If I run the request that times out with explain=details, I do not get any useful explanations at all, even though pre-query output should be available. Ideally, the pre-query output should be sent out before the query is done, and be available even if query times out.

Also, it would be nice to be able to have explain mode that does not run the execute stage of the query at all, when we're only interested in the optimizer parts.