do messages be queryable immediately by using tranquility as realtime ingestion?

HI, there:

From the druid doc, I know messages passing to realtime node can be queried immediately. But using tranquility the messages are passed to index service which seams not be queryable.

     I wonder if I use tranquility as my realtime ingestion, when messages are ingesting to the index service, can I query on those messages which haven’t been built into segments?

Yes, as soon the druid realtime node gets the data, it will be available to query.

I knew the realtime node can do this.
what I am confused is that using tranquility messages are passed to index service, that is overlord node, not realtime node, does overlord or middle manager have query ability? as far as l know the druid doc doean’t say that.

I can follow up with a longer explanation, but please first read this thread:
https://groups.google.com/forum/#!searchin/druid-development/fangjin$20yang$20%22thoughts%22/druid-development/aRMmNHQGdhI/muBGl0Xi_wgJ