It sounds like you've hit the postgres basics, what about some of the linux check list items?
what does free -m show on your db server?
total used free shared buffers cached
Mem: 48295 31673 16622 0 5 12670
-/+ buffers/cache: 18997 29298
Swap: 22852 2382 20470
If the load problem really is being caused by swapping when things really shouldn't be swapping, it could be a matter of adjusting your swappiness - what does cat /proc/sys/vm/swappiness show on your server?
0
We adjusted that too, but no effect.
(I’ve updated the blog post with these two comments)
There are other linux memory management things that can cause postgres and the server running it to throw fits like THP and zone reclaim. I don't have enough info about your system to say they are the cause either, but check out the many postings here and other places on the detrimental effect that those settings *can* have. That would at least give you another angle to investigate.
If there are specific things you’d like to know, I’ve be happy to be a human proxy. :)
Thanks!