I have a filter that checks if at least one message exists for a given thread:
<$list filter="[field:thread_id{!!thread_id}tag[message]first[]]" variable=none>
This works but it is slow. I think it is caused by the fact that firstly a list of all messages is created which finally will be mostly thrown away via the first[] operator. (Since the number of messages it sometimes high and it is iterated over all threads it takes some time.)
So my question is: Can I check for some tiddler without creating the list first?
So I activated the Performance Instrumentation in TiddlyWiki and received these numbers. My notebook has an i7-10750H.