Re: Thinking about breaking up the BufMgrLock

"Simon Riggs" <simon(at)2ndquadrant(dot)com> writes:
> After much thought, I believe the best way is to implement bufferpools
> (BPs). That is, we don't just have one bufferhash and one LRU, we have
> many pairs. We then work out some mapping by which a block can be known
> to be in a particular BP, then acquire the lock for that BP.

I think this is basically wrongheaded, because it achieves its reduction
in contention by a one-for-one sacrifice of cache allocation efficiency;
that is, any individual page is now fighting for survival in a pool only
1/Nth as large as before. We're going to lose more in I/O than we can
hope to save at the processor level.

I think a clock algorithm or something similar may be a reasonable way
to go, though.

regards, tom lane