KNIME freezes when "Start WebDriver" is failed and re-executed several times


When “Start WebDrive” fails for whatever reason (e.g. when I force close the browser while the node is executing) and it’s re-executed, the last WebDriver won’t be ended and a new WebDriver is started so if the process is done several times then the Task Manager (in Windows) under KNIME shows multiple WebDriver and I think that’s why my KNIME freezes when I’m working with the nodes and re-execute the “Start WebDriver” several times.


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Hi Armin,

first, may I ask why you need to force-close the browser window? From my feeling, this should not be necessary in normal usage scenarios.

Keeping track of leftover processes which happen when a browser is being force-quit is quite hard and error-prone through the Selenium API, so we currently do not take any measures to do this.

What driver/browser are you using? And to clarify, the left-over processes are “chromedriver” resp. “chromedriver.exe”? And to clarify, can you describe why the node execution fails in first place?


I did that to reproduce the problem.
I’m not sure what exactly I did (except that I was working with Selenium nodes and was re-executing the nodes again and again) that KNIME got frozen (all the panels blacked) (and I hadn’t experience this in KNIME 3.6.x - I’m not sure if the version has anything to do with this) but when I checked the task manager I saw the unclosed “chromedriver.exe” tasks (and Console Window Host) under KNIME.
I will consider not to close the browser manually from now on. (Still not quite sure if I was doing that when KNIME got frozen)
I just wanted to ask about the behavior. So if it’s because of the force closing the browser here I know not to do that again. :blush::wink:


PS: Even if there are several chromedriver processes unclosed (in my case they were about 5), is it expected for KNIME to be frozen? On my system KNIME is using 12 GB of RAM and when it was frozen system had lots of free RAM yet and was working properly.

Thanks for the feedback – I’ve noted it and we’ll investigate whether we can improve the “housekeeping” regarding left over processes.

Regarding the issue of KNIME becoming unresponsive: This should (obivously :slight_smile: ) not be the case, but I have some assumption about the reason, which I would like to double-check. Would you be able and willing to share your knime.log file? (you can send it via email to me in case your prefer to keep it private)


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It’s OK with me to share the log file but I checked the file and there is no entry related to the problem at the time this problem occurred. (There is just one entry for the time and I can remember the error- it didn’t make any problem)
However this is the log file:
.bak_0.log (1004.3 KB)

The problem occurred about 11~12 AM 2019-02-19 (this problem had occurred a few times in the past but I cannot remember the time).



This is very nice of you. Here in Iran we are close to our new year and all the people are doing a full “housekeeping” (which is a tradition here). So if you do so then you can celebrate our new year as well. :wink:

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