[PATCH 11 of 11 V1] store: implement new fncache2 requirement
mpm at selenic.com
Tue Oct 2 16:07:23 CDT 2012
On Tue, 2012-10-02 at 11:40 +0200, Pierre-Yves David wrote:
> On Mon, Oct 01, 2012 at 06:36:05PM +0200, Adrian Buehlmann wrote:
> > On 2012-10-01 12:42, Pierre-Yves David wrote:
> > > On Sun, Sep 30, 2012 at 11:56:48PM +0200, Adrian Buehlmann wrote:
> > >> # HG changeset patch
> > >> # User Adrian Buehlmann <adrian at cadifra.com>
> > >> # Date 1349033428 -7200
> > >> # Node ID 6a4d27efb2127f622b3a42037ae5340999c60109
> > >> # Parent efbc439c7f2cb97ff04ada6edd78dce186a72118
> > >> store: implement new fncache2 requirement
> > >>
> > >> not yet used
> > >
> > > About that:
> > >
> > > Even if we have a much better requires message in recent version I think we
> > > should keep this disabled by default for a few version. People who need it will
> > > explicitly enable it and provides useful feedback before we turn is on by
> > > default.
> > That's not how repository layout changes have been released in the past.
> And a major source of complain from our user.
> We do not do that since 1.9 and generaldelta
> (Ok general delta is a bit special and there are still good reasons to keep it
> disabled for now)
> > I don't see why this one would be different.
> > If you improve software, you need to put it to use. Otherwise it's
> > pointless.
> > This is not an experimental format change. It is intended as the new
> > standard for Mercurial repositories.
> > No user will use this format, if it's not the default.
> I do not advocate to turn it off forever. I advertise to turn it off for a few version.
> - That'll give time for early adopter to catch some bug.
> - By then we'll have much more people using at least 1.9 (eg: debian squeeze
> have 1.6, wheezy have 2.2)
> 1.9 have a proper error message when it encounter missing requirement. Prior
> to that the message is unclear and very frustrating.
> As far as I understood it, this new format mostly aims for simplification,
> performance improvement and rare coner case handling. We are not in hurry to
> make it the default.
Adrian's right (and he should know, having instigated the last two
changes), that's not how we've done format changes in the past, and
probably not how we'd deal with this transition either, if and when we
decide to make it.
On the other hand, the only thing pushing this particular change is
performance, so I'm in no great hurry to make a switch. I'd rather
gather up a few more format improvements to go with it (for instance,
dropping all the redundant data/ and .i in .hg/store/fncache). Probably
the right time to make that decision is at the beginning of a dev cycle
so we can have all the wrinkles ironed out. I also like to space out the
introduction of new C code and we just added a bunch.
Mathematics is the supreme nostalgia of our time.
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