jmeter and apachetop - why I see different values? - apache

Probably explanation is simple - but I couldn't find answer to my question:
I am running jmeter test from one VM (worker) to another (target). On worker I have jmeter with 100 threads (100 users). On target I have API that runs on Apache. When I run "apachetop -f access_log" on target, I see only about 7 req/s.
Can someone explain me, why I don't see 100 req/s on target?
In test result in jmeter I see always 200 OK, so all request are hitting the target, and moreover target always responds. So I am not dropping any requests here. Network bandwidth between machines is 1G. What I am missing here?
Thanks,
Daddy

100 users doesn't necessarily mean 100 requests per second, even more, it is highly unlikely.
According to JMeter glossary:
Elapsed time. JMeter measures the elapsed time from just before sending the request to just after the last response has been received. JMeter does not include the time needed to render the response, nor does JMeter process any client code, for example Javascript.
Roughly, if JMeter is able to get response from server in 1 second - you will get 100 requests/second. If response time will be 2 seconds - throughput will be 50 requests/second, etc, response time 4 seconds - 25 requests/second, etc.
Also JMeter configuration matters. If you don't provide enough loops you may run into a situation where some threads already finished and some are not even started. See JMeter Test Results: Why the Actual Users Number is Lower than Expected article for more detailed explanation.

Your target load = 100 threads ( you are assuming it should generate 100 req/sec as per your plan)
Your actual load = 7 req / sec = 7*3600 / hour = 25200
Per thread throughput = 25200 / 100 threads = 252 iterations / thread / hour
Per transaction time = 3600 / 252 = 14.2 secs
This means, JMeter should be actually sending each request every 14 secs per thread. i.e., 100 requests for every 14.2 secs.
Now, analyze your JMeter summary report for the transaction timers to find out where the remaining 13.2 secs are being spent.
Possible issues are
1. High DNS resolution time (DNS issue)
2. High connection setup time (indicates load balancer issues)
3. High Request send time (indicates n/w or firewall throttling issues)
4. High request receive time (same as #3)
Now, the time that you see in Apache logs are mostly visible to JMeter as time to first byte time. I am not sure about the machine that you are running your testing. If your worker can support curl, use Curl to find the components for a single request.
echo 'request payload for POST'
| curl -X POST -H 'User-Agent: myBrowser' -H 'Content-Type: application/json' -d #- -s -w '\nDNS time:\t%{time_namelookup}\nTCP Connect time:\t%{time_connect}\nAppCon Protocol time:\t%{time_appconnect}\nRedirect time:\t%{time_redirect}\nPreXfer time:\t%{time_pretransfer}\nStartXfer time:\t%{time_starttransfer}\n\nTotal time:\t%{time_total}\n' http://mytest.test.com
If the above output indicates no such issues then the time must have been spent within JMeter. You should tune your JMeter implementation by using various options like beanshell / JSR223 etc.

Related

JMeter , Execution order is not correct

I have 4 transaction controllers named
Trans_api1
__Http Request
Trans_api2
__Http Request
Trans_api3
__Http Request
Trans_api4
__Http Request
that contain Http Requests, However when I run my test plan, I want them to run in numerical order but then they run randomly. How do I fix the order to it runs from 1-4?
Each JMeter thread (virtual user) runs Samplers upside down so you don't need to do anything, your requests are executed from top to bottom already. If you run your test with 1 user - you will see that requests are being executed sequentially.
If you're seeing some "mess" most probably it's caused by concurrency, like
1st user starts 1st request
2st user starts 2nd request
2nd user starts 1st request
1st user starts 3rd request
etc.
You can see this yourself if you add ${__threadNum} function as the prefix or postfix for your request (or transaction controller) label and eventually ${__groovy(vars.getIteration(),)} function to display the current loop number
With 1 user:
With 2 users:
With 2 users and 2 iterations:
As it evidenced by the above images each users executes samplers sequentially on each iteration, these "inconsistencies" are misleadingly interpreted due to concurrency
See Apache JMeter Functions - An Introduction article to get familiarized with JMeter Functions concept

Catchpoint pause vs. waitForNoRequest - What's the difference?

