[Docs] Update aggregations.asciidoc
Add note about accuracy of some aggregation results.
@@ -40,6 +40,10 @@ NOTE: Bucketing aggregations can have sub-aggregations (bucketing or metric). Th
aggregations (one can nest an aggregation under a "parent" aggregation, which is itself a sub-aggregation of
another higher-level aggregation).
+NOTE: Aggregations operate on the `double` representation of
+ the data. As a consequence, the result may be approximate when running on longs
+ whose absolute value is greater than `2^53`.
+
[float]
== Structuring Aggregations
