Databases Reference
In-Depth Information
•
Applications that return a large result and a single row, such as purchase
order applications. For example, this might be a
Select
statement that
retrieves one row with 30 columns.
•
Applications that return a small result and many rows, such as a report with
a list of part numbers—often referred to as drill-down applications. For
example, this might be a
Select
statement that retrieves 100 rows with one
column.
•
Applications that return a large result and many rows, such as reporting
applications—often referred to as business intelligence applications. For
example, this might be a
Select
statement that retrieves 10,000 rows with 30
columns.
The performance issues you might see in an application can depend on the
amount of data your application requests. The more data an application
requests, the more data the database driver must retrieve from the database and
return to the application. More data can equate to a longer response time. The
first three types of applications in the preceding list may have many of the same
performance issues. The performance issues are likely caused by poorly tuned
database middleware because in these types of applications,
most of the response
time is spent in the database middleware
.
For business intelligence applications (applications that report, analyze, and
present data), you will see different performance issues depending on whether
the application is generating a report or doing expensive online analytical pro-
cessing (OLAP) analysis. In the case of a report, most of the response time is
spent in the database middleware. For OLAP, most of the response time is spent
in the database, not the middleware.
In this chapter, we focus on database drivers—what they are, what they do,
and how they affect performance. See Chapter 4, “The Environment: Tuning for
Performance,” for information about how your runtime environment, network,
operating system, and hardware can affect performance.
A
database driver
is a software component that an application uses on demand
to gain access to a database using a standards-defined method.
Database drivers are a key component of your database application deploy-
ment, and they can affect the performance of your database application. You
might be thinking that a driver is a driver is a driver. But that isn't true.
