Re: WIP: Avoid creation of the free space map for small tables

On Wed, Oct 31, 2018 at 1:42 PM John Naylor <jcnaylor(at)gmail(dot)com> wrote:
>
> Upthread I wrote:
>
> > -A possible TODO item is to teach pg_upgrade not to link FSMs for
> > small heaps. I haven't look into the feasibility of that, however.
>
> This turned out to be relatively light weight (0002 attached). I had
> to add relkind to the RelInfo struct and save the size of each heap as
> its transferred. The attached SQL script will setup a couple test
> cases to demonstrate pg_upgrade. Installations with large numbers of
> small tables will be able to see space savings right away.
>
> For 0001, I adjusted the README and docs, and also made some cosmetic
> improvements to the code, mostly in the comments. I've set the
> commitfest entry back to 'needs review'
>
> One thing I noticed is that one behavior on master hasn't changed:
> System catalogs created during bootstrap still have a FSM if they have
> any data. Possibly related, catalogs also have a VM even if they have
> no data at all. This isn't anything to get excited about, but it would
> be nice to investigate, at least so it can be documented. A cursory
> dig hasn't found the cause, but I'll keep doing that as time permits.
>

Thanks for your work on this, I will try to review it during CF.

--
With Regards,
Amit Kapila.
EnterpriseDB: http://www.enterprisedb.com