On 2018-Aug-13, Don Seiler wrote: > This afternoon I discovered an autovacuum process that had been running for > over 6 days. It was waiting on BufferPin event. I kicked off a manual > vacuum+analyze of the table, which automatically killed that autovacuum. > This ran for a few minutes before it too was waiting on a BufferPin event. > I've never witnessed a vacuum session waiting on BufferPin before. Buffer pins are normally released quickly enough. Of course, an idle-in-transaction session has its own problems, but even those would normally not have buffer pins; so vacuum would run to completion without blocking, even if no tuples would be removed. Maybe you had a cursor that was not fully scanned before the session was left idle -- as I recall, those can leave buffers pinned. -- Álvaro Herrera https://www.2ndQuadrant.com/ PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services
