Обсуждение: shared buffers

Hi,

In the 7.4.5 version, the code is now trying to use a much larger
value for shared_buffers.  I can certainly set this to a lower number
with the -B option.  However, my guestion is:

What is the performance issue with setting shared_buffers to something like 45?

In doing some timing on my system, I cannot tell any difference with 45 versus 1000.
Perhaps I am looking at the wrong performance criteria.

Thanks,
Glenn

Glenn Sullivan <glenn.sullivan@varianinc.com> writes:
> What is the performance issue with setting shared_buffers to something like 45?
> In doing some timing on my system, I cannot tell any difference with 45 versus 1000.

What are you timing exactly?  Almost every benchmark I've ever seen is
much happier with shared_buffers of at least a few hundred.  Otherwise
you spend too much time copying data between kernel and user space.

            regards, tom lane