What steps will reproduce the problem?
1. Create a VSS database
2. Add a binary file of 10MB in it
3. Create 300 revisions of the file in VSS using check out, change the file a
bit, check in.
4. Convert this database using vss2git
What is the expected output? What do you see instead?
The output of vss2git is correct as far as I can see. However the process takes
extremely long (weeks). Scanning the database is fast (<1 minute), but each
revision takes in the order of hours.
What version of the product are you using? On what operating system?
1.0.10.0, Windows 8.1
Please provide any additional information below.
This is a special case, because usually a version control database will contain
many smaller (textual) files with a small amount of changes. In this case the
VSS database I work with contains MS Access databases (MDB files) which can
only be saved monolithically. Hence the large set of revisions for a large
binary file.
I debugged the process in Visual Studio 2013. The long time for processing each
revision is spent, on a high level, like this:
* Process a revision for MyBinaryFile.bin, for example revision 1
* VssFileRevision.GetContents() - for revision 1
* Get the last revision for MyBinaryFile.bin, for example 300
* Loop until we're at revision 1
* Get the delta operations for revision 300
* Merge them with revision 1
* Get the previous revision, 299
* .. etc, until we're at the revision we want (revision 1)
* Return the contents of the result of all the merges
The Merge operation is very expensive, it takes multiple minutes. And because
of the large amount of revisions and the way this loop is set up, it is
executed many times.
I don't understand enough of the structure of VSS databases and of vss2git to
be able to see whether all of these steps are essential and how they could be
optimized. I do know that converting the database I'm working with is not
practical because it takes far too long.
Original issue reported on code.google.com by
aron.mul...@gmail.comon 12 Feb 2015 at 12:45