Re: LMDB and Referential transparency

[Brian Reichert <reichert@numachi.com>]

On Thu, Feb 11, 2016 at 04:16:14PM +0000, Howard Chu wrote:
> Pierre-?tienne Meunier wrote:
> >When I change one of the databases (called for instance A) in my 
> >environment,
> >I'd like to be able to still keep a copy of A as it was before, and make a 
> >new
> >copy B, that would share all its memory with A, except the changes.
> 
> Not likely to happen. The change you're suggesting would require adding a 
> reference counter to every page, among other things. The cost of such a 
> change would be quite high, not worth it for a very obscure feature.

Perhaps explore persisting the LMDB data on a filsystem that supports
snapshots?

Don't know how safe that is, from a DB integrity point-of-view...

> -- 
>   -- Howard Chu
>   CTO, Symas Corp.           http://www.symas.com
>   Director, Highland Sun     http://highlandsun.com/hyc/
>   Chief Architect, OpenLDAP  http://www.openldap.org/project/

-- 
Brian Reichert				<reichert@numachi.com>
BSD admin/developer at large