On Wed, Jun 13, 2018 at 11:45 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:
>> I have tested wal_prefetch at two powerful servers with 24 cores, 3Tb NVME
>> RAID 10 storage device and 256Gb of RAM connected using InfiniBand.
>> The speed of synchronous replication between two nodes is increased from 56k
>> TPS to 60k TPS (on pgbench with scale 1000).
>
> That's a reasonable improvement.
Somehow I would have expected more. That's only a 7% speedup.
I am also surprised that HDD didn't show any improvement. Since HDD's
are bad at random I/O, I would have expected prefetching to help more
in that case.
--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company