docs: Chasm and fan traps

Author: paveltiunov

docs/pages/reference/data-model/joins.mdx

@@ -409,6 +409,9 @@ cubes:
 Cube automatically detects chasm and fan traps based on the `many_to_one` and `one_to_many` relationships defined in join.
 When detected, Cube generates a deduplication query that evaluates all distinct primary keys within the multiplied measure's cube and then joins distinct primary keys to this cube on itself to calculate the aggregation result.
 If there's more than one multiplied measure in a query, then such query is generated for every such multiplied measure, and results are joined.
+Cube solves for chasm and fan traps during query time.
+If there's pre-aggregregation that fits measure multiplication requirements it'd be leveraged to serve such a query.
+Such pre-aggregations and queries are always considered non-additive for the purpose of pre-aggregation matching.
 
 Let's consider an example data model: