JMeter―Using the Transaction Controller

Apache JMeter is a performance testing tool written in Java and supports many operation systems. Controllers are main part of JMeter and they are useful to control the execution of JMeter scripts for load testing.  Logic controllers (e.g., Transaction Controller) also provide runtime scopes for JMeter test elements (read [9] for details).

For example, you can use Transaction Controller to get the total execution time of a transaction (i.e., an end-to-end scenario) which might include the following transaction steps:

Login → Compute Details → Billing Metrics → Back to Dashboard → Logout

Watch this video on YouTube for more details of Transaction Controller.

Controllers

JMeter has two types of Controllers:^[3]

• Samplers
• Can be used to specify which types of requests to be sent to a server
• You may add Configuration Elements to these Samplers to customize your server requests.
• Examples of Samplers include, but not limited to:
• HTTP Request
• FTP Request
• JDBC Request
• Java Request
• SOAP/XML-RPC Request
• WebService (SOAP) Request
• LDAP Request
• LDAP Extended RequestAccess Log Sampler
• BeanShell Sampler
• Logic Controllers
• Can be used to customize the logic that JMeter uses to decide when to send requests
• For these requests, JMeter may randomly select (using Random Controller), repeat (using Loop Controller), interchange (using Interleave Controller) etc.
• The child elements of a Logic Controllers may comprise 
• Samplers
• Configuration Elements
• Logic Controllers
• Examples of Logic Controllers include, but not limited to:
• Transaction Controller
• Simple Controller
• Loop Controller
• Interleave Controller
• Random Controller
• Random Order Controller
• Throughput Controller
• Recording Controller

In this article, we will focus mainly on Transaction Controller which may be used to

• Generate a “virtual” sample to measure aggregate times of all nested samples

Option: "Generate Parent Sample"

When "Generate parent sample" in Transaction Controller is

• Checked 
• Only Transaction Controller virtual sample will be generated and  all other Transaction Controller's nested samples will not be displayed in the report

• Unchecked 
• Additional parent sample (i.e. Transaction Controller virtual sample) after nested samples will be displayed in the report

Option: "Include Duration of Timer and Pre-Post Processors in Generated Sample"

Each Sampler can be preceded by one or more Pre-processor element, followed by Post-processor element. There is also an option in Transaction Controller to include and/or exclude timers, pre and post processors execution time into/from virtual samples.

When the check box "Include duration of timer and pre-post processors in generated sample" is

• Checked
• The aggregate time includes all processing within the controller scope, not just the nested samples
• Unchecked
• The aggregate time includes just the nested samples; however, excludes all pre-post processing within the controller scope

References

1. How to use Apache JMeter "Transaction Controller" to get total time of execution
2. 12th JMeter Training Video - Transaction Controller
3. Apache JMeter Book
4. Configuration Elements (Apache JMeter)
5. Transaction Controller (Apache JMeter)
6. Using JMeter's Transaction Controller
7. JMeter: How to Turn Off Captive Portal from the Recording Using Firefox (Xml and More)
8. JMeter—Use Extractors (Post-Processor Elements) for Correlation (Xml and More)
9. JMeter Scoping Rules - The Ultimate Guide (BlazeMeter)