That's good to rule out db differences, but that doesn't explain where in transit the 15 ms difference is between HTTP and WS for established connections. I'm

That's good to rule out db differences, but that doesn't explain where in transit the 15 ms difference is between HTTP and WS for established connections. I'm assuming the most likely difference is in Pg processing an HTTP request over processing raw bytes, but there are other explanations, too. (Older/slower code pathway for HTTP in proxy, different intermediate node behavior for HTTP vs TCP from proxy to db, etc. Much less likely, but not impossible.)