Number of physical writes of temporary
pages 
Number of physical writes of temporary pages: <count>
When
temporary
data
pages are generated to build (buffer) sets of results (in JOINS or ORDER
BY statements, for example), the
data cache is not
large enough for the temporary pages, and they have to be displaced to the
data area.
However, these pages must be exported out of the data area again for the
further processing of the SQL statement.
Find the statement that causes these large amounts of (buffer) results to be created, and check the access strategies for this statement.

For information on creating optimized SQL
statements, see
Optimizer:
SAP DB 7.4..