Re: Lock contention (was Re: [PATCHES] update i386

Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> writes:
> LRU etc have nothing to do with this. The majority of trips into the
> buffer manager are for ReadBuffer/ReleaseBuffer. What we need is to
> figure a way for those operations to use finer-grain locks so they don't
> contend so much.

I reimplemented much of bufmgr.c over the holidays, with the goal of
reducing the contention for the BufMgrLock as well as fixing some
other less important problems. Where possible, operations that only
effect the state of a single buffer now only need to acquire a
per-buffer "meta data lock". I haven't done any benchmarking yet, but
this should hopefully improve concurrent performance. The patch isn't
quite finished yet, but I'll post it to the list in a few days once
I've had a chance to wrap up a few loose ends.

-Neil