Loop Nodes Problem "ArrayIndexOutOfBoundsException"


this time I'm facing a rather general problem. I searched the Forum as well as the web, but wasn't able to find anything similar, which would help in my situation.

I'm using KNIME 3.0.1 (having the same issue on both, Windows and Linux 64bit Versions).

My workflow is as follows:

Reading in Wiki Random Article URL - Counting Loop Start -do some crazy Extraction/Join/Filter/Manipulation stuff - Loop End - Table writer.

I set the "Number of Loops" at the "Counting Loop Start" Node's Configuration to 1000.

The error thrown at the "Loop End" Node is

ERROR Loop End             2:29       Execute failed: ("ArrayIndexOutOfBoundsException"): 8

I already increased the heap to 4gig (as mentioned quite often as a solution for such issues).

Also, I tried all the Memory Policy posibilities available in the different Node's configuartions. Currently set to "write tables to disc" (as I suppose it's the best way to go in case of lack of memory or the like).

Quite interessting is the fact that sometimes it loops only less than 10 times. Sometimes more than 500 times and so on - quite random (which makes me think it isn't due to memory limits or or other hardware related facts).

I'm runnning KNIME on a Quadcore i5-2410M CPU @ 2.3GHz Processor machine with 6gig of RAM.

I'm thankful for any help, suggestion or idea!


Hi Manu,

thanks for reporting the problem. Could you please attach a minimal example workflow where the problem occurs?




Hi Martin,


thanks for your reply. Sry it took me a while, but I was able to run the Flow on another machine with an i7 8core in the meantime. Of course, now it works just fine, so I'm strongly assuming my i5 machine was just too weak (what I find quite weird). If you still want to have a look at the flow, I attached it to the post.

I'm still welcoming any discussion about that.