If a large amount of sequential prefetching is occurring, what can be done to improve efficiency?

Given the following output:

Which Explain procedure can be used to find the most expensive SQL statement in terms of CPU
cost over a period of time?

A database named TEST was created and two buffer pools named BP_GENERAL and
BP_AUDITING were created as follows:

The majority of the database tables were created in table space TS1, while one large table was
created in table space TS2. A set of triggers thatThe majority of the database tables were created
in table space TS1, while one large table was created in table space TS2. A set of triggers that
would populate the table in table space TS2 each time changes were made to the database were
then defined and the database was put into production.
At first, ad-hoc queries performing random I/O against the table in table space TS2 ran fine, but
performance has gotten worse as the table has gotten larger. What should be done to improve
query performance?

A storage group named MED_SG was created as follows: CREATE STOGROUP med_sg ON
?db2fs1? ?db2fs2? ‘/db2fs3’ Then, a table space named TS1 was created in the storage group
and two tables (TAB_A and TAB_B) were created in the TS1 table space. Four months later, a
DBA discovered that 90% of the space that had been allocated to the MED_SG storage group had
been consumed. So, more space was added to the storage group by executing the following
command: ALTER STOGROUP med_sg ADD ?db2fs4? ALTER STOGROUP med_sg ADD
?db2fs4 Shortly afterwards, queries against tables in the TS1 table space began to run slower.
Which statement should be executed to correct the performance problem?

A query against the system catalog revealed that data for a table named SALES in a partitioned
database is distributed as follows:

What can be done to improve the performance of a query that joins SALES and DATE_DIM tables
(where SALES is a fact table and DATE_DIM is a dimension table) using the DATE_ID column?