So you distribute the childtables to several nodes of a server cluster.
Is network latency a problem? I guess one should colocate the servers in one location rather than spread it out?
How good does it work when nodes die?
Do you use query parallelization (available since 9.6 in vanilla) on a single node and across different nodes?
Query parallelization works in single and multi-node cases.
This is also true at write time: You can insert a batch of rows in a single insert, then the query planner will split them into sub-batches, which it then will insert into the appropriate chunk. So, you don't need to "pre-partition" your data before writing to the system (even in the forthcoming distributed version).