I have a Maven build job setup in Jenkins, with following notable configs :
- It is a multi-module job with 75 modules
- It is built incrementally (build only changed modules)
- Automatic artifact archiving is disabled
The build time is approx 20 mins. However, from some time the build time has drastically increased to 1 hr 15 mins. The job is still building incrementally and the current build number is about 1450. I am preserving only 3 old builds. My question is why there is such high increment in build times ?
Here are the things I have tried and observed :
Maven job creates fingerprints by default. With large number of builds (currently 1450) there may be huge fingerprint data which is being accessed during building and hence is adding to the overall build time. However, I cleaned up all the existing fingerprints and tried rebuilding the project. This had no impact on the build time (still took 1 hr to complete).
I tried doing a full build, instead of an incremental build to know if major time is being spent in identifying the modules to be build. This also did not help and the full build completed in 1 hr 20 mins.
I also tried building the job on a dedicated slave, in case the problem was due to resource availability. This had no impact on build times.
The only thing that worked was renaming the job itself. After renaming build are completing again in approx 20 mins. But I am not sure if this is an ideal solution. Also I don't understand the logic behind this approach of renaming the job.
Could someone suggest as to what is happening inside Maven build to increase the build times after a large number of builds ? I am using Jenkins v1.560 and maven project plugin v2.0. Upgrading Maven plugin or Jenkins is not an option for me now.
Update 1
As per analysis of build outputs, major build time is being spent in "Parsing POMs" (approx 30 mins) and "Metadata collection" step (approx 20 mins). Does anyone have any idea as to what exactly happens during these 2 steps ?