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Re: AW: AW: How to check integrity of database?

From: Matt England <mengland_at_mengland.net>
Date: 2005-10-05 17:35:12 CEST

At 10/5/2005 10:12 AM, Paul Koning wrote:
>As Matt England pointed out, if this is what you're worried about, the
>only answer is going to be to generate and save checksums (md5sum or
>better) for every file. You can then regenerate them and check for

I was hoping that Subversion 1.2.x or above does this
automatically. Earlier parts of this thread suggested so...but I'm still
not sure. imho, I'm concerned that there may be "checksuming" going on
for what I'm calling "meta data" (revision properties, internal svn
file-system stuff, etc) and not necessarily the actual file-revision
content data (be it incremental data or not).

Paul, your post possibly suggests that data-checksumming is not happening
in Subversion.

Gary suggests otherwise:

At 10/5/2005 09:48 AM, Gary Thomas wrote:
>There's no such distinction (as far as I can tell). What's kept
>are representations of the "revision" which contains information
>from how to get from one revision to another. The actual file(s)
>do not have a separate representation within the native file system.

I'm reading from this note that all the file properities and other data
gets "mushed" together with all the file content, and an entire checksum is
done on that...which seems like a pretty good thing from what I can tell.

I'm hoping to get an authoritative response on this stuff from developers
or other suitable stakeholders. It's a pretty important point, imho.

An aside about data-integrity problems in storage and computing
systems: having worked in the enterprise-storage industry for quite a
while, I've seen a lot of data integrity issues. I've seen a lot of
hardware-based ones, but I've also seen data-integrity failures generated
from software/firmware things, too. Depending on the system and
environment, I find it hard to necessarily say one thing or another
"causes" data integrity issues. As usual, sometimes it's cobmination of
things, too...and fingers like to point all over the place when it happens.

I don't want this to necessarily turn into a "how do data integrity
violations" happen thread, so I'll bow out of that point from here on out
and await word on Subversion's means to address it if it were to happen in
any case.


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Received on Wed Oct 5 17:37:34 2005

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