Re: SVN working copy split DB vs. working area

Brane:

Good to hear from you!

On Wed, Apr 11, 2018 at 2:57 PM, Branko Čibej <brane_at_apache.org> wrote:

> On 11.04.2018 20:27, Doug Robinson wrote:
> > I've now seen a request for this twice in as many days. Once from
> > a customer and once from someone posting to a Subversion forum
> > here:
> >
> > https://www.svnforum.org/forum/opensource-subversion-
> forums/apache-subversion-1-8-support/80218-subversion-
> checkout-on-distrubuted-filesytem
> >
> > The general setup is that they want to have a working copy on a
> > Distributed File System (DFS, e.g. Lustre) and the DFS either is
> > very slow (when mounted with sufficient support for SQLite) or just
> > does not work due to a lack of support for SQLite - likely locking).
> >
> > One set of folks want to accelerate by doing parallel checkouts the
> > way they could do using SVN 1.6 (prior to the consolidated ".svn"
> > tree). But SQLite locking will prevent that (unless I'm missing
> > something).
> >
> > Another set of folks is ok for having the ".svn" area on a local
> > file system (e.g. ext4) but want the rest of the working copy out
> > there on the DFS.
> >
> > NOTE: both sets of folks are experienced SVN users. Both know and
> > have rejected "exporting" - they want a working copy.
> >
> > Has this subject come up before? Is there a way to link a ".svn"
> > area to the rest of the working copy? In other words, keeping the
> > housekeeping area separate/split from the rest of the working copy?
>
> One of the original design goals for the SQLite-based working copy was
> that the database could be hoisted out of the working copy proper and
> that multiple working copies could share the same database. However,
> there has been no real work done toward that goal.
>
> It's possible to move the .svn/wc.db database elsewhere and replace it
> with a symbolic link to the original database. However, I'm not too sure
> how that will help, since the SQLite journal files will still be created
> in .svn/. Also, this would have to be done manually for every external
> directory (which currently has its own, separate .svn/ directory).
>

Simple enough experiment for them to try - I'll suggest it to them.

Especially when I combine it with an observation made by Julian that a
WC with the .svn and zero other files can be tar'd up and copied and
then re-populated. If the payback is large enough then perhaps...

Cheers!

Doug

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