On Wed, Oct 9, 2013 at 05:01:24PM +0200, Pavel Stehule wrote: > FYI, this auto-tuning is not for us, who understand the parameters and > how they interact, but for the 90% of our users who would benefit from > better defaults. It is true that there might now be cases where you > would need to _reduce_ work_mem from its default, but I think the new > computed default will be better for most users. > > > > then we should to use as base a how much dedicated RAM is for PG - not shared > buffers.
Yes, that was Josh Berkus's suggestion, and we can switch to that, though it requires a new GUC parameter, and then shared_buffers gets tuned on that.
I went with shared_buffers because unlike the others, it is a fixed allocation quantity, while the other are much more variable and harder to set. I figured we could keep our 25% estimate of shared_buffers and everything else would fall in line.
I understand, but your proposal change a logic to opposite direction. Maybe better is wait to new GUC parameter, and then implement this feature, so be logical and simply understandable.
