Re: [JGIT PATCH 0/4] RepositoryTestCase cleanups

[Robin Rosenberg <robin.rosenberg@dewire.com>]

torsdag 27 november 2008 22:49:16 skrev Shawn O. Pearce:
> Robin Rosenberg <robin.rosenberg@dewire.com> wrote:
> > Ok, so here is an attempt to improve the ability of the JGit's unit
> > tests to delete temporary repositories. This has probably been seen
> > by many, but Jonas Fonseca raised the issue.
> 
> Hmpph.  This takes 19 seconds to run the suite, where it used to be
> only 2 seconds on the same system.  The slower run isn't something
> I'm too happy about, actually I'd like to make the run even faster
> than 2 seconds.

So maybe we should clean up less. Every new test repo we create has
a new name so we could do without cleaning up so much. The cleanup
however is a verification that we close (and can close) our resources, 
though it only works on Windows :/ On unix we could spawn lsof but that
is really really slow. 

> If the issue is mmap'd files, why don't we instead disable mmap
> on Windows during JUnit tests, and use the non-mmap variant of
> pack access?  At least do that for the bulk of the tests, and
> then have a single test case which tests the mmap code path but
> has careful System.gc calls in place to try and ensure we can
> actually clean up the temporary files.
We would then need some other really slow test to play rough with
memory mapping and gc. As I mentioned above it is actually about
closing resources in general, mmapped files being an especially 
nasty case.

> I'd actually like to get that Repository refactoring done soon,
> someone else was asking about it for the RefDatabase (to store the
> refs in a SQL database so JGit ties into JTA) but I may also want
> it for Gerrit 2 - I'm looking at doing something that would put
> 200,000 refs per year into a repository.  That's so large that
> most operations can't afford to scan the entire ref database,
> and it really cannot be loose.  ;-)

Would be cool, but having that diff engine is more important to me.

> 
> 
> Refactoring repository is a fair chunk of work, disabling the mmap
> feature under Windows in JUnit may be easier.  Hmm, according to
> WindowCache's <clinit> its default by false.  Why is it enabling
> on Windows?  The only code that calls WindowCache.reconfigure()
> is in the Eclipse plugin, so pure JGit unit tests shouldn't be
> turning on mmap code *at all*.
> 
> Which also points out a gap in our tests.  Nothing new, we have
> lots of gaps.  *sigh*

Yep.  :/

-- robin