Fix unstable test in select_parallel.sql
One test case added in
22d946b0f verifies the plan of a non-parallel
nestloop join. The planner's choice of join order is arbitrary, and
slight variations in underlying statistics could result in a different
displayed plan. To stabilize the test result, here we enforce the
join order using a lateral join.
While here, modify the test case to verify that parallel nestloop join
is not generated if the inner path is not parallel-safe, which is what
we wanted to test in
22d946b0f.
Reported-by: Alexander Lakhin as per buildfarm
Author: Richard Guo
Discussion: https://postgr.es/m/
7c09a439-e48d-5460-cfa0-
a371b1a57066@gmail.com