On Wed, Mar 1, 2017 at 6:02 AM, Sven R. Kunze <srkunze@mail.de> wrote:
On 28.02.2017 17:49, Jeff Janes wrote:
Oh. In my hands, it works very well. I get 70 seconds to do the {age: 20} query from pure cold caches, versus 1.4 seconds from cold caches which was followed by pg_prewarm('docs','prefetch').
How much RAM do you have? Maybe you don't have enough to hold the table in RAM. What kind of IO system? And what OS?
4GB is not much RAM to be trying to pre-warm this amount of data into. Towards the end of the pg_prewarm, it is probably evicting data read in by the earlier part of it.
