Re: pgbench initialize

Depends on goals of your benchmarking.
What are you trying to achieve?

Initialization and vacuuming each time will help achieve more consistent
best-case numbers (to reduce variance, I'd also destroy cluster completely
and clean up hardware, e.g. run fstrim in case of SSD, etc).

If you are however after real-world numbers, you may want to initialize
once and run pgbench for hours if not days to get full effects of
autovaccuum and other possible background processes.

On Thu, Dec 15, 2016 at 10:17 PM Anirudh Jayakumar <
jayakumar(dot)anirudh(at)gmail(dot)com> wrote:

> Hi,
>
> I have a couple of questions regarding pgbench. I'm new to PostgreSQL and
> databases in general, so these might be very trivial questions.
>
> 1. Is it necessary to initialize pgbench(-i option) before every run to
> get consistent results?
>
> 2. The vacuuming process after initialize consumes time, what are the ill
> effects of disabling post-initialize vacuuming?
>
> Thanks,
> Anirudh
>