[m2e-dev] Improving m2e performance

[Thomas Reinhardt <thomas@xxxxxxxxxxxxx>]

Hello List!

TLDR:
We have a large maven build (200+ projects) which is very slow to build 
in eclipse. I have built tools and procedures to be able to work with 
only a few projects open comfortably. So this is not a cry for help. I 
want to help improve m2e and I think this might be an interesting use 
case/benchmark.

Long version:
As stated above our whole product consists of over 200 different 
projects. A full maven build (without tests) on my laptop takes about 15 
minutes on the command line ("mvn -DskipTests clean package"). In 
eclipse the build often does not finish at all or needs hours. I can 
speed up things when I open projects in groups and wait for the build to 
finish. Even with that workaround it might take me 2 hours until I have 
opened all projects. This seems very wrong as eclipse should at least 
roughly match the command line build speed.

To be clear: in my normal daily work I don't have to open all projects. 
I only ever do that for complex refactorings and things like that. 
Normal daily performance is no problem.
Having said that: I know from the "all projects open" use case that m2e 
does have some issues and builds projects more than once. It is just not 
noticeable when I only have a dozen projects open.

So: I am offering to do any tests some of you might want to do me, give 
remote access or even send you the code. The last one might need some 
work on my side to remove non-public dependencies, maven plugins etc but 
that should not be a problem.

I did try to cut the problem down to a few single offending projects but 
performance just gradually improved/worsened (depending on your 
viewpoint). So I think it is really down to m2e building projects too 
often. Also, the builds are (in my opinion) not very complex: we do 
generate some code from xsd and there is one in-house built maven plugin 
that generates hibernate code from an xml file. Also, this is a javaee 
product (that ultimately generates an ear file and a standalone client) 
and we use m2e-wtp of course.
Also, I tried to debug m2e myself but I quickly realized that I don't 
know enough of the eclipse build model to make any sense of the code.

This is arguably a complex setup and hard to debug but it might just 
make m2e so much better. Please tell me if there is interest to 
investigate the performance issue.



PS:
For completeness my system specs:
debian 10, 32GB ram, intel core i7-8550U, SSD, eclipse 2021-03
m2e 1.17.2.20210219-1922