[GSoC] migration

[Joshua Root]

On 2017-8-11 21:14 , Umesh Singla wrote:
> Hi
> 
>         And then again, I am sensing a confusion with the idea of
>         snapshot with Josh, like when he says "remove ports when they
>         are no longer referenced by any snapshot".
> 
> 
>     What confusion exactly? A snapshot is simply a set of ports (by
>     which I mean rows in the 'ports' table, with a unique combination of
>     name,version,revision,variants). When nothing references a row any
>     more, it needs to be deleted.
> 
> 
> By 'ports', do you mean 'registry.ports' table? If yes, then I disagree. 
> It's actually 'registry.snapshot_ports' table. A snapshot has nothing to 
> do with the original registry "tables".

That was a suggested design; if you're already doing it differently then 
I guess you don't need a design. I disagree with the last sentence 
though, a snapshot can be viewed as precisely the state of the original 
tables at a previous time.

> Also, we are not using version and revision. Even going by the literal 
> meaning of a snapshot, it should not have a key or id linked to 
> something that can change over time. It's simply the present state.

The row in the ports table would not change over time, it would simply 
persist until no longer needed. If we ever get the ability to install 
old versions then that information would come in handy.

> Later, I am planning to keep information on the manual portgroups in the 
> snapshot, if there are any.

What would this information be used for?

- Josh