| From: | Jeff Janes <jeff(dot)janes(at)gmail(dot)com> |
|---|---|
| To: | "Sven R(dot) Kunze" <srkunze(at)mail(dot)de> |
| Cc: | "pgsql-performance(at)postgresql(dot)org" <pgsql-performance(at)postgresql(dot)org> |
| Subject: | Re: Speeding up JSON + TSQUERY + GIN |
| Date: | 2017-03-01 17:04:13 |
| Message-ID: | CAMkU=1zYmkgduM75whFbX9mE07juHj+Bkbovhja1wMzFJUpn4A@mail.gmail.com |
| Views: | Raw Message | Whole Thread | Download mbox | Resend email |
| Thread: | |
| Lists: | pgsql-performance |
On Wed, Mar 1, 2017 at 6:02 AM, Sven R. Kunze <srkunze(at)mail(dot)de> wrote:
> On 28.02.2017 17:49, Jeff Janes wrote:
>
> Oh. In my hands, it works very well. I get 70 seconds to do the {age:
> 20} query from pure cold caches, versus 1.4 seconds from cold caches which
> was followed by pg_prewarm('docs','prefetch').
>
> How much RAM do you have? Maybe you don't have enough to hold the table
> in RAM. What kind of IO system? And what OS?
>
>
> On my test system:
>
> RAM: 4GB
> IO: SSD (random_page_cost = 1.0)
> OS: Ubuntu 16.04
>
4GB is not much RAM to be trying to pre-warm this amount of data into.
Towards the end of the pg_prewarm, it is probably evicting data read in by
the earlier part of it.
What is shared_buffers?
Cheers,
Jeff
| From | Date | Subject | |
|---|---|---|---|
| Next Message | Stefan Andreatta | 2017-03-01 22:00:06 | anti-join with small table via text/varchar cannot estimate rows correctly |
| Previous Message | Sven R. Kunze | 2017-03-01 14:02:15 | Re: Speeding up JSON + TSQUERY + GIN |