- Concurrency problems will not be picked by code reviews, best practices, programming to interfaces, TDD (You could but I am wonder who would be able to afford it), agile project management techniques etc.
- You must be prepared for your expected traffic and in fact you should write an email to your supervisors making them aware of the software limitation: We currently can handle x concurrent users.
- Formulas and calculations are OK for estimatives but that is just the theory. Do your hoework and be sure your software will be able to handle the expected traffic.
I have decided to use Liferay to show an example of a load test. You just need to download Jmeter unzip it and run jmeter from the bin folder, open then the file I pasted below and edit the "Http Request Defaults" to point to your Liferay instance. Then verify how your server will handle 100 concurrent users using a ramp up period of 10 seconds.
<?xml version="1.0" encoding="UTF-8"?>
<jmeterTestPlan version="1.2" properties="2.1">
<hashTree>
<TestPlan guiclass="TestPlanGui" testclass="TestPlan" testname="Test Plan" enabled="true">
<stringProp name="TestPlan.comments"></stringProp>
<boolProp name="TestPlan.functional_mode">false</boolProp>
<boolProp name="TestPlan.serialize_threadgroups">false</boolProp>
<elementProp name="TestPlan.user_defined_variables" elementType="Arguments" guiclass="ArgumentsPanel" testclass="Arguments" testname="User Defined Variables" enabled="true">
<collectionProp name="Arguments.arguments"/>
</elementProp>
<stringProp name="TestPlan.user_define_classpath"></stringProp>
</TestPlan>
<hashTree>
<ThreadGroup guiclass="ThreadGroupGui" testclass="ThreadGroup" testname="Thread Group" enabled="true">
<stringProp name="ThreadGroup.on_sample_error">continue</stringProp>
<elementProp name="ThreadGroup.main_controller" elementType="LoopController" guiclass="LoopControlPanel" testclass="LoopController" testname="Loop Controller" enabled="true">
<boolProp name="LoopController.continue_forever">false</boolProp>
<stringProp name="LoopController.loops">1</stringProp>
</elementProp>
<stringProp name="ThreadGroup.num_threads">100</stringProp>
<stringProp name="ThreadGroup.ramp_time">10</stringProp>
<longProp name="ThreadGroup.start_time">1289581012000</longProp>
<longProp name="ThreadGroup.end_time">1289581012000</longProp>
<boolProp name="ThreadGroup.scheduler">false</boolProp>
<stringProp name="ThreadGroup.duration"></stringProp>
<stringProp name="ThreadGroup.delay"></stringProp>
</ThreadGroup>
<hashTree>
<HTTPSampler guiclass="HttpTestSampleGui" testclass="HTTPSampler" testname="/web/guest" enabled="true">
<elementProp name="HTTPsampler.Arguments" elementType="Arguments" guiclass="HTTPArgumentsPanel" testclass="Arguments" enabled="true">
<collectionProp name="Arguments.arguments"/>
</elementProp>
<stringProp name="HTTPSampler.domain"></stringProp>
<stringProp name="HTTPSampler.port"></stringProp>
<stringProp name="HTTPSampler.connect_timeout"></stringProp>
<stringProp name="HTTPSampler.response_timeout"></stringProp>
<stringProp name="HTTPSampler.protocol"></stringProp>
<stringProp name="HTTPSampler.contentEncoding"></stringProp>
<stringProp name="HTTPSampler.path">/web/guest</stringProp>
<stringProp name="HTTPSampler.method">GET</stringProp>
<boolProp name="HTTPSampler.follow_redirects">true</boolProp>
<boolProp name="HTTPSampler.auto_redirects">false</boolProp>
<boolProp name="HTTPSampler.use_keepalive">true</boolProp>
<boolProp name="HTTPSampler.DO_MULTIPART_POST">false</boolProp>
<boolProp name="HTTPSampler.monitor">false</boolProp>
<stringProp name="HTTPSampler.embedded_url_re"></stringProp>
</HTTPSampler>
<hashTree>
<HeaderManager guiclass="HeaderPanel" testclass="HeaderManager" testname="HTTP Header Manager" enabled="true">
<collectionProp name="HeaderManager.headers">
<elementProp name="Accept-Language" elementType="Header">
<stringProp name="Header.name">Accept-Language</stringProp>
