Re: checkpoints taking much longer than expected

On Sat, Jun 15, 2019 at 4:50 AM Tiemen Ruiten <t(dot)ruiten(at)tech-lab(dot)io> wrote:

>
> On Fri, Jun 14, 2019 at 5:43 PM Stephen Frost <sfrost(at)snowman(dot)net> wrote:
>
>>
>> The time information is all there and it tells you what it's doing and
>> how much had to be done... If you're unhappy with how long it takes to
>> write out gigabytes of data and fsync hundreds of files, talk to your
>> storage people...
>>
>
Right, but true only because they were "checkpoint starting: immediate".
Otherwise the reported write time includes intentional sleeps added to
honor the checkpoint_completion_target. A bit confusing to report it that
way, I think.

I am the storage people too :)
>

So, what did you say to yourself? Have you done fundamental benchmarking
at the OS level, to see how fast you can write out 1-2 GB of data changes
spread out randomly over a few hundred GB of data, when it is not coming
from PostgreSQL?

Cheers,

Jeff