hg-git converted repo is massive

[Kastner Masilko, Friedrich]

> From: mercurial-bounces at selenic.com [mailto:mercurial-bounces at selenic.com] On Behalf Of v
> 
> Kastner Masilko, Friedrich-2 wrote
> > With some tweaks to the revlog class, you can get a kernel-repo clone
> > down to 2GB, but it would cost you in terms of speed. I've submitted
> > an appropriate patch to the crew, but Matt rejected it with a very
> > plausible explanation in this devel-list thread:
> > http://selenic.com/pipermail/mercurial-devel/2012-July/042600.html .
> 
> It seems that mercurial is optimised for mechanical discs, but a
> mutually exclusive optimisation is needed for SDDs (space is expensive
> but random access is cheap). Could this be an option to configure when
> the repository is created, similar to the way that MySQL lets you
> choose a storage engine when creating a database? (Obviously not quite
> the same, because the UI would be identical either way - it's only the
> internal storage algorithms that have changed.)

The patch itself is only affecting the revlog creation. As long as it is applied, every commit in a repository with the appropriate format flag will be calculated accordingly. If it is unapplied, following commits will create "normal" revlog additions again. The thing is: every Mercurial installation will suffer/benefit from the same effects for the portions in the revlog created that way, whether or not the patch is installed. It is no on/off feature, so to say, just a way to create more compact revlogs, trading storage space for seek count.

It could certainly be a similar option as the parentdelta (or is it generaldelta now?) format switch.

Regards,
Face



Development Software Systems
Festo Gesellschaft m.b.H.
Linzer Strasse 227
Austria - 1140 Wien

Firmenbuch Wien
FN 38435y
UID: ATU14650108

Tel: +43(1)91075-198
Fax: +43(1)91075-282
www.festo.at

Der Inhalt dieses E-Mails ist ausschliesslich fuer den bezeichneten Adressaten bestimmt. Jede Form der Kenntnisnahme,
Veroeffentlichung, Vervielfaeltigung oder Weitergabe des Inhalts dieses E-Mails durch unberechtigte Dritte ist unzulaessig. Wir
bitten Sie, sich mit dem Absender des E-Mails in Verbindung zu setzen, falls Sie nicht der Adressat dieses E-Mails sind und das
Material von Ihrem Computer zu loeschen. 

This e-mail and any attachments are confidential and intended solely for the addressee. The perusal, publication, copying or
dissemination of the contents of this e-mail by unauthorised third parties is prohibited. If you are not the intended recipient of this
e-mail, please delete it and immediately notify the sender.