Are buckets persistent?

David,

This is a continuation of the thought started here.

On our earlier conversations here, I had the impression that buckets had a persistence aspect. From reviewing the docs, and your comments on this thread, it appears I am mistaken. It appears that routing + shards is the the only path for me.

I suppose the next question becomes: When I do bucket aggregations, how do I make sure the ES limits itself to a single shard? (Does routing apply to bucket aggregations?)

Thank you!