These two APARs address unexpected table space growth due to internal DB2 algorithms.
· PM77236 – space growth in V9 and V10 with row-level-locking and small MAXROWS value
Under the following combination, the segmented TS can grow:
(1) The TS object is a Classic segmented TS
(2) Row-Level-Locking is in affect
(3) Multiple units-of-work are updating the same page at the same time and the total RIDs aready reached the MAXROWS limit which in this customer case is 9 rows in them.
(4) Some changes must be affecting holes to shrink or to delete row in combination with record length growth
· PM80804 – LOB space growth in V10 due to old read claim LRSN
This APAR harkens back to a long standing DB2 best practice that DB2 Catalog and Directory objects should be segregated in their own pool away from user data. In this case a user LOB table space was growing. This was due to a seemingly old value for read claim lrsn for the buffer pool. LOB space reuse is tracked at buffer pool level using oldest read claim LRSN. Any objects using a 32k buffer pool are considered when calculating the oldest reader LRSN. Our commit scope and space use for catalog objects is particular to those objects, so long running units of work can negatively our space reuse there.