<stringProp name="Header.value">en-us,en;q=0.5</stringProp>
</elementProp>
<elementProp name="Accept" elementType="Header">
<stringProp name="Header.name">Accept</stringProp>
<stringProp name="Header.value">text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8</stringProp>
</elementProp>
<elementProp name="Keep-Alive" elementType="Header">
<stringProp name="Header.name">Keep-Alive</stringProp>
<stringProp name="Header.value">115</stringProp>
</elementProp>
<elementProp name="User-Agent" elementType="Header">
<stringProp name="Header.name">User-Agent</stringProp>
<stringProp name="Header.value">Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 GTB7.1</stringProp>
</elementProp>
<elementProp name="Accept-Encoding" elementType="Header">
<stringProp name="Header.name">Accept-Encoding</stringProp>
<stringProp name="Header.value">gzip,deflate</stringProp>
</elementProp>
<elementProp name="Accept-Charset" elementType="Header">
<stringProp name="Header.name">Accept-Charset</stringProp>
<stringProp name="Header.value">ISO-8859-1,utf-8;q=0.7,*;q=0.7</stringProp>
</elementProp>
</collectionProp>
</HeaderManager>
<hashTree/>
</hashTree>
<HTTPSampler guiclass="HttpTestSampleGui" testclass="HTTPSampler" testname="/html/js/barebone.jsp" enabled="true">
<elementProp name="HTTPsampler.Arguments" elementType="Arguments" guiclass="HTTPArgumentsPanel" testclass="Arguments" enabled="true">
<collectionProp name="Arguments.arguments">
<elementProp name="browserId" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">browserId</stringProp>
<stringProp name="Argument.value">firefox</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
</elementProp>
<elementProp name="themeId" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">themeId</stringProp>
<stringProp name="Argument.value">005E82_WAR_005E82theme</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
</elementProp>
<elementProp name="colorSchemeId" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">colorSchemeId</stringProp>
<stringProp name="Argument.value">01</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
</elementProp>
<elementProp name="minifierType" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">minifierType</stringProp>
<stringProp name="Argument.value">js</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
</elementProp>
<elementProp name="minifierBundleId" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">minifierBundleId</stringProp>
<stringProp name="Argument.value">javascript.barebone.files</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
</elementProp>
<elementProp name="t" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">t</stringProp>
<stringProp name="Argument.value">1274823175000</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
</elementProp>
</collectionProp>
</elementProp>
<stringProp name="HTTPSampler.domain"></stringProp>
<stringProp name="HTTPSampler.port"></stringProp>
<stringProp name="HTTPSampler.connect_timeout"></stringProp>
<stringProp name="HTTPSampler.response_timeout"></stringProp>
<stringProp name="HTTPSampler.protocol"></stringProp>
<stringProp name="HTTPSampler.contentEncoding"></stringProp>
<stringProp name="HTTPSampler.path">/html/js/barebone.jsp</stringProp>
<stringProp name="HTTPSampler.method">GET</stringProp>
<boolProp name="HTTPSampler.follow_redirects">true</boolProp>
<boolProp name="HTTPSampler.auto_redirects">false</boolProp>
<boolProp name="HTTPSampler.use_keepalive">true</boolProp>
<boolProp name="HTTPSampler.DO_MULTIPART_POST">false</boolProp>
<boolProp name="HTTPSampler.monitor">false</boolProp>
<stringProp name="HTTPSampler.embedded_url_re"></stringProp>
</HTTPSampler>
<hashTree>
<HeaderManager guiclass="HeaderPanel" testclass="HeaderManager" testname="HTTP Header Manager" enabled="true">
<collectionProp name="HeaderManager.headers">
<elementProp name="Accept-Language" elementType="Header">
<stringProp name="Header.name">Accept-Language</stringProp>
