Re: Remaining beta blockers

On Fri, May  3, 2013 at 05:24:54PM +0200, Andres Freund wrote:
> On 2013-05-03 16:11:13 +0100, Greg Stark wrote:
> > On Fri, May 3, 2013 at 1:12 AM, Bruce Momjian <bruce@momjian.us> wrote:
> > > I was more thinking of the idea of having some status on the first page
> > > that might need to change in a future release.
> > 
> > Incidentally, another option might be to have a <relfilenode>.meta
> > fork that has information like this. It doesn't fundamentally change
> > anything but it does mean that code that doesn't need to know about it
> > doesn't need to know to skip the first page. It also means  we could
> > maybe expand it more easily. There have been previous wishlist items
> > to have some meta information so external tools can more easily parse
> > the data without needing access to the full catalog for example.
> 
> The problem with an extra metadata fork is that it essentially would
> double the files in a cluster and it would also noticeably increase the
> amount of open files we need.
> There have been quite some complaints about CREATE DATABASE speed, I
> am not sure we want to make it even slower :(

Agreed.  We start to get into file system performance issues at that
point.  I have often wondered if we need to create hash the files into
subdirectories for databases with many tables.  Has anyone profiled
this?

--  Bruce Momjian  <bruce@momjian.us>        http://momjian.us EnterpriseDB
http://enterprisedb.com
 + It's impossible for everything to be true. +