I have a test that was alerting because it was taking extra time for an asset to load. We changed from waitForNoRequest to a pause (at Catchpoint's suggestion). That did not seem to have the expected effect of waiting for things to load. We increased the pause from 3000 to 12000 and that helped to allow the page to load and stop the alert. We noticed some more alerts, so I tried to increase the pause to something like 45000 and it would not allow me to pause for that long.
So the main question here is - what functionality does both of these different features provide? What do I gain by pausing instead of waiting, if anything?
Here's the test, data changed to protect company specific info. Step 3 is where we had some failures and we switched between pause and wait.
// Step - 1
open("https://website.com/")
waitForNoRequest("2000")
click("//*[#id=\"userid\"]")
type("//*[#id=\"userid\"]", "${username}")
setStepName("Step1-Login-")
// Step - 2
clickMouseAndWait("//*[#id=\"continue\"]")
waitForVisible("//*[#id=\"challenge-password\"]")
click("//*[#id=\"challenge-password\"]")
type("//*[#id=\"challenge-password\"]", "${password}")
setStepName("Step2-Login-creds")
// Step - 3
clickMouseAndWait("//*[#id=\"signIn\"]")
setStepName("Step3-dashboard")
waitForTitle("Dashboard")
waitForNoRequest("3000")
click("//*[#id=\"account-header-wrapper\"]")
waitForVisible("//*[#id=\"logout-link\"]")
click("//*[#id=\"logout-link\"]")
// Step - 4
clickAndWait("//*[text()=\"Sign Out\"]")
waitForTitle("Login - ")
verifyTextPresent("You have been logged out.")
setStepName("Step5-Logout")
Rachana here, I’m a member of the Technical Service Team here at Catchpoint, I’ll be happy to answer your questions.
Please find the differences below between waitForNoRequest and Pause commands:
Pause
Purpose: This command pauses the script execution for a specified amount of time, whether there are HTTP/s requests downloading or not. Time value is provided in milliseconds, it can range between 100 to 30,000 ms.
Explanation: This command is used when the agent needs to wait for a set amount of time and this is not impacted by the way the requests are loaded before proceeding to the next step or command. Only a parameter is required for this action.
WaitForNoRequest
Purpose: This commands waits for a specified amount of time, when there was no HTTP/s requests downloading. The wait time parameter can range between 1,000 to 5,000 ms.
Explanation: The only parameter for this action is a wait time. The agent will wait for that specified amount of time before moving onto the next step/command. Which will, in return, allow necessary requests more time to load after document complete.
For instance when you add waitforNoRequest(5000), initially agent waits 5000 ms after doc complete for any network activity. During that period if there is any network activity, then the agent waits another 5000 ms for the next network activity to end and the process goes on until no other request loads within the specified timeframe(5000 ms).
A pause command with 12000 ms, gives exactly 12 seconds to load the page. After 12 seconds the script execution will continue to next command no matter the page is loaded or not.
Since waitForNoRequest has a max time value of 5000 ms, you can tell the agent to wait for a gap of 5 seconds when there is no network activity. In this case, the page did not have any network activity for 3 seconds and hence proceeded to the next action. The page was not loaded completely and the script failed.
I tried to increase the pause to something like 45000 and it would not allow me to pause for that long.
We allow a maximum of 30 seconds pause time hence 45 seconds will not work.
Please reach out to our support team and we’ll be glad to connect you with our scripting SMEs and help you with any scripting needs you might have.

concurrent testing of login functionality with 50 users/threads is not working

i have given the thread count = 50
rampup period =0
for 48 threaads it is getting passed , for 2 threads there is no failure captured in the selenium log files.
I am expecting concurrent login of 50 users with 0 rampup period , i am not able to find out the exact reason of failure . please suggest the fixes to handle this scenario.
Check jmeter.log file for any suspicious entries
Add View Results Tree listener to your test plan - it will allow you to inspect request and response details
50 real browsers might be too high for a single machin
as per WebDriver Sampler documentation
From experience, the number of browser (threads) that the reader creates should be limited by the following formula:
C = N + 1
where
C = Number of Cores of the host running the test
and N = Number of Browser (threads).
as per Firefox 62.0 system requirements
512MB of RAM / 2GB of RAM for the 64-bit version
So you will need a machine with 51 cores and 100 GB of RAM in order to ensure there will no be JMeter-side bottleneck. If your machine hardware specifications are lower - you will have to go for Remote Testing

