Re: Sanity check of shared_buffers value

You can use:

https://pgtune.leopard.in.ua/

for your cal.

Thanks,
-J

On Mon, Jul 3, 2023 at 4:46 PM Ron <ronljohnsonjr(at)gmail(dot)com> wrote:

> Being AWS RDS is the kind of thing you need to mention.
>
> Anyway, plain old bash bc does it for you. Explicitly:
> (24*1024^3)/1024/8
>
> Powershell, too:
> 24*[bigint]::pow(1024,3)/1024/8
>
> On 7/3/23 14:57, Wells Oliver wrote:
>
> Yeah. Unfortunately in AWS RDS the parameter group settings accept input
> only in stricter format, so shared_buffers requires an integer value in KiB.
>
> On Mon, Jul 3, 2023 at 12:56 PM Ron <ronljohnsonjr(at)gmail(dot)com> wrote:
>
>> On 7/3/23 14:45, Wells Oliver wrote:
>>
>> Sorry, this is dumb, but I wanted to double check that I'm doing the
>> shared_buffers calc correctly given it's in 8kb blocks (block_size is set
>> to 8192).
>>
>> Want 24GB, which I think is 25165824 KiB so divided by 8 we get 3145728.
>>
>> Do I have this correct? Usually can test these but wanted to run it by
>> someone before having to restart the server.
>>
>> Is there some calc web service out there that idiots such as myself can
>> use for this?
>>
>>
>> https://www.postgresql.org/docs/15/runtime-config-resource.html
>>
>> "If this value is specified *without **units*, it is taken as blocks,"
>>
>> My interpretation of this (and what I do in my postgresql.conf file,
>> without error) is to use a unit name, as such:
>> shared_buffers = 24GB
>>
>> --
>> Born in Arizona, moved to Babylonia.
>>
>
>
> --
> Wells Oliver
> wells(dot)oliver(at)gmail(dot)com <wellsoliver(at)gmail(dot)com>
>
>
> --
> Born in Arizona, moved to Babylonia.
>