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David Churcher commented on MNG-6311: ------------------------------------- It's a bit tricky to share more details as we don't own the source for most of it, and a lot of the project hierarchy is inside dependencies that we don't have any source for. I've attached some anonymised output of the hierarchy-maven-plugin - [https://github.com/ExampleDriven/hierarchy-maven-plugin|https://github.com/ExampleDriven/hierarchy-maven-plugin)] - which should give some idea of the scope of the parent POM problem. I will try to script the creation of a similar project. Interestingly when I build the whole project from top down I don't get the performance problem, it is only when I build the integration test project (as in the above hierarchy file) that has low-level dependencies and has to work its way up the dependency tree. > 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: 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. -- This message was sent by Atlassian JIRA (v7.6.3#76005)