James Sewell <james.sewell@xxxxxxxxxxxx> writes: >> I'm also wondering a bit about whether they're being blocked on a lock, >> eg. due to something taking an exclusive lock on pg_authid or pg_database. >> pg_locks might be interesting to check. > postgres=# select * from pg_locks where not granted; The hypothesis I'm thinking of is that incoming sessions are being blocked somewhere before they can acquire a ProcArray entry; if so, they'd not show up in either pg_stat_activity or pg_locks. What we have to look for then is evidence of somebody holding a strong lock on a shared relation. Try "select * from pg_locks where locktype = 'relation' and database = 0". regards, tom lane
