I have a flow with many nodes that depend on the data from that first HTTP Request. However, for some reason I cannot pass it to the last Amazon Comprehend node. The previous three work just fine (all with data from that HTTP call) but the last one I keep getting the error: Problem in node ‘AWS Comprehend_Bullets0‘
Can’t get data for expression
And the variables are red -
Is there a limit on how many nodes can access data from the same API call? I tried to use a function to aggregate the data so I could save it to a variable and do it that way but the data was inaccessible there too. I also moved the node closer to that API call…it ONLY works if it is the NEXT node right after that HTTP request. BUT, then further nodes stop having access to the same variables. So it appears there is a limit to how far the data can travel?
I’m hoping to avoid doing this in multiple workflows so that I don’t have to use up too many API calls.
Any advice?
I decided to try and just split this up into two workflows, but now, even with less nodes, the last node cannot access the second node’s data. I don’t understand what is happening or how to fix it but this is extraordinarily frustrating.
You can use the merge node to combine data from multiple paths. As you obly got one item, you can merge “by position”
@giulioandreini I do not know where the problem is here, but thats one of the issues i had previously. (Regarding my question from the last community stream)
There’s no limit on how many nodes can access data, and there’s no limit on how far in your workflow you can access data.
The error could be caused by some item linking issue (item linking is how n8n can go up the chain of nodes and connect the various items Item linking concepts | n8n Docs)
Just to be sure I understand the problem, is this the case?
Yes, this was the problem. It manifested the same way in a couple of different instances though. All with the same bundles. The problem wasn’t with the items coming from these Comprehend nodes, but from the very first HTTP node. Item count for that API call was around 6 (for that one parameter). This API call had a LOT of data though (6 items for “features”, 1 item for “title”, 20+ items for “reviews”, etc)
Thanks for the details @Anthony_Lee
We identified the issue and it is related to how the AWS Comprehend handles items linking.
The fix is already in our pipeline and we’ll post a message here when fixed
I’d also like to note that I am successfully passing this same data in other nodes, but it seems after a Merge node or if the node is “too far back” the data becomes unavailable.
