Hi Melvin
From: Melvin Davidson [mailto:melvin6...@gmail.com]
Sent: Donnerstag, 31. Mai 2018 15:53
To: Charles Clavadetscher
Cc: pgsql-generallists.postgresql.org
Subject: Re: Question on disk contention
On Thu, May 31, 2018 at 1:13 AM, Charles Clavadetscher
mailto:clavadetsc
For the sake of completeness I think i have to slightly correct myself.
While I cannot find it in the documentation, (if somebody has pointers, please
provide them) on my personal notes I found that 'if a scan is already in
progress, and a new scan starts, then the new scan will start where the
As far as I know, the OS cache is shared, and shared_buffers too.
Back to the matter of contention, your statement i think might be true only in
cases when you are querying data which does not fit in RAM.
Under those circumstances, the OS or Postgres might need to evict blocks from
RAM to make
> Why isn't the OS caching the disk blocks, and why isn't Postgres using the
> cached data?
It does, but the cache is for each connection/job. They are not shared.
--
Melvin Davidson
Maj. Database & Exploration Specialist
Universe Exploration Command – UXC
Employment by invitation only!
That
On Thu, May 31, 2018 at 10:04 AM, Ron wrote:
> On 05/31/2018 08:52 AM, Melvin Davidson wrote:
>
>
>
> On Thu, May 31, 2018 at 1:13 AM, Charles Clavadetscher <
> clavadetsc...@swisspug.org> wrote:
>
>> Hi Melvin
>>
>> As an answer to a previous post you wrote:
>>
>> "Also, your main problem is tha
On 05/31/2018 08:52 AM, Melvin Davidson wrote:
On Thu, May 31, 2018 at 1:13 AM, Charles Clavadetscher
mailto:clavadetsc...@swisspug.org>> wrote:
Hi Melvin
As an answer to a previous post you wrote:
"Also, your main problem is that when you have two exact same queries
execut
On Thu, May 31, 2018 at 1:13 AM, Charles Clavadetscher <
clavadetsc...@swisspug.org> wrote:
> Hi Melvin
>
> As an answer to a previous post you wrote:
>
> "Also, your main problem is that when you have two exact same queries
> executing at the same time, they will cause contention in
> the disk, a
Hi Melvin
As an answer to a previous post you wrote:
"Also, your main problem is that when you have two exact same queries executing
at the same time, they will cause contention in
the disk, and neither one will make much progress."
Could you elaborate a little more on the meaning of "contentio