ServerXmlHttpRequest hanging sometimes when doing a POST

I have a job that periodically does some work involving ServerXmlHttpRquest to perform an HTTP POST. The job runs every 60 seconds.
And normally it runs without issue. But there's about a 1 in 50,000 chance (every two or three months) that it will hang:
IXMLHttpRequest http = new ServerXmlHttpRequest();
http.open("POST", deleteUrl, false, "", "");
http.send(stuffToDelete); <---hang
When it hangs, not even the Task Scheduler (with the option enabled to kill the job if it takes longer than 3 minutes to run) can end the task. I have to connect to the remote customer's network, get on the server, and use Task Manager to kill the process.
And then its good for another month or three.
Eventually i started using Task Manager to create a process dump,
so i could analyze where the hang is. After five crash dumps (over the last 11 months or so) i get a consistent picture:
ntdll.dll!_NtWaitForMultipleObjects#20()
KERNELBASE.dll!_WaitForMultipleObjectsEx#20()
user32.dll!MsgWaitForMultipleObjectsEx()
user32.dll!_MsgWaitForMultipleObjects#20()
urlmon.dll!CTransaction::CompleteOperation(int fNested) Line 2496
urlmon.dll!CTransaction::StartEx(IUri * pIUri, IInternetProtocolSink * pOInetProtSink, IInternetBindInfo * pOInetBindInfo, unsigned long grfOptions, unsigned long dwReserved) Line 4453 C++
urlmon.dll!CTransaction::Start(const wchar_t * pwzURL, IInternetProtocolSink * pOInetProtSink, IInternetBindInfo * pOInetBindInfo, unsigned long grfOptions, unsigned long dwReserved) Line 4515 C++
msxml3.dll!URLMONRequest::send()
msxml3.dll!XMLHttp::send()
Contoso.exe!FrobImporter.TFrobImporter.DeleteFrobs Line 971
Contoso.exe!FrobImporter.TFrobImporter.ImportCore Line 1583
Contoso.exe!FrobImporter.TFrobImporter.RunImport Line 1070
Contoso.exe!CommandLineProcessor.TCommandLineProcessor.HandleFrobImport Line 433
Contoso.exe!CommandLineProcessor.TCommandLineProcessor.CoreExecute Line 71
Contoso.exe!CommandLineProcessor.TCommandLineProcessor.Execute Line 84
Contoso.exe!Contoso.Contoso Line 167
kernel32.dll!#BaseThreadInitThunk#12()
ntdll.dll!__RtlUserThreadStart()
ntdll.dll!__RtlUserThreadStart#8()
So i do a ServerXmlHttpRequest.send, and it never returns. It will sit there for days (causing the system to miss financial transactions, until come Sunday night i get a call that it's broken).
It is of no help unless someone knows how to debug code, but the registers in the stalled thread at the time of the dump are:
EAX 00000030
EBX 00000000
ECX 00000000
EDX 00000000
ESI 002CAC08
EDI 00000001
EIP 732A08A7
ESP 0018F684
EBP 0018F6C8
EFL 00000000
Windows Server 2012 R2
Microsoft IIS/8.5
Default timeouts of ServerXmlHttpRequest
You can use serverXmlHttpRequest.setTimeouts(...) to configure the four classes of timeouts:
resolveTimeout: The value is applied to mapping host names (such as "www.microsoft.com") to IP addresses; the default value is infinite, meaning no timeout.
connectTimeout: A long integer. The value is applied to establishing a communication socket with the target server, with a default timeout value of 60 seconds.
sendTimeout: The value applies to sending an individual packet of request data (if any) on the communication socket to the target server. A large request sent to a server will normally be broken up into multiple packets; the send timeout applies to sending each packet individually. The default value is 30 seconds.
receiveTimeout: The value applies to receiving a packet of response data from the target server. Large responses will be broken up into multiple packets; the receive timeout applies to fetching each packet of data off the socket. The default value is 30 seconds.
The KB305053 (a server that decides to keep the connection open will cause serverXmlHttpRequest to wait for the connection to close) seems like it plausibly could be the issue. But the 30 second default timeout would have taken care of that.
Possible workaround - Add myself to a Job
The Windows Task Scheduler is unable to terminate the task; even though the option is enabled to do do.
I will look into using the Windows Job API to add my self process to a job, and use SetInformationJobObject to set a time limit on my process:
CreateJobObject
AssignProcessToJobObject
SetInformationJobObject
to limit my process to three minutes of execution time:
PerProcessUserTimeLimit
If LimitFlags specifies
JOB_OBJECT_LIMIT_PROCESS_TIME, this member is the per-process
user-mode execution time limit, in 100-nanosecond ticks. Otherwise,
this member is ignored.
The system periodically checks to determine
whether each process associated with the job has accumulated more
user-mode time than the set limit. If it has, the process is
terminated.
If the job is nested, the effective limit is the most
restrictive limit in the job chain.
Although since Task Scheduler uses Job objects to also limit a task's time, i'm not hopeful that the Job Object can limit a job either.
Edit: Job objects cannot limit a process by process time - only user time. And with a process idle waiting for an object, it will not accumulate any user time - certainly not three minutes worth.
Bonus Reading
How can a ServerXMLHTTP GET request hang? (GET, not POST)
KB305053: ServerXMLHTTP Stops Responding When You Send a POST Request (which says the timeout should expire; where mine does not)
MS Forums: oHttp.Send - Hangs (HEAD, not POST)
MS Forums: ASP to test SOAP WebService using MSXML2.ServerXMLHTTP Send hangs
CC to MS Support Forums
Consider switching to a newer, supported API.
msxml6.dll using MSXML2.ServerXMLHTTP.6.0
winhttpcom.dll using WinHttp.WinHttpRequest.5.1.
The msxml3.dll library is no longer supported and is only kept around for compatibility reasons. Plus, there were a number of security and stability improvements included with msxml4.dll (and newer) that you are missing out on.

