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Fwd: Revprop packing implemented

From: Stefan Fuhrmann <stefan.fuhrmann_at_wandisco.com>
Date: Mon, 9 Jul 2012 11:06:58 +0200

Effing gmail :(

On Sun, Jul 8, 2012 at 2:28 AM, Hyrum K Wright <hyrum_at_hyrumwright.org>wrote:

> On Fri, Jul 6, 2012 at 3:32 AM, Stefan Fuhrmann
> <stefan.fuhrmann_at_wandisco.com> wrote:
> > Hi devs,
> >
> > This week I had one of my "how hard can it be?" moments
> > and finally implemented revprop packing (did that mainly
> > offline). It passes all tests and seems to work pretty well.
> >
> > It's design deviates from the existing revprop packing branch
> > in that it is more scalable and simpler to implement. Key
> > differences:
> >
> > * Have a configurable limit (default 64k) to the pack file size.
> > Concatenate revprops only up to that limit, but at least one
> > revision's revprops per file. Have the manifest map revs to
> > revprop pack files. IOW, let the OS do all the heavy lifting
> > of storage management.
> > * Make revprop packing a mandatory part of FSFS packing
> > in format 6 repos. There is no need to track revprop packing
> > separately nor to give it a separate format info.
> Do you have an overview of the entire design, rather than just a delta
> between your implementation and the existing one?
> subversion/libsvn_fs_fs/structure explains more of it.

Beyond that, there is no specific design. The core ideas are

* limited pack file size
* separate manifest file & folders as with revision data packing
* single-file-move-into-place semantics when writing revprops
  (as today with non-packed revprops)

I.e. we combine proven parts of revision data packing and
non-packed revprop handling. Everything else is just "data

-- Stefan^2.

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Received on 2012-07-09 11:07:31 CEST

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