Databases Reference
In-Depth Information
Client/Application Server
Application/
Application Framework
Database Server
Database Driver/
Provider
Database
Java and
.NET only
Runtime
Environment
Environment
Layers
Operating System
Operating System
Network
Software
Network
Software
Hardware
Hardware
Network
Figure 4-1
Environment layers
The influence of the environment can be significant, as shown by the follow-
ing real-world example. A major business software company thoroughly tested a
new database application on a local area network (LAN), and performance was
acceptable according to all the benchmarks that were run. Surprisingly, when the
database application was deployed in the production environment, which
involved network travel over a wide area network (WAN), overall response time
dropped by half. Puzzled about the performance, developers placed the actual
machines used in the testing environment into the production environment;
performance was still compromised. After troubleshooting the database applica-
tion in the production environment, the developers discovered that the network
traffic over the WAN passed through multiple network nodes with lower MTUs,
which caused network packet fragmentation. See the section, “Avoiding Network
Packet Fragmentation,” page 98, for more information about packet fragmenta-
tion.
