I've checked the maven core and plugins builds, and they're both running around 30s longer than with 2.0.9, with slightly less memory consumption. Other builds I've tried are running nearer to +15s over 2.0.9.

Granted, these aren't huge builds, but neither are they the 3X time increase over 2.0.9 that others are reporting. Can we live with this performance issue through 2.0.10, and try to find a better way around for 2.0.11?

I know that forked plugins is a slightly marginal priority, but I'm willing to bet that more people are using checkstyle than are experiencing huge build-time increases. Rolling back the change that led to this performance degradation will either reinstate a regression caused in the 2.0.9 release, or - if we attempt to also fix that - reinstate some very buggy behavior WRT build paths during interpolation that has existed in one form or another since 2.0.

IMO we have a couple problems here that are largely design issues:

- project/build state can be changed without limit by plugins

- plugins in forked lifecycles depend on changes from previous plugins being propagated into those forked lifecycles

- build paths are impossible to trace through the interpolation process, so adjusting these interpolation points with new build paths is equally impossible. Even adjusting them to be absolute build paths as opposed to relative ones has proven a very difficult task in the past (this was fixed in 2.0.9, which triggered all of this).

John Casey wrote:
If we had more options WRT parsing POM fragments using the generated modello code, it might be possible to do on-demand interpolation during expression evaluation for plugin instance configuration...though I'm not sure how much that would help.

BTW, I don't know for a fact this is the hot spot causing a 3X performance hit, but it's pretty intensive so I'd say it's a very good educated guess.

-john

John Casey wrote:
The problem is, this was a regression issue, based on real improvements we made to the interpolation code in 2.0.9.

To boot these issues to 2.1, we'd need to find a way to reintroduce buggy handling of build paths into the interpolator.



Brian E. Fox wrote:
I agree it should be right, but a 3x hit in build times isn't acceptable. Given the alternative, I would probably boot those issues to 2.1 where they can be handled correctly. The majority of users probably aren't getting hit by these bugs, so forcing the performance hit on them will appear as a regression, not an improvement.

-----Original Message-----
From: John Casey [mailto:[EMAIL PROTECTED] Sent: Monday, August 04, 2008 10:18 AM
To: Maven Developers List
Subject: Re: Maven 2.0.10-RC5

Brett,

This change was in place long before the javadoc plugin problem of the last RC. The problem happens when forking at times, too, since those forked lifecycles sometimes require alternative target directory, etc. If that information has already been interpolated, changeing target directory and associated paths gets problematic quickly.

The fact that any plugin can change project state at will means that we have to be able to propagate these changes to the next plugin. Dirty flags aren't enough here, since it could be literally anywhere in the Model object hierarchy, in the various collections housed in the project instance, etc.

I'm happy to take a less invasive approach here, *if* we can find a way to make behavior consistent. IMO consistency is much more important than speed. In a perfect world, we'd control the mutability of project and build state more carefully, or even retain a more efficient data tree that we could use to incorporate changes and update build paths, plugin configs, etc. more quickly. The approach I added was geared to fit within the constraints of the current data model.

-john

Brett Porter wrote:
Hey John,

Is it necessary for the project on every execution? I thought this was just for ${reactorProjects} - which could be handled on demand in the PPEE?

It might be worth running the profiler over it too to see if there are any particular hotspots that could improved regardless.

- Brett

On 04/08/2008, at 10:55 PM, John Casey wrote:

This may have to do with some very inefficient code I had to put in to solve MNG-3530. It's doing interpolation of the build section of the POM per-plugin now, and restoring it to the dynamic state just after each plugin executes. This was necessary to allow modifications to the project instance happening during a plugin's execution to be seen in successive plugins.

The execution should be correct now, but unfortunately the design of the system prevented an efficient solution. If you would like to look over the code, it's in the MavenProject.calculateConcreteState(..), MavenProject.restoreDyanmicState(..), PluginManager.executeMojo(..), PluginParameterExpressionEvaluator.evaluate(..), and PluginManager.getReport(..) methods.

I'd love suggestions.

-john

Jörg Schaible wrote:
Hi,
John Casey wrote:
Hi,

Here's your daily dose of Maven 2.0.10! I've fixed the regressions
pointed out in RC4, and added integration tests to guard
against their
reintroduction. The new release candidate can be found here:

http://people.apache.org/~jdcasey/stage/apache-maven/2.0.10-RC
5/org/apache/maven/apache-maven/2.0.10-RC5

The release notes (again):

http://jira.codehaus.org/secure/ReleaseNote.jspa?projectId=105
00&styleName=Html&version=14112

Please try it out and let me know if things go wrong.
Does someone else than me also notice a major performance decrease? If I perform a build for our ~150 artifacts it takes with M2010RC5 ~3h while the same task consumes about 40min with M209. Similar results when generating the Eclipse projects.
- Jörg
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Blog: http://www.ejlife.net/blogs/buildchimp/

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John Casey
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Blog: http://www.ejlife.net/blogs/buildchimp/

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