I am trying to measure startup time of postmaster. Say I have postmaster running on -D /tmp/d1 and would like to restart it on -D /tmp/d2.
If I just say time pg_ctl restart -D /tmp/d2 it will not produce an accurate result because pg_ctl will start postmaster in the background and return immediately but if you query the engine right away, you'll see that it is not ready yet as in time ( pg_ctl restart -D /tmp/d2 ; psql -l )
If I call postmaster, then the command is blocking waiting for postmaster to exit. I am sure there is a way...but I figured I ask my good friends first...