Web Performance Tips

Description

Is there any pre-requisites, before start recording the URLs in Web Performance Test Studio.

Solution

Yes, following configurations has to be done.

1. Set "Every time check the server" option in cache control.

2. Clear Browser Cache and Cookies.

3. Check whether proxy settings has been properly set.

4. Check whether you have configured the appropriate port settings in the Web Browser, by clicking the "Record --> Start Record" button which   displays the Proxy Setup UI.

5. In the Proxy Setup UI, configure the Server Port (if required). Default value is 8091. If you are changing the server port, ensure that you are changing the same in Recorder Settings screen.

6. The default browser name is displayed in the Default Browser field.

7. To setup the appropriate port settings in the Web Browser, click the Setup button which automatically takes care of setting up the port details in the Web Browser.

8. Now, you can click the Launch & Start Record button to launch the browser and start recording the transactions (urls) in the Web application. If you have already launched the browser, you can click the Record button.

9. Check the Http protocol version supported in the server.

Description

For example, Virtual IP's configured in playback engine are in the range of 1.2.3.1 - 1.2.3.254 and your actual network has a range of 192.168.12.1 - 192.168.12.254, and your playback engine is on machine with ip 192.168.12.10.

In order for the web server to route network packets to the playback machine which has the virtual ip configured you need to add route configuration in the web server machine. 

Solution

 Execute the route add commands as indicated below:

Windows System
 

route add 1.2.3.0 mask 255.255.255.0 192.168.12.10

Run this command to add a route to the destination 1.2.3.0 with the subnet mask of 255.255.255.0 with a gateway address of 192.168.12.10

** You should have administrator previleges to execute the above command.

Linux System

route add -net 1.2.3.0 gw 192.168.12.10 netmask 255.255.255.0

Run this command to add a route to the destination 1.2.3.0 with the subnet mask of 255.255.255.0 and  gateway address of 192.168.12.10

** You should login as super user to execute the above command.

Description

How do I determine the number of virtual users to be simulated for load testing a Web application

Solution

Determine your web-site characteristics

1. Transactions per month (TPM)
2. Average User time per transaction (TPS)

Step 1 :First, Determine the Transactions Per Second (TPS):

            TPS=TPM/((number of business days)* (number of hours a day)*(60*60))

STEP 2 :Determine the number of Virtual Users required:

            TPS X Avg User time Per Transaction = Number of  VU's

Example:

6,000,000 transactions per month
The average user time per transaction is 60 seconds.

417 = (6,000,000*60)/(20*12*60*60*)

Number of Virtual Users's = 417.

Description

The parameterization done for URL parameters (GET or POST data) for a specific URL can it be resused for other similar URLs in the selected business case.

Solution

Yes, you can reuse the parameterization for other similar URLs in a business case. You can choose the check box "Use this configuration for similar URLs in this businesscase" from the top right hand-side panel of Value Substitution UI of Configure Parameters screen. This option is used to reuse the parameterization for similar URLs in the selected business case.

Description

In Windows OS, the TCP-IP system has a parameter that controls the maximum port number used when an application requests any available user port from the system. Ports are allocated between the values of 1024 and 5000 inclusive. During a  test, if we exceed this limit, we get the address in use exception.

Solution

To change this, modify the following Registry values under the key HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Services\Tcpip\Parameters:

MaxUserPort       = dword:00004e20 (20,000 decimal)

Set the MaxUserPort to a larger number and reboot once the setting is changed.

Description

This may be due to the no. of files that can be opened concurrently.

Solution

To increase the file descriptors in Linux, execute the following command in su mode.

echo 65535 > /proc/sys/fs/file-max

Description

When the server monitor is not able to open a telnet session with the remote machine, Connect Exception would be printed in the logs. In this case, the data would not be collected.

Solution

Ensure that the telnet server is running in the remote machine.

Description

When you delete a business case associated with a profile and if the profile is not updated, then you will not be able to execute the test case.

Solution

When you delete a business case, update the profile in which the business case is associated. Then, execute the test case.

Description

Connection refused" errors occur due to queuing  limit of connection requests in Windows.  

Solution

Windows NT 4.0 Workstation and Windows 2000 Professional are limited to a 5 pending connection requests. Windows NT 4.0 Server and Windows 2000 Server can go up to 200 connections.

Description

While using Linux Server Monitoring using SSH protocol, the reports are not generated. The reports page displays as "No data to display".

Solution

While using Linux Server Monitoring through SSH Protocol, the file sshtools-j2ssh-0.0.4-alpha-bin.tar.gz has to be download from prdownloads.sourceforge.net and extracted under <QEngine-Home>/jars directory.  After extraction, the following jars should be present under <QEngine-Home>/jars directory.

1.jaxb-rt-1.0-ea.jar

2.log4j-1.2.6.jar

3.sshtools-j2ssh-0.0.4-alpha.jar

Now, run the Linux Server Monitoring using SSH protocol, the reports will be generated.