Re: _mdfd_getseg can be expensive

On 2016-08-31 14:09:47 -0700, Peter Geoghegan wrote:
> 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.

Thanks for looking!


> 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.

I can't really see that being worth the code here. The cost of
open()/lseek()'ing etc. is going to dwarf the cost of this.


Regards,

Andres