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RE: Format bump for 1.8?

From: Bert Huijben <bert_at_qqmail.nl>
Date: Wed, 11 Jul 2012 16:45:32 +0200

> -----Original Message-----
> From: Johan Corveleyn [mailto:jcorvel_at_gmail.com]
> Sent: woensdag 11 juli 2012 15:51
> To: Greg Stein
> Cc: dev_at_subversion.apache.org
> Subject: Re: Format bump for 1.8?
> 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.

Received on 2012-07-11 16:46:12 CEST

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