Re: [Issue 1585] Deltified dumps for archival and schema conversion

On Mon 2004-06-21 at 15:07:02 -0400, Mikhail Terekhov wrote:
> >As for using deltas in the dumps -- "svnadmin load" won't simply store
> >those back into the repository. It'll recreate the current fulltext
> >and apply that. The deltas are for space, not time efficiency.
>
> You lost me here. Do you mean that "svnadmin load" first recreates
> full text from delta and then does exactly the same as in the case
> with full text dump (i.e. calculate delta again)?

Yes, it will create the fulltext, put that into the repository and the
repository (library) will calculate a delta again. But it sounds as if
you think it is the same delta that was in the dumpfile. It isn't.

Regardless of whether the delta algorithm is the same (I don't know
without checking, but I don't see a reason for using two different
ones here), there is a difference of what is diff'ed against what.

Say the notation (a,b) means a delta that transforms a file from
version a into b. Then an incremental dump contains deltas of the form

  (1,2) (2,3) (3,4) and so on (that is, deltas against the older revision)

while the repository (BDB backend) stores deltas like this:

  (2,1) (3,2) (4,3) and so on (i.e. deltas against the younger revision)

Bye,

        Benjamin.

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Received on Wed Jun 23 01:24:33 2004