Marc Millas <marc.millas@mokadb.com> writes:
> I am looking at a postgres 9.6 on rh7
> I see that checkpoint_write_time is huge which looks quite strange as the
> average amount of data written is not that big.
checkpoint_write_time is not the amount of time spent doing I/O;
it's the elapsed wall-clock time in the write phase. If the I/O
is being throttled because of an un-aggressive checkpoint completion
target, it could be a lot more than the actual I/O time. What have
you got your checkpoint parameters set to?
regards, tom lane