<stringProp name="Header.value">en-us,en;q=0.5</stringProp>
</elementProp>
<elementProp name="Accept" elementType="Header">
<stringProp name="Header.name">Accept</stringProp>
<stringProp name="Header.value">*/*</stringProp>
</elementProp>
<elementProp name="Keep-Alive" elementType="Header">
<stringProp name="Header.name">Keep-Alive</stringProp>
<stringProp name="Header.value">115</stringProp>
</elementProp>
<elementProp name="User-Agent" elementType="Header">
<stringProp name="Header.name">User-Agent</stringProp>
<stringProp name="Header.value">Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 GTB7.1</stringProp>
</elementProp>
<elementProp name="Accept-Encoding" elementType="Header">
<stringProp name="Header.name">Accept-Encoding</stringProp>
<stringProp name="Header.value">gzip,deflate</stringProp>
</elementProp>
<elementProp name="Accept-Charset" elementType="Header">
<stringProp name="Header.name">Accept-Charset</stringProp>
<stringProp name="Header.value">ISO-8859-1,utf-8;q=0.7,*;q=0.7</stringProp>
</elementProp>
</collectionProp>
</HeaderManager>
<hashTree/>
</hashTree>
<HTTPSampler guiclass="HttpTestSampleGui" testclass="HTTPSampler" testname="/image/company_logo" enabled="true">
<elementProp name="HTTPsampler.Arguments" elementType="Arguments" guiclass="HTTPArgumentsPanel" testclass="Arguments" enabled="true">
<collectionProp name="Arguments.arguments">
<elementProp name="img_id" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">img_id</stringProp>
<stringProp name="Argument.value">10303</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
</elementProp>
<elementProp name="amp;t" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">amp;t</stringProp>
<stringProp name="Argument.value">1289581656500</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
</elementProp>
</collectionProp>
</elementProp>
<stringProp name="HTTPSampler.domain"></stringProp>
<stringProp name="HTTPSampler.port"></stringProp>
<stringProp name="HTTPSampler.connect_timeout"></stringProp>
<stringProp name="HTTPSampler.response_timeout"></stringProp>
<stringProp name="HTTPSampler.protocol"></stringProp>
<stringProp name="HTTPSampler.contentEncoding"></stringProp>
<stringProp name="HTTPSampler.path">/image/company_logo</stringProp>
<stringProp name="HTTPSampler.method">GET</stringProp>
<boolProp name="HTTPSampler.follow_redirects">true</boolProp>
<boolProp name="HTTPSampler.auto_redirects">false</boolProp>
<boolProp name="HTTPSampler.use_keepalive">true</boolProp>
<boolProp name="HTTPSampler.DO_MULTIPART_POST">false</boolProp>
<boolProp name="HTTPSampler.monitor">false</boolProp>
<stringProp name="HTTPSampler.embedded_url_re"></stringProp>
</HTTPSampler>
<hashTree>
<HeaderManager guiclass="HeaderPanel" testclass="HeaderManager" testname="HTTP Header Manager" enabled="true">
<collectionProp name="HeaderManager.headers">
<elementProp name="Accept-Language" elementType="Header">
<stringProp name="Header.name">Accept-Language</stringProp>
<stringProp name="Header.value">en-us,en;q=0.5</stringProp>
</elementProp>
<elementProp name="Accept" elementType="Header">
<stringProp name="Header.name">Accept</stringProp>
<stringProp name="Header.value">image/png,image/*;q=0.8,*/*;q=0.5</stringProp>
</elementProp>
<elementProp name="Keep-Alive" elementType="Header">
<stringProp name="Header.name">Keep-Alive</stringProp>
<stringProp name="Header.value">115</stringProp>
</elementProp>
<elementProp name="User-Agent" elementType="Header">
<stringProp name="Header.name">User-Agent</stringProp>
<stringProp name="Header.value">Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 GTB7.1</stringProp>
</elementProp>
<elementProp name="Accept-Encoding" elementType="Header">
<stringProp name="Header.name">Accept-Encoding</stringProp>
<stringProp name="Header.value">gzip,deflate</stringProp>
</elementProp>
<elementProp name="Accept-Charset" elementType="Header">
<stringProp name="Header.name">Accept-Charset</stringProp>
