[Postgres-xc-general] Data Node Scan Performance

[Aaron J. <aja...@re...>]

I have a table that I've distributed by some key K.  When I want to query by some other dimension Q, the coordinator explain plan indicates that it does a Data Node Scan on *table* "_REMOTE_TABLE_QUERY"

Now what I've noticed is that if I have 4 nodes, the coordinator based scan may take 65 seconds, however, the individual date nodes usually finish within 5-10 seconds.  The individual explain plains from each data node reveal nothing.  So my question is, does the coordinator execute the data node scan serially or in parallel - and if it's serially, is there any thought around how to make it parallel?

In the event it is already parallel, is the time differential I'm seeing simply attributed to the coordinator gathering results in preparation to return to the requesting client?

Thanks