anchor.diff:  
       {DataSize, FileSize} =
           lists:foldl(
  -          fun (DbName, {AccDataSize, AccFileSize}) ->
  +          fun ({_VBucket, DbName}, {AccDataSize, AccFileSize}) ->
                     {ok, Db} = couch_db:open_int(DbName, []),
   
                     %% unfortunately I can't just bind this inside try block
  
positive.code:            [{vbuckets_done, Ix},
              {progress, Progress}]).
  
  spawn_vbucket_compactor(DbName) ->
      Parent = self(),
  
      proc_lib:spawn_link(
        fun () ->
                {ok, Db} = couch_db:open_int(DbName, []),
  
                %% effectful
                ensure_can_db_compact(Db),
  
negative.code: all_bucket_dbs(BucketName) ->
      BucketConfig = get_bucket(BucketName),
      NodeVBuckets = ns_bucket:all_node_vbuckets(BucketConfig),
      VBucketDbs = [{V, db_name(BucketName, V)} || V <- NodeVBuckets],
  
      [{master, db_name(BucketName, "master")} | VBucketDbs].
  
  get_bucket(BucketName) ->
      get_bucket(BucketName, ns_config:get()).
  