In the segmented case, distributed builds move from "a single index written in a distributed fashion, then a final merge" to "creating multiple independent segments in a distributed fashion" — each worker produces one canonical segment（At query time the segments of one logical index are unioned automatically.）
Manual UUIDs are no longer supported because each worker must produce a distinct physical segment with its own UUID; user-specified UUIDs can collide across workers and corrupt or overwrite segment outputs.
In general, under the framework of segmented index, users should be prohibited from manually specifying the index UUID regardless of whether the index is created in a distributed or standalone manner.
In the segmented case, distributed builds move from "a single index written in a distributed fashion, then a final merge" to "creating multiple independent segments in a distributed fashion" — each worker produces one canonical segment（At query time the segments of one logical index are unioned automatically.）
Manual UUIDs are no longer supported because each worker must produce a distinct physical segment with its own UUID; user-specified UUIDs can collide across workers and corrupt or overwrite segment outputs.
In general, under the framework of segmented index, users should be prohibited from manually specifying the index UUID regardless of whether the index is created in a distributed or standalone manner.