Re: Parameter value from (mb/gb) to bytes

[Thomas Kellerer <shammat@xxxxxxx>]

Thomas Kellerer schrieb am 14.10.2020 um 15:55:
> Raul Kaubi schrieb am 14.10.2020 um 12:22:
>> Is there a simple way to dynamically get for example parameter
>> „shared buffers“ value (megabytes or gigabytes) to bytes, for
>> monitoring perspective..?>
>>  
>>
>> At the moment, this gives me value in GB.
>>
>> # psql -U postgres -Atc "show shared_buffers;"
>> 1GB
>>
>> This value may as well be in MB. So I am looking a way to dynamically get the value in bytes.
>
> Instead of using "show" you can use a SELECT with pg_size_bytes():
>
>   select pg_size_bytes(setting)
>   from pg_settings
>   where name = 'shared_buffers';

Ah, forgot that shared_buffers is in 8K pages.

So you actually need:

   select pg_size_bytes(setting) * 8192
   from pg_settings
   where name = 'shared_buffers';