<stringProp name="Header.value">ISO-8859-1,utf-8;q=0.7,*;q=0.7</stringProp>
</elementProp>
</collectionProp>
</HeaderManager>
<hashTree/>
</hashTree>
<HTTPSampler guiclass="HttpTestSampleGui" testclass="HTTPSampler" testname="/web/guest/home?p_p_id=58&p_p_lifecycle=1&p_p_state=normal&p_p_mode=view&p_p_col_id=column-1&p_p_col_count=1&saveLastPath=0&_58_struts_action=%2Flogin%2Flogin" enabled="true">
<elementProp name="HTTPsampler.Arguments" elementType="Arguments" guiclass="HTTPArgumentsPanel" testclass="Arguments" enabled="true">
<collectionProp name="Arguments.arguments">
<elementProp name="_58_redirect" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">_58_redirect</stringProp>
<stringProp name="Argument.value"></stringProp>
<stringProp name="Argument.metadata">=</stringProp>
<boolProp name="HTTPArgument.use_equals">true</boolProp>
</elementProp>
<elementProp name="_58_rememberMe" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">_58_rememberMe</stringProp>
<stringProp name="Argument.value">on</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
<boolProp name="HTTPArgument.use_equals">true</boolProp>
</elementProp>
<elementProp name="_58_login" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">_58_login</stringProp>
<stringProp name="Argument.value">nurquiza@sample.com</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
<boolProp name="HTTPArgument.use_equals">true</boolProp>
</elementProp>
<elementProp name="_58_password" elementType="HTTPArgument">
<boolProp name="HTTPArgument.always_encode">false</boolProp>
<stringProp name="Argument.name">_58_password</stringProp>
<stringProp name="Argument.value">test</stringProp>
<stringProp name="Argument.metadata">=</stringProp>
<boolProp name="HTTPArgument.use_equals">true</boolProp>
</elementProp>
</collectionProp>
</elementProp>
<stringProp name="HTTPSampler.domain"></stringProp>
<stringProp name="HTTPSampler.port"></stringProp>
<stringProp name="HTTPSampler.connect_timeout"></stringProp>
<stringProp name="HTTPSampler.response_timeout"></stringProp>
<stringProp name="HTTPSampler.protocol"></stringProp>
<stringProp name="HTTPSampler.contentEncoding"></stringProp>
<stringProp name="HTTPSampler.path">/web/guest/home?p_p_id=58&p_p_lifecycle=1&p_p_state=normal&p_p_mode=view&p_p_col_id=column-1&p_p_col_count=1&saveLastPath=0&_58_struts_action=%2Flogin%2Flogin</stringProp>
<stringProp name="HTTPSampler.method">POST</stringProp>
<boolProp name="HTTPSampler.follow_redirects">true</boolProp>
<boolProp name="HTTPSampler.auto_redirects">false</boolProp>
<boolProp name="HTTPSampler.use_keepalive">true</boolProp>
<boolProp name="HTTPSampler.DO_MULTIPART_POST">false</boolProp>
<boolProp name="HTTPSampler.monitor">false</boolProp>
<stringProp name="HTTPSampler.embedded_url_re"></stringProp>
</HTTPSampler>
<hashTree>
<HeaderManager guiclass="HeaderPanel" testclass="HeaderManager" testname="HTTP Header Manager" enabled="true">
<collectionProp name="HeaderManager.headers">
<elementProp name="Content-Type" elementType="Header">
<stringProp name="Header.name">Content-Type</stringProp>
<stringProp name="Header.value">application/x-www-form-urlencoded</stringProp>
</elementProp>
<elementProp name="Accept-Language" elementType="Header">
<stringProp name="Header.name">Accept-Language</stringProp>
<stringProp name="Header.value">en-us,en;q=0.5</stringProp>
</elementProp>
<elementProp name="Accept" elementType="Header">
<stringProp name="Header.name">Accept</stringProp>
<stringProp name="Header.value">text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8</stringProp>
</elementProp>
<elementProp name="Keep-Alive" elementType="Header">
<stringProp name="Header.name">Keep-Alive</stringProp>
<stringProp name="Header.value">115</stringProp>
</elementProp>
<elementProp name="User-Agent" elementType="Header">
<stringProp name="Header.name">User-Agent</stringProp>
