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AW: Format bump for 1.8?

From: Markus Schaber <m.schaber_at_3s-software.com>
Date: Thu, 12 Jul 2012 05:47:42 +0000

Hi,

> Von: Bert Huijben [mailto:bert_at_qqmail.nl]
> > From: Johan Corveleyn [mailto:jcorvel_at_gmail.com]
> >
> > I'd like to continue this discussion a bit more, as there are still
> > some things lingering here ...
>
> > Also, as I said, an auto-upgrade needs at least:
> > - To be reversible (need downgrade feature or script).
> > - To be fast, and O(1) (consider 1,000,000 nodes WCs).
>
> Note that there was a repeated expensive table scan in the upgrade process
> for 1.7, which was fixed in r1342984 and merged back to 1.7.x in r1349817,
> but still not released.
>
> O(1) is impossible for most database schema changes except adding empty
> tables, but O(n) should be doable. (Creating an index on some data is more
> expensive than O(n), and simply changing every record O(n)) The 1.7
> upgrade was O(n^2), until r1342984.
>
> The format bump required for conflict skels is currently still O(n),
> except for adding an index on the file move a fields that are always NULL
> in 1.7.

One of the most annoying things in the upgrade from 1.6 to 1.7 was that certain conditions prevented a successful update, and which could not be solved without an 1.6 client.

Most of those were fixed as bugs, (like lock tokens in the local wc), but a major one remained: working copies needing a "cleanup".

From an users perspective, it is a very annoying experience when he upgrades his SVN client(s), and then some days later stumbles across a working copy which he cannot upgrade without downgrading one of his clients.

As the 1.7 and 1.8 working copy format changes are only "minor" ones from an architectural view, do you think the upgrade could handle this case better this time?

Best regards

Markus Schaber

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Received on 2012-07-12 07:48:26 CEST

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