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RE: Apparent "svn rm" scaling problem in 1.7.x

From: <michael_rytting_at_agilent.com>
Date: Tue, 1 Nov 2011 11:10:44 -0600

LOL! I love the env variable.

Here is some similar data for a local working copy. These are all run with the env variable set. Again, svn rm is significantly slower than all other operations.

svn rm <file> 0.35s
svn st <file> 0.105s
svn blame 0.041s
svn unlock 0.056s
svn lock 0.053s
svn log 0.036s
svn info 0.014s

-----Original Message-----
From: Stefan Sperling [mailto:stsp_at_elego.de]
Sent: Tuesday, November 01, 2011 11:00 AM
To: RYTTING,MICHAEL (A-ColSprings,ex1)
Cc: users_at_subversion.apache.org
Subject: Re: Apparent "svn rm" scaling problem in 1.7.x

On Tue, Nov 01, 2011 at 10:38:07AM -0600, michael_rytting_at_agilent.com wrote:
> Not much of an improvement. "svn rm dir/*" now takes 2m6s vs 7s for "svn rm dir".

Before the patch, we had:

"svn rm dir/*" 6m15s 1.7.1
"svn rm dir" 8.5s 1.7.1
"svn rm dir/*" 1.14s 1.6.17

So this patch cut about 4 minutes of runtime, which is somwhat significant but definitely not enough. But it's a step in the right direction.

> As a side note, I really think there is fundamentally something wrong of the performance of "svn rm" with large working copies. Here are some example times.
> svn rm <file> 7s
> svn add <file> 0.126s
> svn st <file> 2s
> svn blame <file> 0.2s
> svn lock <file> 0.12s
> svn unlock <file> 0.103s
> svn log <file> 0.089s
> svn revert <file> 0.133s
> svn info <file> 0.074s
> I'm assuming that all these commands are doing some form of sqlite
> database transactions, but the rm transaction, in particular, is very
> slow. Even when using a local working copy, I am seeing large
> discrepancies in the time it takes to run "svn rm" vs most other svn
> commands. It's just since the local working copy is faster overall,
> you are less likely to notice the large discrepancy in performance.

Yes, that looks bad. There might be a linear DB table scan involved in 'svn rm' that becomes noticable on large WCs.
Do you see this difference only on NFS or also on local disk?

How are you measuring the time?
Note that most commands take at least one second because Subversion waits for one second for filesystem timestamps to update after some operations. To cut this deliberate delay out of the equation, do this:
Received on 2011-11-01 18:11:30 CET

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