Re: _mdfd_getseg can be expensive

On 2016-06-30 18:34:20 -0700, Peter Geoghegan wrote:
> On Thu, Jun 30, 2016 at 6:23 PM, Andres Freund  wrote:
> > I plan to, once the tree opens again. Likely needs some considerable
> > updates for recent changes.
> 
> Offhand, do you think that CREATE INDEX calls to smgrextend() could be
> appreciably affected by this bottleneck? If that's a very involved or
> difficult question, then no need to answer now.

If you have a big enough index (maybe ~150GB+), sure. Before that,
probably not.

It's usually pretty easy to see in cpu profiles whether this issue
exists.

Andres