Re: _mdfd_getseg can be expensive

On Thu, Aug 18, 2016 at 5:26 PM, Andres Freund <andres@anarazel.de> wrote:
> Rebased version attached. A review would be welcome. Plan to push this
> forward otherwise in the not too far away future.

This looks good.

The only thing that stuck out to any degree is that we don't grow the
"reln->md_seg_fds[forknum]" array within the new _fdvec_resize()
function geometrically. In other words, we don't separately keep track
of the array size and allocated size, and grow the allocated size
using the doubling strategy that you see in many places.

Now, I freely admit that that probably doesn't matter, given what that
array tracks. I'm just pointing out that that aspect did give me
pause. The struct MdfdVec is small enough that that *might* be
worthwhile.

-- 
Peter Geoghegan