). This can occur
  if the table was partitioned on only a subset of the DPF nodes
  and the table definition was created when a DDL was read from
  the log. In this case, CDC creates an interval for each node
  (journal) when it sees a "Data Manager" (DM) log record for the
  DDL in the log for that node. CDC uses the log position of this
  log record when creating the interval boundaries. An "interval"
  is how CDC knows the period in the log for which a table
  definition is valid. DB2 is only required to log a DM log
  record on a node where a partition of that table resides. If
  the table is not partitioned on all nodes, CDC may not see a DM
  log record on the nodes which do not have a partition for that
  table. In that case, there will be no interval for some
  journals. CDC was using a for loop over all journals and
  expecting the number of intervals to be equal to the number of
  journals. If there are fewer intervals, without the fix, CDC
  can try to access an interval that does not exist and get an
  ArrayIndexOutOfBoundsException from
  ScrapedTableContextStorage.tableIntervalExists() line 625. The
  fix is to convert the for loop over all journals to a while
  loop over the intervals that exist, then get the journal Id
  from interval instead of using the for-loop index.
  

Local fix

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * This issue may affect you if you are using CDC for LUW       *
  * version older than 11.4.0.2-5563.                            *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * When storing a new table definition in the table history     *
  * metadata, CDC can get an ArrayIndexOutOfBoundsException from *
  * ScrapedTableContextStorage.tableIntervalExists() line 625.   *
  * This is because CDC is assuming a table definition           *
  * "interval" exists for all journals, but it is possible a     *
  * table definition may not have intervals defined for all      *
  * journals (nodes).                                            *
  * This can occur if the table was partitioned on only a subset *
  * of the DPF nodes and the table definition was created when a *
  * DDL was read from the log.                                   *
  * In this case, CDC creates an interval for each node          *
  * (journal) when it sees a "Data Manager" (DM) log record for  *
  * the DDL in the log for that node.                            *
  * CDC uses the log position of this log record when creating   *
  * the interval boundaries. An "interval" is how CDC knows the  *
  * period in the log for which a table definition is valid. DB2 *
  * is only required to log a DM log                             *
  * record on a node where a partition of that table resides. If *
  * the table is not partitioned on all nodes, CDC may not see a *
  * DM log record on the nodes which do not have a partition for *
  * that table. In that case, there will be no interval for some *
  * journals. CDC was using a for loop over all journals and     *
  * expecting the number of intervals to be equal to the number  *
  * of journals. If there are fewer intervals, without the fix,  *
  * CDC can try to access an interval that does not exist and    *
  * get an ArrayIndexOutOfBoundsException from                   *
  * ScrapedTableContextStorage.tableIntervalExists() line 625.   *
  * The fix is to convert the for loop over all journals to a    *
  * while                                                        *
  * loop over the intervals that exist, then get the journal Id  *
  * from interval instead of using the for-loop index.           *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  

Problem conclusion

• Upgrading to IDR 11.4.0.2-5563 or newer for LUW resolves the
  issue.
  

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

  IS CDC DB2 LUW

• Fixed component ID

  5725E30DL

Applicable component levels