On Mon, Jul 05, 2021 at 08:22:39PM -0300, Emiliano Saenz wrote: > We have a huge POSTGRES 9.4 database in the production environment (several > tables have more than 100.000.00 registers). Last two months we have had > problems with CPU utilization. Debugging the locks (on pg_locks) we notice > that sometimes simple UPDATE (by primary key) operation takes out > ACCESS_EXCLUSIVE_LOCK mode over these huge tables so POSTGRES DB collapses > and it generates excessive CPU consumption. My question is, How is it > possible that UPDATE operation takes out ACCESS_EXCLUSIVE_LOCK mode? > More information, this system never manifests this behavior before and we > don't make software changes on last 2 years To be able to help we will need pg_stat_activity data for the for backend that has this lock, and pg_locks information for it too. And, please, send text, and not screenshot. Best regards, depesz