script runs slower and slower when rev number increases

[Benoit Boissinot]

On Thu, Oct 29, 2009 at 9:25 AM, Max (Weijun) Wang <Weijun.Wang at sun.com> wrote:
> Hi All

Hi Max,

>
> I write a shell script to call 'hg cat -r n filename'. n is in a range
> from 0 to 110000 and I'm sure that filename in a newly added file for
> changeset n. Therefore, I guess no matter how big n is, the command
> should not waste a lot of time, since it always prints out the first
> version of that file. The actual thing is, when n goes bigger, the
> command becomes very very slow. I change n to the changeset hex number
> but it's even slower.

Two things:
- if you describe what your high-level goal is, we could probably help
you (and write a python extension for that maybe)
- is it possible for you to find where the time is spent (with hg --profile)?

>
> Maybe hg always go into the changeset history to cat a file?
It does since it has to follow the chain changelog -> manifest -> filelog

> Is there a way I can speed up the process?

Maybe hg debugdata directly on the filelog (in .hg/store/data/...).

regards,

Benoit