questions about very large table and partitioning

Hi all,

I'm trying to create a very large table with more than 0.6 billion rows,
which is really a big number, so I think I have to create partitioned
tables after some googling.

However, I have a few questions about partitioning in PostgreSQL.

1) PostgreSQL only support partition by inheritance, and rules have to
be created for each child table, this will result *a lot of* rules if
the number of child tables is large.

Are there some smart ways to avoid this kind of mass ?

2) I have added check constraints for child tables. According to the
documents, "query performance can be improved dramatically for certain
kinds of queries". Does this mean that the query can be improved only if
the query contains the constrained column? What will happen if the
constrained column doesn't appear in the WHERE clause?

3) Is partition by inheritance the only appropriate way to organize very
large table in PostgreSQL ?

Thanks in advance.