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Re: Log-addressing branch ready for review

From: Ivan Zhakov <ivan_at_visualsvn.com>
Date: Fri, 29 Nov 2013 20:29:33 +0400

On 28 November 2013 10:22, Stefan Fuhrmann <stefan.fuhrmann_at_wandisco.com> wrote:

>> >
>> > Thanks a lot, Philip!
>> > I plan on merging the branch later this week (Friday-ish).
>> >
>> Well, I still think that log-addressing branch should *NOT* be merged
>> and all FS _performance_ and format changes should be implemented in
>> FSX.
> One more thing. Are you aware that for all we know today,
> move support requires log scans? Probably even for updates.
> This is the very operation that benefits most from format 7.
> And so do merges.
What I'm worry about is bottom-up design approach: we're going to
release fsfs 7 and then someday use it to solve moves and merges.

> I think I fully understand your position. Your concerns are:
> * Minimize code churn (= potential destabilization) in FSFS
> * Protect users against repository corruption.
> * Implement features that users crave for, like full move support.
> The latter two effectively hinge upon format 7. So, let's make
> the first point as little an issue as we can (see below).

>> My primary concern is that currently FSFS supports reading and writing
>> all FSFS formats. And there are more than 6 formats now, because they
>> can differ of how repositories were upgraded. This makes code very
>> complicated, because it should handle all different combinations of
>> formats/upgrades.
> Well, the obvious way to address this concern is to extend
> testing. You may not be aware that running tests on /trunk
> takes only 2:00 min in debug and 1:50 in release. Running
> the test suite [fsfs +svn x all minor server versions] is not
> a problem any longer. (*)
Test suite execution time is developers problem, not users.

> It should also be no problem to test repository upgrades:
> A new option could tell the tests to create the repo in whatever
> old format was selected and then do an 'svnadmin upgrade'
> before running the remainder of the test. Given your observation
> that FSFS format dependencies have already caused trouble
> in the past, adding these kinds of tests is a good idea even
> without format 7,
Let's do proposed test suite improvements first, instead of pushing
changes to trunk. We also need setup buildbots to test all FSFS
formats to prevent problems like we got with revprop packing stuff.

Ivan Zhakov
CTO | VisualSVN | http://www.visualsvn.com
Received on 2013-11-29 17:30:27 CET

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