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https://issues.apache.org/jira/browse/MNG-6311?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16487007#comment-16487007
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Thomas Nikolay edited comment on MNG-6311 at 5/23/18 10:07 AM:
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Our Company runs in the same problem with very large POM structures and 
imports. This is currently a blocker to migrate from 3.3.9 to 3.5.X.

The same POM with JDK 1.8.0_112

* with MVN 3.3.9 duration = 6 seconds

* with MVN 3.5.2 duration = 107 seconds

I analysed with Yourkit  [^Call-tree-–-All-threads-together.html]


was (Author: tnikolay):
Our Company runs in the same problem with very large POM structures and 
imports. This is currently a blocker to migrate from 3.3.9 to 3.5.X.

I analysed with Yourkit  [^Call-tree-–-All-threads-together.html]

> 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
>            Priority: Major
>              Labels: performance
>         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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