John R Pierce <pierce@hogranch.com> wrote:
> On 10/9/2014 1:13 PM, Dennis wrote:
>> Hi, a little off the general topic but I am just wondering if the “tar
>> -cf - pgdata | wc -c” trick can be used as general trick to pre-warm
>> the cache?
>
> I wouldn't do this if your pgdata is larger than about 50% of your
> physical ram.
Nor would I do this if pgdata is anywhere near the size of a memory
segment on a NUMA machine. I have seen cache pre-warming through a
single process on NUMA absolutely kill performance.
--
Kevin Grittner
EDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company