Common Performance Issues and in different phases

• Slow transactional response with or without application workload
• Failure to meet the processing rate, for example, 1,000 submitted orders per second
• Failure of the application to serve the required number of concurrent users
• Non-responding application under workload
• Transactional errors during application workload, which could be reported by application users or seen in the application log files
• Mismatch between application workload and resource utilization, for example, CPU utilization is 90 percent with a few users or memory utilization is 70 percent even during no user activity
• Abnormal application behavior under certain conditions, for example, the application's response slows down daily at midnight
• All other aspects of application failure to meet functional or nonfunctional requirements under workload

Classifying performance issues by the discovery phase 

• If we classify performance issues according to their discovery time in the typical waterfall development process, we can see the following main categories:  
• Requirement issues, mainly related to a missing or unrealistic service-level agreement 
• Design issues, where the design is the root cause of these issues 
• Development issues, such as not following best coding practices, or bad cod- 
• ing quality 
• Testing issues, such as missing or bad quality performance testing 
• Operational issues, which are mainly related to production environment- 
• specific issues, such as the database size or newly introduced system, and so on 

Key Steps to a Performance Testing Strategy

Some Tips and Techniques

1) Load requirements should be based on peak second ,instead of peak day and divide by 8hours or something .

2) Things to identify performance test cases
       1)Critical to application/project
       2) Create more load on resources
       3) should be common functionality
       4) based on previous history
       5) Nature of applicaiton/project

3)

Response Time Breakdown

Response time - We have three types of response times

1) End to End
2) Server Response time which tool provides
3) Client side metrics

In end to end response time below are the steps :

1) DNS lookup
2) Connection
3) SSL or Firewall
4) Load Balancer
5) Webserver
6) Appserver
7) DB server

Garbage Collection and Tuning

Garbage Collection : Destruction of unnecessary objects mechanism is called Garbage collection.Garbage collector is responsible for this mechanism.

Objects are eligible for GC: 

1) Whenever object does not have any reference variable.
2) Programmer can make object is eligible for GC if it is no longer required.

Methods to make object eligible for GC:

1) Nullifying Reference Variable
2) Reassigning reference variable  to another object - so old object eligible for garbage collection
3) Objects created inside a method
4) Island of Isolation

Methods JVM to Run GC:

1) System class method - system.gc();
2) By using Runtime class

JVM Thread Dump Analysis Part 1

JVM & Thread Dump Fundamentals:


Thread Dump : Thread Dump is a snapshot at given time which provides complete listing of all threads created in java.

Thread Dump Generation Tools :

1) OS Native Command (kill -3<pid>)
2) JDK jstack utility
3) Java visual VM
4) Oracle Weblogic Admin Console

1 ) ps -ef  | grep java - this will list all java processes
2) jstack pid | more


If JVM is healthy then we can use JDK jstack or java visual JVM, else we can use OS Native command.OS native command always better to avoid further performance problems.

In weblogic under servers -monitoring - threads

hogging threads- A thread executing same requesting more than 5 sec. - This option is available in web logic console.

How to Analyse Thread dump

1) First verify healthy and non healthy threads  - for ex stuck thread might be unhealthy thread - we need to identity pattern instead of analyzing all threads.

2) Verify Heap Size

3)

Peoplesoft Scripting With loadrunner

Previously LR has separate protocol for People soft. Now oracle web supports people soft protocol.But web(HTTP/HTML) protocol also supports people soft scripting.

Things to do before scripting :

1) In recording options make sure Aceept Encoding and Accept Language are checked under headers








2) In recording options under correlation rules check peoplesoft.