WU Yan <4wuyan@xxxxxxxxx> writes: > Hello everyone, I am still learning postgres planner and performance > optimization, so please kindly point out if I missed something obvious. An index on employee.name would likely help here. Even if we had an optimization for pushing LIMIT down through a join (which you are right, we don't) it could not push the LIMIT through a sort step. So you need presorted output from the scan of "employee". I think this example would behave better with that. You may also need to test with non-toy amounts of data to get the plan you think is better: an example with only half a dozen rows is going to be swamped by startup costs. regards, tom lane
