Re: From P4 to Git

[Alex Riesen <raa.lkml@gmail.com>]

On Mon, Aug 3, 2009 at 13:30, Sam Vilain<sam@vilain.net> wrote:
> On Mon, 2009-08-03 at 10:47 +0200, Alex Riesen wrote:
>> Is it an import-once tool, or can the process be restarted? (because it looks
>> like the script needs a complicated setup).
>
> It's fully restartable.  Not only that but it uses transaction
> protection to make sure that its internal state doesn't get corrupted
> when performing the various options.

"varios options"? Operations? As when working on a live server?
Aren't P4 changelist numbers always increasing? Or you mean
the protection against multiple running instances of p4raw,
so it is also parallelizable?

>> Can it be used from a client machine?
>>  And more importantly:
>> can the branches be found from incomplete history,
>> restricted by path and changelist range? (because, in a corporate
>> setup, clients seldom have full access to all data).
>
> No, it's server only. ...

Darn. I hoped it wasn't. Can't play with it, then.

> ... I think I did get around to implementing not having
> to go through all the stages for branches you didn't care to import.  It's
> difficult though, the stage which correlates those thousands of 'integrate'
> records is never going to be fast.

Maybe if it is done locally, it can be improved? You seem to use the
Postgre for lookups, right?

> Be prepared to tune your postgres - add lots of shared_buffers and
> sort memory if your project is as large as Perl.

Mine isn't, but it is thrown on a server with a lot of others. Some branched
off mine, some integrate it, some just copied and re-introduced into repository
(these will probably worked with manually forever). There is also a small
problem of different P4 servers, hosting code from the same project (they
pull different repos together on client, imagine that!)

And all of them go back for 5-6 years, so it is kind of largish (not to mention
a mess of binaries).

Some branches I hope to merge back. I do that already, but it is a lot of
manual work (I use that git-p4-import.bat I posted early, which only can
import a sequence of changelists with files they touch).

That's were I hoped your project could help. I thought, if I pull in all the
needed changelists (selected by path/CL), there may be a way to
recreate a mergeable history out of this dump. At least, one involving less
labor then I have to do now.