Information regarding Table-Locks

Hi,

I have a few doubts regarding table locks. Assume I am executing the
following query

Query 1 -- INSERT INTO FOREIGN_TABLE SELECT * FROM POSTGRES_TABLE

Query 2 -- INSERT INTO FOREIGN_TABLE SELECT * FROM FOREIGN_TABLE

If i get a table lock for the foreign table , will the second table from
which i am getting the data will also come under this lock ?? Or is it a
separate lock ?? Does postgres handle that lock ??

What kind of lock will the second table will be in ?? Can i rename the
second table while executing the INSERT QUERY ??

Thanks,
Harsha