Re: [HACKERS] Block level parallel vacuum

Few other things, I would like you to consider.

1.  I think disable_parallel_leader_participation related code can be extracted into a separate patch as it is mainly a debug/test aid.  You can also fix the problem reported by Mahendra in that context.

2. I think if we cam somehow disallow very small indexes to use parallel workers, then it will be better.   Can we use  min_parallel_index_scan_size to decide whether a particular index can participate in a parallel vacuum?