Databases Reference
In-Depth Information
after the data in the production environment? Did the benchmark test the
same number of users as is seen in the production environment? Was the
same version of the database driver used in both environments? Were the
drivers configured the same in both environments? Did the test environment
use all the same operating systems for clients and database servers as the pro-
duction environment?
•
Are there any connection option settings in the driver that could be changed
to improve performance?
Thinking Through the Issue
Let's think about what we know:
•
The application was benchmarked in a test environment before being
deployed, and performance was acceptable.
•
The application is using distributed transactions, which can slow down per-
formance because of the logging and network round trips needed to com-
municate between all the components involved in the distributed
transaction.
•
The connection string used in the benchmark does not show that the appli-
cation is using data encryption, which is a requirement for all of this com-
pany's applications.
To solve this issue, we need to look at the test and production environments
and see if there are any differences. The main question in this case study is why
the test environment shows better performance. The performance issue is caused
by data encryption. We discussed the effect that data encryption has on perfor-
mance in Chapter 2, “Designing for Performance: What's Your Strategy.” To sum-
marize, encryption is performed on each byte of data being transferred, which
means slower network throughput.
Another issue to point out in this case study is that the benchmark did not
duplicate the production environment. See “Reproduce the Production
Environment,” page 246, to read about how important it is to do this when
benchmarking.
The Resolution
As we discussed in “Data Encryption across the Network,” page 86, performance
penalties go along with using data encryption, and often there is little you can do
about it. If your database system allows one connection that uses data encryption
