Re: WAL prefetch

On Thu, Jun 14, 2018 at 6:14 PM, Robert Haas <robertmhaas@gmail.com> wrote:
> 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.
>

It might be due to the reason that there is already a big overhead of
synchronous mode of replication that it didn't show a big speedup.  We
might want to try recovery (PITR) or maybe async replication to see if
we see any better numbers.

-- 
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com