Re: SQL backend database scheme

[Philipp Marek <ph...@emerion.com>]

Hello Jan!

On Mittwoch, 31. März 2010, Jan Horák wrote:
> 30.3.2010 13:55, Philipp Marek wrote:
> > I looked at that, and I'd like to post two wishes:
> >   * Please provide representations with a SHA1 (or similar) field;
> >     then it's possible to split blocks on manber-borders, to save
> >     space.
> 
> Thank you for respond, this is definitely a good point, I will involve it.
Fine, thank you.
Even if no Manber-blocks would be used at first, it would provide consistency 
checks.
 
> >   * Furthermore, how about allowing the plain data to reside in files?
> >     Would make the database much smaller, and then these data blocks
> >     could possibly be shared among multiple repositories.
> >     (Really easy, too, if they're named by their SHA1, for example).
> >     That should allow for zero-copy IO, too (at least for sending data).
> 
> The question is, how much faster it would be.. I would like to make a
> simple test to simulate this soon and estimate the percentage difference..
That would be very interesting to me.
I just know of some similar system where bitmaps were fetched out of a 
database - instead of just using Apache and static paths the whole data was 
transferred multiple times over multiple sockets ...
 
> Another point is a simple backup of the SQL database, using an existed
> global backup system in a company, which is one of the main benefits of
> the SQL backend. Would the external plain data be a problem for global
> backup or not?
That's a good point against that idea, yes.


Regards,

Phil