On Thu, Dec 27, 2018 at 02:44:55PM -0200, Haroldo Kerry wrote: > PostgreSQL 9.6.10 on x86_64-pc-linux-gnu (Debian 9.6.10-1.pgdg80+1), > Connected to SAN: Dell Compellent SC2020, with 7 x Samsung PM1633 SSDs > https://www.samsung.com/us/labs/pdfs/collateral/pm1633-prodoverview-2015.pdf, > RAID10+RAID5 configuration, 8GB Cache, read-write battery backed cache > enabled, connected via dedicated iSCSI switches and dedicated Ethernet > ports, in link aggregation mode (2x1Gbps max bandwidth). > I’m trying to figure out if PostgreSQL (PG) has some inherent limit on IOPS > per connection. postgres uses one server backend per client. > We tried to increase effective_io_size from 1 to 30, to no effect on > multiple tests. https://www.postgresql.org/docs/current/runtime-config-resource.html#RUNTIME-CONFIG-RESOURCE-ASYNC-BEHAVIOR => "Currently, this setting only affects bitmap heap scans." > Is this some inherent limitation of PG or am I misunderstanding something? It is a hsitoric limitation, but nowadays there's parallel query, which uses 2ndary "backend worker" processes. It's supported in v9.6 but much more versatile in v10 and v11. Justin
