Since SUREFIRE-938 the output of test is buffered in /tmp/stdout*deferred in order to create XML report. I am not interested in the report in XML or any other form, but I gather gigabytes of logs during the test executions, and write them to /tmp, too. Sometimes the total size of both buffer file and the output log is too big and it won't fit - is there a way to disable the report and all this buffering (which slows down the test as well)?
Related
I am part of tractor pulling team and we have Bechoff CX8190 based PLC for data logging. System works most of the time but every now and then saving sensor values (every 10ms is collected) to CSV fails (mostly in middle of csv row). Guy who build the code is new with the TwinCAT and does not know how to find what causes that. Any Ideas where to look reason for this.
Writing to a file is always a asynchron action in TwinCAT. That is to say this is no realtime action and it is not safe that the writing process is done within the task cycletime of 10ms. Therefore these functionblocks always have a BUSY-output which has to be evaluated and the functionblock has to be called successivly until the BUSY-output returns to FALSE. Only then a new write command can be executed.
I normally tackle this task with a two-side-buffer algorithm. Lets say the buffer-array has 2x100 entries. So fill up the first 100 entries with sample values. Then write them all together with one command to the file. When its done, clean the buffer. In the meanwhile the other half of the buffer can be filled with sample values. If second side is full, write them all together to the file ... and so on. So you have more time for the filesystem access (in the example above 100x10ms=1s) as the 10ms task cycletime.
But this is just a suggestion out of my experience. I agree with the others, some code could really help.
Apache Jmeter has the -l option for logging the results. However, it creates a single file. If the test is run for quite some time, this log file becomes huge and it takes time to process this file. Is there a way where we can rotate the log file based on file size?
As of current JMeter version 5.2.1 it is not possible, the options are in:
Use i.e. split program to break up large .jtl file into smaller pieces. More information:
How to Split Large Text File into Smaller Files in Linux
Don't use .jtl results file and switch to Backend Listener so the results would go to external database and you can interactively choose smaller chunks, perform filtering, etc. More information:
Real-time results
How to Use Grafana to Monitor JMeter Non-GUI Results
I am running a stability test (60hrs) in Jmeter. I have several graphs in the test plan to capture system resources like cpu, threads, heap.
The size of View_Results_Tree.xml file is 9GB after 24hrs. I am afraid if jmeter will sustain for 60hrs.
Is there size limit for View_Results_Tree.xml or results folder size in Jmeter?
What are the best practices to be followed in Jmeter before running such long tests? I am looking for recommended config/properties for such long tests.
Thanks
Veera.
There is no results file limit as long as it fits into your hard drive for storing or in your RAM to open and analyze.
The general recommendations are:
Use CSV format instead of XML
Store only those metrics which you need to store, saving unnecessary stuff causes massive memory and disk IO overheads.
If you look into jmeter.properties file (located in JMeter's "bin" folder) for properties which names start with jmeter.save.saveservice i.e.
#jmeter.save.saveservice.output_format=csv
#jmeter.save.saveservice.assertion_results_failure_message=true
#etc.
Copy them all to user.properties file, set "interesting" properties to true and others to false - that will allow to save a lot of disk space and release valuable resources for the load testing itself.
See 9 Easy Solutions for a JMeter Load Test “Out of Memory” Failure for more detailed explanation of the above recommendations and few more JMeter performance tuning tweaks.
There are not limits on file size in JMeter, the limit is your your disk space.
From the file name, I guess you chose XML output, it is better to choose CSV output (see below another reason for that).
Besides, ensure you're not using GUI for load testing in JMeter which is a bad practice, this will certainly break your test if you do it.
Switch to Non GUI mode and ensure you follow those recommendations.
/bin/jmeter -t -n -l /results.csv
Since JMeter 3.0, you can even generate report at end of load test of from an existing CSV (JTL, not from XML format) file, see:
http://jmeter.apache.org/usermanual/generating-dashboard.html
As you need GUI for monitoring, run Jmeter in GUI mode only for the monitoring part.
I agree with the answer provided by UBIK LOAD PACK. But in case if you need to have the results stored somewhere you don't need to worry about the size of the file. The best solution is using Grafana and Graphite (InfluxDB) for realtime reports and efficient storage.
I am running jmeter through the command line, and generating a jtl log file. The last couple of runs, it seems that it has created a couple of different .jtl files, with one of them starting in the middle of the run. Is there a Maximum Length of a Log File, or has anyone seen anything like this before?
Thanks
The JTL files can grow as large as they need to be. In some cases my tests yield JTL files over 25 gigs in size.
However, if you do not change the JTL name between runs it will append to the file, not overwrite. Is it possible you are looking at two test runs in a single JTL file? You would see a big chunk where it looks like there are no results.
If you are running from command line, my suggestion would be to build a shell or batch script that auto timestamps the jtl parameter and starts the test. This way you are guaranteed, without any thinking, to have new files for each run.
Also, just so you are aware: There is a nice plugin jar that will allow you to generate awesome graphs from a raw JTL file!
http://jmeter-plugins.org/wiki/JMeterPluginsCMD/
I am running a Hadoop mapreduce streaming job (mappers only job). In some cases my job writes to stdout whereupon an output file with non-zero size is created. In some cases my job does not write anything to stdout but still an output file of size zero is created. Is there a way to avoid creation of this file of size zero when nothing is written to stdout.
If you don't mind extending your current output format, you just need to override the OutputCommitter to 'abort' the commitTask stage when no data was written.
Note that not all output formats show zero file bytes for an empty file (sequence files for example have a header), so you can't just check the output file size.
Look at the source for the following files:
OutputCommitter - The base abstract class
FileOutputCommitter - Most FileOutputFormats use this committer so it's a good place to start. Look into the private method moveTaskOutputs, this is where your logic will most likely go (to not copy the file if nothing was written)
Are you using MultipleOutputs?
If yes, MultipleOutputs creates defaults files even if the reducer has nothing to write to the output.
To avoid this default zero-sized output, you can use LazyOutputFormat.setOutputFormatClass()
From my experience, even if you are using LazyOutputFormat, zero-sized files are created when: Reducer has some data to write (so output file is created) but reducer gets killed before writing the output. I believe this is a timing issue, so you might observe that only partial reducer output files are present in HDFS or you may not observe this at all.
eg. If you have 10 reducers, you might have only 'n' (n<=10) number of files and some of them have file size equal to 0 bytes.