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

WebSphere z/OS - DB2 z/OS V8 - Servlet workload
JCC type 2 vs. JCC type 4 in local environment
WebSphere
V502
servlet
WebSphere
V502
servlet
z/OS 1.3
JCC
T2
1.8.36
z/OS 1.3
JCC
T4
1.8.36
DB2 V8
for z/OS
T
C D
P/ D
I F
P
DB2 V8
for z/OS
Figure 7-8 DB2 Universal Type 2 Driver vs. DB2 Universal Type 4 Driver
Using the setup with the DB2 Universal Type 4 Driver (DRDA), the throughput is reduced by
51% when compared to the Type 2 Driver RRSAF connection to DB2. The Type 2 Driver
communicates with DB2 via cross-memory calls where the Type 4 Driver uses the TCP/IP
stack.
The setup with the Type 4 Driver is not that unusual. If access to several DB2 subsystems in
the same LPAR is needed, you will need the Type 4 Driver as this is not supported by the
Type 2 Driver with an RRSAF connection.
This measurement was executed using JDK 1.3.1. The performance of the setup with the
Type 4 Driver improves with JDK 1.4.2.
JDK 1.4.2 has seen the JIT compiler optimized, and the Java TCP/IP implementation
improved. A separate performance comparison is shown in Figure 7-9.
Notice that JDK versions go in pairs with WAS versions:
► WAS 5.0.2 and JDK 1.3.1
► WAS 5.1.0 and JDK 1.4.2
296 DB2 UDB for z/OS Version 8 Performance Topics
Trans/sec - higher is better
350
300
250
200
150
100
50
0
ITR
-51%
JCC type 2
JCC type 4