Re: Question about buffers_alloc in pg_stat_bgwriter view for monitoring

On 29/03/2018 20:24, Alvar Freude wrote:
> Hi,
>
>> Am 29.03.2018 um 10:30 schrieb Gunnar Nick Bluth <gunnar(dot)bluth(at)pro-open(dot)de>:
>>
>> Thus, buffer_alloc is the global count of buffers allocated in the
>> cluster. That it appears in the bgwriter statistics is more or less
>> coincidental.
> But it seems not to be the total shared_buffers used, but the total number of allocated and re-allocated buffers. So it increments every time a buffer is allocated. Maybe I’m the only one who misunderstands it – or someone with better english then me should update the docs. ;-)
>
But shared_buffers represents the max no of postgresql buffers, per server, at any given time. It is a limit (constant) not a metric. The count of all concurrent buffers at any given time must be less
than shared_buffers.
So my question is : Does buffer_alloc represent the total read/write traffic of the database since the last reset?
>
> Ciao
> Alvar
>
> --
> Alvar C.H. Freude | http://alvar.a-blast.org
> https://blog.alvar-freude.de/
> https://www.wen-waehlen.de/

--
Achilleas Mantzios
IT DEV Lead
IT DEPT
Dynacom Tankers Mgmt