Setup: * PostgreSQL 9.3.9 * 1 master, 1 replica * Tiny database, under 0.5GB, completely cached in shared_buffers * 90% read query traffic, which is handled by replica * Traffic in the 1000's QPS. The wierdness: Periodically the master runs an "update all rows" query on the main table in the database. When this update hits the replica via replication stream, *some* (about 5%) of the queries which do seq scans will stall for 22 to 32 seconds (these queries normally take about 75ms). Queries which do index scans seem not to be affected. Thing is, the update all rows only takes 2.5 seconds to execute on the master. So even if the update is blocking the seq scans on the replica (and I can't see why it would), it should only block them for < 3 seconds. Anyone seen anything like this? -- Josh Berkus PostgreSQL Experts Inc. http://pgexperts.com -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