<stringProp name="Header.value">Mozilla/5.0 (Macintosh; U; Intel Mac OS X 10.6; en-US; rv:1.9.2.12) Gecko/20101026 Firefox/3.6.12 GTB7.1</stringProp>
</elementProp>
<elementProp name="Accept-Encoding" elementType="Header">
<stringProp name="Header.name">Accept-Encoding</stringProp>
<stringProp name="Header.value">gzip,deflate</stringProp>
</elementProp>
<elementProp name="Accept-Charset" elementType="Header">
<stringProp name="Header.name">Accept-Charset</stringProp>
<stringProp name="Header.value">ISO-8859-1,utf-8;q=0.7,*;q=0.7</stringProp>
</elementProp>
</collectionProp>
</HeaderManager>
<hashTree/>
</hashTree>
</hashTree>
<ResultCollector guiclass="ViewResultsFullVisualizer" testclass="ResultCollector" testname="View Results Tree" enabled="true">
<boolProp name="ResultCollector.error_logging">false</boolProp>
<objProp>
<name>saveConfig</name>
<value class="SampleSaveConfiguration">
<time>true</time>
<latency>true</latency>
<timestamp>true</timestamp>
<success>true</success>
<label>true</label>
<code>true</code>
<message>true</message>
<threadName>true</threadName>
<dataType>true</dataType>
<encoding>false</encoding>
<assertions>true</assertions>
<subresults>true</subresults>
<responseData>false</responseData>
<samplerData>false</samplerData>
<xml>true</xml>
<fieldNames>false</fieldNames>
<responseHeaders>false</responseHeaders>
<requestHeaders>false</requestHeaders>
<responseDataOnError>false</responseDataOnError>
<saveAssertionResultsFailureMessage>false</saveAssertionResultsFailureMessage>
<assertionsResultsToSave>0</assertionsResultsToSave>
<bytes>true</bytes>
</value>
</objProp>
<stringProp name="filename"></stringProp>
</ResultCollector>
<hashTree/>
<CookieManager guiclass="CookiePanel" testclass="CookieManager" testname="HTTP Cookie Manager" enabled="true">
<collectionProp name="CookieManager.cookies"/>
<boolProp name="CookieManager.clearEachIteration">false</boolProp>
<stringProp name="CookieManager.policy">rfc2109</stringProp>
</CookieManager>
<hashTree/>
<ConfigTestElement guiclass="HttpDefaultsGui" testclass="ConfigTestElement" testname="HTTP Request Defaults" enabled="true">
<elementProp name="HTTPsampler.Arguments" elementType="Arguments" guiclass="HTTPArgumentsPanel" testclass="Arguments" testname="User Defined Variables" enabled="true">
<collectionProp name="Arguments.arguments"/>
</elementProp>
<stringProp name="HTTPSampler.domain">portal.sample.com</stringProp>
<stringProp name="HTTPSampler.port">443</stringProp>
<stringProp name="HTTPSampler.connect_timeout"></stringProp>
<stringProp name="HTTPSampler.response_timeout"></stringProp>
<stringProp name="HTTPSampler.protocol">https</stringProp>
<stringProp name="HTTPSampler.contentEncoding"></stringProp>
<stringProp name="HTTPSampler.path"></stringProp>
</ConfigTestElement>
<hashTree/>
<ResultCollector guiclass="TableVisualizer" testclass="ResultCollector" testname="View Results in Table" enabled="true">
<boolProp name="ResultCollector.error_logging">false</boolProp>
<objProp>
<name>saveConfig</name>
<value class="SampleSaveConfiguration">
<time>true</time>
<latency>true</latency>
<timestamp>true</timestamp>
<success>true</success>
<label>true</label>
<code>true</code>
<message>true</message>
<threadName>true</threadName>
<dataType>true</dataType>
<encoding>false</encoding>
<assertions>true</assertions>
<subresults>true</subresults>
<responseData>false</responseData>
<samplerData>false</samplerData>
<xml>true</xml>
<fieldNames>false</fieldNames>
<responseHeaders>false</responseHeaders>
<requestHeaders>false</requestHeaders>
<responseDataOnError>false</responseDataOnError>
<saveAssertionResultsFailureMessage>false</saveAssertionResultsFailureMessage>
<assertionsResultsToSave>0</assertionsResultsToSave>
<bytes>true</bytes>
</value>
</objProp>
<stringProp name="filename"></stringProp>
</ResultCollector>
<hashTree/>
<ResultCollector guiclass="GraphVisualizer" testclass="ResultCollector" testname="Graph Results" enabled="true">
<boolProp name="ResultCollector.error_logging">false</boolProp>
