On Nov 30, 2012, at 8:06 AM, Shaun Thomas wrote:
I say that because you mentioned you're using Ubuntu 12.04, and we were
having some problems with PG on that platform. With shared_buffers over
4GB, it starts doing really weird things to the memory subsystem.
Whatever it does causes the kernel to purge cache rather aggressively.
We saw a 60% reduction in read IO by reducing shared_buffers to 4GB.
Without as many reads, your writes should be much less disruptive.
Hm, this sounds like something we should look into. Before we start digging do you have more to share, or did you leave it with the "huh, that's weird; this seems to fix it" solution?