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Locating Bottlenecks in Your Code with the Event ProfilerAn Oracle JDeveloper How To Document
IntroductionOracle JDeveloper has three built-in profilers that can help you fine-tune your Java application. The profilers monitor Java programs as they run, and collect information about the events and memory consumption during the execution. Using the profilers you can find bottlenecks and memory leaks resulting in improved performance for your application. In this short how-to we focus on the event profiler. This profiler provides information about the events taking place in your application when it runs. Configuring the Event profilerTo configure the behavior of the event profiler, in JDeveloper 10.1.2 double click your project to go to the project properties and look under the profiler->events node. In JDeveloper 10.1.3 preview these settings are under the tools->preferences menu option.
Profiling with Your own EventsLet's see an example of how using the event profiler we can pin-point a problematic area in our code. We'll use
this class to test our performance.
public
static
void
main
(
String
[]
args
)
throws
SQLException
{
for
(
int
i
=
0
;
i
<
10
;
i
++
)
{
profilerTest
myP
=
new
profilerTest
()
;
//TODO add some emp functionality
myP
.
printNumEmp
()
;
}
}
Running it we see the process takes about 2.5 seconds, which is too much time for us. So we want to check what parts of the code are slow performing. We'll define two profiler events in our code to track the getConnection method and then the execution of the select statement. Adding an event is quite simple. Firs add the
JDeveloper SDK library to your project's libraries. Then in your class's code add
import oracle.jdeveloper.profiler.ProfilerAPI;
In our code we add two events:
private
void
printNumEmp
()
throws
SQLException
{
int
connection_event
=
ProfilerAPI
.
startEvent
(
CON_EVENT_ID
,
"Connecting to DB"
)
;
//starting the connection event
Connection
myConn
=
getConnection
()
;
ProfilerAPI
.
endEvent
(
connection_event
)
;
//ending connection event
int
select_event
=
ProfilerAPI
.
startEvent
(
SELECT_EVENT_ID
,
"Selecting data"
)
;
//starting select event
Statement
myStt
=
myConn
.
createStatement
()
;
ResultSet
results
=
myStt
.
executeQuery
(
"select count(*) from emp"
)
;
results
.
next
()
;
System
.
out
.
println
(
results
.
getString
(
1
))
;
ProfilerAPI
.
endEvent
(
select_event
)
;
//ending select event
results
.
close
()
;
myStt
.
close
()
;
myConn
.
close
()
;
}
To make sure we get a clearer picture of the events in the results page we can configure the profiler to display meaning full names.
Event Profiler Configuration Now when we run the profiler we see more detailed information. A good thing to do here is to order the results by the duration in a descending order - this way we can see that the connection events is taking a lot of time and happens frequently. Maybe we can make our program run faster if we'll try and reuse connections instead of creating them from scratch each time. 
Event Profiler Results The profiler API gives you further control with additional methods that allow you for example to specify a comment to an event (addComment), or add the stack to a comment (addStackToComment). Adding this type of information can help you understand the profiler's results more easily when running longer pieces of code. ConclusionVery often the performance of a program can be greatly improved by fixing a small piece of code that gets executed repeatedly. The event profiler in JDeveloper can help you locate the frequency and duration of execution for various parts of your code. Identifying these areas of your code helps you pay special attention to them when tuning to get the most bang-for-the-buck while tuning. |
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