On Wed, Sep 11, 2013 at 12:27 PM, Bruce Momjian <bruce@momjian.us> wrote:
>> > Another argument in favor: this is a default setting, and by default,
>> > shared_buffers won't be 25% of RAM.
>>
>> So, are you saying you like 4x now?
>
> Here is an arugment for 3x. First, using the documented 25% of RAM, 3x
> puts our effective_cache_size as 75% of RAM, giving us no room for
> kernel, backend memory, and work_mem usage. If anything it should be
> lower than 3x, not higher.
AFAIK, e_c_s must include shared_buffers, so 25% + 75% = 75%
And your statement seems to assume 25% + 75% = 100%. Which isn't
universally true, no matter what your math teacher probably taught you
;-)