Hi,
A way to trick EXPLAIN/EXPLAIN ANALYZE to do what you mean is to play
with the optimisation variables:
https://www.postgresql.org/docs/9.6/static/runtime-config-query.html
J.
On 25 November 2017 at 15:01, Adam Tauno Williams
<awilliam@whitemice.org> wrote:
> On Fri, 2017-11-24 at 11:58 -0800, John R Pierce wrote:
>> On 11/24/2017 11:43 AM, Michael Nolan wrote:
>> > There are so many different levels of caching going on--within
>> > Postgresql, within the OS, within a disk array or SAN, and at the
>> > individual drive--that there may no longer be a meaningful way to
>> > perform this measurement.
>> generally, power cycling the server will flush all the hardware
>> caches AND the OS cache.
>
> Given that a real-world application will almost never experience an
> empty-cache scenario I question the usefulness of clearing the
> cache(s). I would capture transactions from a production database in
> order to create a load test that mimics real-world load.
>
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