Query Performance PTFs

["Garcia Rich (SYS1RXG)" <sys1rxg@xxxxxxx>]

Has anyone attempted to load the following with a large database and if so
can you let me know if the change is made on the first IPL or every IPL.

Query Performance PTFs 

A set of PTFs were recently made available that can have a direct impact on
query performance. These new PTF's enable DB2 UDB for AS/400 to create
indexes (also known as logical files or access paths) with a larger logical
page size (64K). Most AS/400 indexes today have a logical page size of only
4K or 8K. This larger page size makes indexes more attractive to the query
optimizer and allows the database paging to be more efficient on a query.
For example, one customer after applying the PTF's saw a 40% decrease in run
time for a set of 15 queries that they frequently run. 

The larger page size will only be used on indexes created over tables
created with SQL. Thus, database files created with DDS will not be able to
benefit from this larger index page size. The 64K logical page size will be
used automatically for any index that is created over an SQL-created table -
this includes both SQL-created indexes and indexes created for constraints. 

Since a larger page size is not available for indexes created with an access
path size of *MAX4GB, DB2 UDB for AS/400 will attempt to rebuild existing
indexes over SQL tables as *MAX1TB indexes. You should be aware that DB2 UDB
is also not able to utilize the larger logical page size when an identical
*MAX1TB index (built with a smaller page size) already exists over the table
- in this case, the database manager has to share the existing index. 

Thanks.
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