RE: SlikSVN 1.6.6 64-bit stalls on some operations

> Van: Jason R. Coombs [mailto:jaraco_at_jaraco.com]
>
> Greetings.
>
>                 I've run into an issue with the latest release of SlikSVN
> (1.6.6). I'm copying the problem description from an earlier mail to the
> SlikSVN team, as the SlikSVN team has suggested I contact this list for
> suggestions.
>
>                 I've been using SlikSVN for all of my 64-bit Windows systems.
> Beginning with 1.6.6, I found that the svn client frequently stalls, for 120
> seconds or more, on certain operations. It seems to stall in particular at
> the following places:
>
> 1)            At the beginning of a checkout operation, before copying any
> files.
> 2)            At the end of an import or checkin operation, after the server
> has completed the transaction, but before the client reports the new revision
> number.
> 3)            At the end of an list operation, before returning control to
> the parent process.
> 4)            At the end of some update operations, before returning control
> to the parent process.
>
> While the client is stalling, I can check the network connections and
> see that a TCP connection is open to the server, so the problem appears to be
> related to some I/O blocking.
>
> I've only observed this problem when working against my server, though
> I spend only a small amount of time working with other servers. I haven't
> been able to replicate the issue with Google or Sourceforge HTTPS servers. My
> server is running SVN 1.6.6 on Apache 2.2.14 behind IIS via ISAPI Rewrite.
>
> I do not experience the issue with the Tigris.org 1.6.6 svn client nor
> with TortoiseSVN 1.6.6 client. I always experience the problem with the 32-
> bit and 64-bit SlikSVN clients.
>
> The problem can be easily replicated by requesting a list operation on
> https://svn.jaraco.com/jaraco/python with the SlikSVN 1.6.6 client.
> Obviously, the problem seems to be related to my server configuration as
> well, but because the problem emerged with the latest release of the client,
> and since the server works well with other clients, it makes the most sense
> to determine what changed with the client.
>
> The SlikSVN team has suggested I write this list to see if you have
> any suggestions as to what might be causing the stalls. I suspect the problem
> has something to do with the way that the I/O is handled. The problem emerged
> with 1.6.6 and goes away if I roll back to SlikSVN 1.6.5.
>
> Was there any change in the Subversion 1.6.5-1.6.6 changeset that
> might affect the I/O behavior as described?
>
>                 Do you have any other suggestions for troubleshooting this
> issue?

That is ... weird. Especially the fact that you only get the issue with SlikSVN 1.6.6 (and not with other windows binaries nor with other versions of SlikSVN), and only in combination with your server (and not with other (public) https servers).

I don't have time to reproduce or investigate myself, but just some ideas:

- Is there anything that you can think of that makes a difference between your server and google or sourceforge servers? I'm thinking of things like http compression (use of DEFLATE filters in your apache config, and of http-compression in your client-side configuration), and proxy servers (any of those connections going through a proxy, as opposed to the others?). Also, maybe you're accessing your own server through another (internal) network route than google or sourceforge? Maybe there's a difference in proxies, firewalls, ...?

- Any specific configuration in your client-side "servers" configuration file?

- Can you also reproduce this on a 32-bit Windows system?

- Are you using neon or serf for any of those connections (default in 1.6.x is still neon, I believe, but you can configure serf in your "servers" file, or by command line option)?

- Since it only happens with SlikSVN 1.6.6, and not with the tigris.org 1.6.6 svn client, it must have something to do with differences in how they were built (both clients do pick up the same client-side config, don't they?). Dependencies on other libraries come to mind: maybe they were built against a different version of neon, serf, zlib, apr-util, ... ? I don't know how you can check that, maybe you'll have to ask the people who made those binaries ...

- There might also be other slight differences in the way SlikSVN is built as opposed to the tigris.org client. Maybe they use another compiler version, another Microsoft SDK, other compiler options, ... but that's very difficult to investigate (there can be lots of such small differences).

If all else fails, I think you'll have to try and troubleshoot this with some low-level Windows tools, things like sysinternals (http://technet.microsoft.com/en-us/sysinternals/default.aspx), and the like ... but then you may be in for a long ride.

HTH
Regards,
Johan

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Received on 2009-12-02 11:21:00 CET