IT27018: LONG CHECKPOINT BLOCK MAY OCCUR WHEN USING MAX_FILL_DATA_PAGES WITH TABLE PAGES INCORRECTLY MARKED AS HAVING SPACE

APAR status

• Closed as fixed if next.

Error description

• When the onconfig parameter MAX_FILL_DATA_PAGES is set to one
  pages within tables using variable length row sizes are marked
  full when the free space remaining on the page is less than the
  lower of these conditions :
  - 10% of the maximum page free space
  - the average size of rows on the page
  
  If the average row size on the page is less than 10% of the
  maximum page free space then the page will not be considered
  full even when more than 90% of available space is used.
  
  A problem may arise when the average row size is more than 10%
  of the maximum page free space and the actual page free space is
  between the 10% value and the average row size. An attempt to
  insert a row with size greater than the actual free space on the
  page will fail but the page will not be marked as full. If there
  are many such rows to be inserted and having similar sizes then
  the same pages will be selected over and over again. Such
  behaviour may lead to the start of checkpoint processing being
  delayed for extended periods of time.
  

Local fix

• Set the onconfig parameter to 0 MAX_FILL_DATA_PAGES and restart
  the engine. Then run 'oncheck -cD <dbname>:<table> -y' for each
  table in each database that uses variable length row sizes. For
  each page that does not have sufficient space for a row of
  maximum size the bitmap will be updated to mark the page as
  full.
  

Problem summary

• ****************************************************************
  * USERS AFFECTED:                                              *
  * Users of IDS 11.70.xC9 and earlier versions.                 *
  ****************************************************************
  * PROBLEM DESCRIPTION:                                         *
  * With variable row length and MAX_FILL_DATA_PAGES pages might *
  * forever offer room that never satisfies any new row,         *
  * potentially causing long checkpoint blocks.                  *
  ****************************************************************
  * RECOMMENDATION:                                              *
  ****************************************************************
  

Problem conclusion

• Fixed in IDS 11.70.xC9W2.
  

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

Applicable component levels