Is there a limitation on the number of inputs for Join tool?

[mariiaa]

I work with a workflow that joins lots of inputs, and recently I started to receive this message on limitation on the number of inputs up to 32 (see attached). Sometimes I don't receive it. I am curious how this problem is fixed? Should I switch on smth somewhere manually to get rid of this limitation? 

[binuacs]

@mariiaa I think there is a limitation in the Union tool for the incoming connections. If you have more than 32 connections then use a batch macro to solve the issue or use multiple union tools

[Luke_C]

Hi @mariiaa 

I agree with @binuacs. if these inputs all have the same schema (layout) it would be better to use a batch macro or a single input with a wildcard to read everything in. There are tons of examples of both on the community. If you give some more information on your fact pattern we could see what the best option would be.

[mariiaa]

haven't heard of batch macros, will definitely look it up. the problem is that i haven't found evidence of the existence of such limitations for join tool, and in my case it sometimes works and sometimes shows error message. i want to know what the rule is here 

[GTilbury · Accepted solution]

Hi.  I also experienced this issue today on an old workflow where I was processing a significant number of files that were not the same schema.  Alteryx is used to adjust each file to a new standard dynamically before applying the union query.  In previous versions of Alteryx this worked, but not in the newer release.  I suspected this might be a difference on the new AMP engine and so turned off the AMP engine and re-ran.  This solved the issue and I no longer have the Error "Union (64): The number of incoming connections has exceeded the maximum. Please adjust the number so that there are 32 or fewer".  I could change the default to not use the AMP engine in the runtime tab of the workflow configuration (see Alteryx AMP Engine | Alteryx Help)