Re: [Gnu-arch-users] Fast commits

[Aaron Bentley]

Robin Farine wrote:
> Aaron Bentley wrote:
>
> > I think you missed the "no incompatible changes to the archive format" 
> > rule.
>
>
> Right, older versions of tla would not be able to deal with this new 
> archive format. The reverse would work though.

The "no incompatible changes to the archive format" rule is actually a 
fairly strong component of Arch culture (or The Arch Cult, depending on 
your POV :-).  It's presumed that one day, there may be compelling 
reasons to make a backwards-incompatible change, but until then, all 
changes must be backwards compatible.

(When the time comes for format 2, I'll have some suggestions, for sure.)

> I agree that the LAST-REVISION (or ++last-revision :-) file solution is 
> simpler and completely compatible.  My initial idea was to have the 
> exact last revision atomically updated as part of the commit 
> transaction. But assuming commits with a tla version aware of the 
> LAST_REVISION file happen regularly,  this file would give a starting 
> point not far from the actual last revision. Looks good.

I'm actually curious whether the fact that local filesystem access is 
O(n) is really significant, which is why I'm eager for folks like 
Sallings and Duffy to test whether my commit changes are an improvement 
for them.

Aaron

--
Aaron Bentley
Director of Technology
Panometrics, Inc.