A few academic questions related PostgreSQL query planner and output -
In the output of EXPLAIN for SQL statements I have seen so far, the startup cost for the innermost node/leaf has been 0. Are there situations where it may be non-zero?
The startup costs for outer nodes will always be equal to or greater than the total cost of the inner nodes? (My guess is NO, there may be cases where the outer node can start processing before the inner node is completely done).