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https://issues.apache.org/jira/browse/MNG-6311?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16644972#comment-16644972
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Fred Bricon commented on MNG-6311:
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I didn't have the chance to test this in m2e, but the current solution concerns
me. The project builder is a singleton,but we have no control on the cache, as
it's a private field. In the context of Eclipse, this means some model would be
read, cached, but then never evicted if it went stale because of workspace
updates. This also most likely will lead to memory leaks. I reckon this is pure
speculation for now, but all that seems highly plausible.
If the cache were injected in DefaultProjectBuilder instead, then we could
inject an Eclipse workspace-aware cache implementation that'd let us provide a
proper eviction mechanism.
> Maven intolerably slow when import scope used heavily in large project
> ----------------------------------------------------------------------
>
> Key: MNG-6311
> URL: https://issues.apache.org/jira/browse/MNG-6311
> Project: Maven
> Issue Type: Bug
> Components: core, Performance
> Affects Versions: 3.5.0, 3.5.2
> Reporter: David Churcher
> Assignee: Sylwester Lachiewicz
> Priority: Major
> Labels: performance
> Fix For: 3.6.0
>
> Attachments: Call-tree-–-All-threads-together.html,
> anon-hierarchy-maven-output.zip, modelcachefix.diff
>
>
> I have a build performance problem that is identical to MNG-5312, and has
> appeared since MNG-6030 in Maven v3.5.0 reversed the patch for MNG-5312,
> removing the ModelCache from some of the overloads for
> DefaultProjectBuilder.build.
> As in MNG-5312 the problem is in a large proprietary project. It uses up to 8
> levels of parent POMs, many of which use the import scope and have large
> dependency-management sections, and has hundreds of dependencies that also
> use the same parent POM hierarchy. Adding some logging shows that Maven does
> over 800,000 uncached reads of parent POM files, which takes about half an
> hour. With model caching this goes down to a few seconds.
> I've attached a patch that fixes this by using a class-level ModelCache in
> DefaultProjectBuilder. This does not suffer from the memory usage problems
> reported in MNG-6030.
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