Thank you for your post.
I cannot explain the difference, so I have sent your post and file to our Development and Testing departments for an explanation. When I receive any feedback, I will let you know.
This meets a theory by HOnzaKoudelka back in 2012:
Comparative operators in #FileMaker relationships are speed killers
I experience much better performance since I avoid comparative (< ≤ > ≥) AND carthasian ( x ) operators.
You can use Custom Functions to avoid comparative operators:
I also use a formula field "rel_1" = 1 [indexed] in every table to avoid "X" Relations.
The Relationship filter is evaluating query for every record. A portal filter executes one query for the first record and then uses cached data for other records. In essence, one query versus several (in your case, thousands) queries.
Thank you, I also use 1 = 1 for all but I do not think there was much difference
with the Relationship filter / Portal filters
this allows to further optimize, I used max cached now
Thank you very much for your responses / confirmations and links