<objProp>
<name>saveConfig</name>
<value class="SampleSaveConfiguration">
<time>true</time>
<latency>true</latency>
<timestamp>true</timestamp>
<success>true</success>
<label>true</label>
<code>true</code>
<message>true</message>
<threadName>true</threadName>
<dataType>true</dataType>
<encoding>false</encoding>
<assertions>true</assertions>
<subresults>true</subresults>
<responseData>false</responseData>
<samplerData>false</samplerData>
<xml>true</xml>
<fieldNames>false</fieldNames>
<responseHeaders>false</responseHeaders>
<requestHeaders>false</requestHeaders>
<responseDataOnError>false</responseDataOnError>
<saveAssertionResultsFailureMessage>false</saveAssertionResultsFailureMessage>
<assertionsResultsToSave>0</assertionsResultsToSave>
<bytes>true</bytes>
</value>
</objProp>
<stringProp name="filename"></stringProp>
</ResultCollector>
<hashTree/>
</hashTree>
</hashTree>
</jmeterTestPlan>
There are a few important things you need to know to keep a Jmeter test growing and usable for your needs.
- Thread Group: Besides simulating a specific number of users do use a ramp up period that makes sense. Any system even Google can be a victim of denial of service so do test real non-attack case scenarios. This means it is unlikely (if not practically impossible) the 100 users end up hitting your server at the same time. As you see I have distributed the load in 10 seconds.
- See how I include pulling resources like the logo besides hitting the home page and trying to login into the website. Resources are cached so it is up to you to decide if they should be included in a stress test. For example if you launched a marketing campaign and your users will be new all resources will be downloaded. Contrary to the common core developers believe front end code is usually the bottleneck in many web applications
- Always use a "Default Requests Defaults Config Element" so you can easily use the same test against your local environment and real servers (Be sure you do not hit real production during high traffic hours or you will end up affecting real users)
- Look into the server logs looking for exceptions
- Think about simulating cases where local sample data is affected by several different users. In this case I have added only one user but you can use expressions and build different users on the fly or harcode them in different threads. Analyze the data after running the tests looking for inconsistencies.
- Use a Cookie Manager so you maintain the session between requests
- Run the test first with one user and analyze all responses. There are several views, the "View Results Tree Listener" is your friend to see request and response of each request.
- Use a "View Results in Table Listener" for a quick inspection about response delays. It helps your identify botlenecks.
- Use Graph results to get statistics. Be sure you understand what average, median and deviation is. Use a larger user base for example 1000 users distributed through 2 minutes or a little more to be sure the statistics have a better meaning. The more samples the better as the server will be warmed up simulating better those enjoying a large uptime
- Use a random timer after each request. My example does not include them but you can easily add it from Menu | Edit | Add. That ensures a closer to reality scenario. A user will not be hitting every second your website.
- Simulate a denial of service attack and see if you are prepared for it in the case you are not handling that at firewall layer (recommended)
- There is so much more you can do including creating the test cases from a normal browser navigation using a Proxy
The SDLC is a long circle and testing is an indispensable part of it. Stress tests or load tests are important, way more than what many developers think. Take control and stress the application, don't let the application stress yourself.
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