+1. I was thinking can we move the logic of checking if bg workers are the
reason of blocking the main backend inside pg_isolation_test_session_is_blocked
to make it cleaner, and regarding "XXX Should we use a separate query for that?"
i am confused here IIUC if we keep it as 1 query using UNION every time its for sure
that both the queries will run, which can increase more execution time but less libpq/socket
calls, but if we send as 2 queries if 1st query doesn't returns true we have to go and
check the other query, so here if 2 queries ran then execution + libpq/socket calls overhead,
so i am slightly inclined towards separating the queries , so that if 1st gets satisfied then
we don't touch the 2nd query at all, please correct me if i am wrong here :)