Re: basic question (shared buffers vs. effective cache

scott.marlowe wrote:
>
> shared_buffers is the amount of space postgresql can use as temp memory
> space to put together result sets.  It is not intended as a cache, and
> once the last backend holding open a buffer space shuts down, the
> information in that buffer is lost.  If you're working on several large
> data sets in a row, the buffer currently operates FIFO when dumping old
> references to make room for the incoming data.
>
> Contrast this to the linux or BSD kernels, which cache everything they can
> in the "spare" memory of the computer.  This cache is maintained until
> some other process requests enough memory to make the kernel give up some
> of the otherwise unused memory, or something new pushes out something old.

Do checkpoints operate on the Postgres-managed buffer, or the kernel-managed
cache?

Jack Orenstein