JMeter HTTP Request Post Body from File

I am trying to send an HTTP request via JMeter. I have created a thread group with a loop count of 25. I have a ramp up period of 120 and number of threads set to 30. Within the thread group, I have 20 HTTP Requests. I am a little confused as to how JMeter runs these requests. Do each of the 20 requests within a thread group run in a single thread, and each loop over a thread group runs concurrently on a different thread? Or do each of the 20 requests run in different threads as and when they are available.
My other question is, Over each loop, I want to vary the body of the post data that is being sent via the HTTP request. Is it possible to pass the post data body via a file instead of inserting the data into the JMeter Body Data Tab as show below:
However, instead of doing that, I want to define some kind of variable that picks a file based on iteration of the threadgroup that is running, for example, if it is looping over the thread group the second time, i want to call test2.txt, if the third time test3.txt etc and these text files will contain different post data. Could anyone tell me if this is possible with JMeter please and if so, how would I go about doing this.
Point 1 - JMeter concurrency
JMeter starts with 1 thread and spawns more threads as per ramp-up set. In your case (30 threads and 120 seconds ramp-up) another thread is being added each 4 seconds. Each thread executes 20 requests and if there is another loop - starts over, if there is no loop - the threads shuts down. To control load and concurrency JMeter provides 2 options:
Synchronizing Timer - pause all threads till specified threshold is reached and then release all of them at the same time
Constant Throughput Timer - to specify the load in requests per minute.
Point 2 - Send file instead of text
You can replace your request body with __fileToString function. If you want to parametrize it you can use nested function to provide current iteration - see below.
Point 3 - adding iteration as a parameter
JMeter provides 2 options on how you can increment a counter each loop
Counter config element - starts from specified value and gets incremented by specified value each time it's called.
__counter function - start from 1 and gets incremented by 1 each time it's being called. Can be "per-user" or "global"
See How to Use JMeter Functions post series for comprehensive information on above and more JMeter functions.