DB2 UDB for z/OS Version 8 Performance Topics - IBM Redbooks

Use DB2 Connect when a high amount of client connections is expected, for example, from
applets, in its quality as connection pool/connection concentrator. The measured overhead,
shown in Figure 7-13, is about 2%.
Where possible, use SQLJ. Throughput is higher as well on the server as on the requester
with SQLJ. Static SQL is faster than dynamic SQL, because at run time only the authorization
for packages and plans must be checked prior to the execution of the program. In contrast to
that, dynamic SQL statements require the SQL statements to be parsed, table and view
authorization to be checked, and the access path to be determined. Besides better
performance, SQLJ offers availability and usability benefits over JDBC:
► Less and easier code, easier to maintain
► Authorization on package level
► Easier deployment with the fully portable serialized profile when using the Universal Driver
if compared to the old driver.
Balancing features of JCC with WebSphere V5.1.1 AIX - DB2 for z/OS V8
Starting from the GA version of DB2 Universal Driver FixPak 10, DB2 has introduced
connection concentrator and sysplex workload balancing features for all Java type 4
connections to DB2 for z/OS servers. These two new features are built upon the JCC global
object pooling architecture, and are similar in functions to DB2 Connect's connection
concentrator and sysplex support.
The objective of these measurements is to evaluate the overhead of reusing JCC transports
with connection concentrator and sysplex workload balancing enabled, and compare it to the
overhead of DB2 Connect and JCC T2 driver.
The IRWW workload was run with the JCC T4 configuration shown in Figure 7-14.
IRWW
Workstation
IRWW
Workload
Driver
Figure 7-14 JCC T4 configuration for balancing options
Connection concentrator and sysplex workload balancing are two separate JCC features.
This is different from DB2 Connect where connection concentrator must be enabled before
you can exploit sysplex load balancing and failover routing at the transaction boundary. It is
possible to enable connection concentrator or sysplex workload balancing in the JCC data
source custom properties.
300 DB2 UDB for z/OS Version 8 Performance Topics
WebShpere
AIX zSeries
J
C
C
T
4
LPAR D7
DB8A
LPAR D8
DB8B