Hi,

I’m experiencing a very similar issue, but specifically related to xlsx templates and different jsreport versions.

While testing, I noticed a significant performance difference between jsreport 2.11 and jsreport 4.12.

Starting from two clean images (fresh containers with default configuration), the execution time of the same xlsx template is much slower on 4.12 compared to 2.11. In our case this has a very negative impact on heavy customer reports, which are quite large.

With 2.11 the report completes successfully and relatively fast.
With 4.12 the same report often ends up consuming much more memory and eventually the container crashes with:

Worker terminated due to reaching memory limit: JS heap out of memory

In production this becomes problematic because large reports can easily trigger an out-of-memory condition, while the exact same template works without issues on the older version.

The problem is very easy to reproduce using the official Docker images:

docker run -p 5488:5488 jsreport/jsreport:2.11.0
docker run -p 80:5488 jsreport/jsreport:4.12.0

Running the same xlsx template on both instances clearly shows the difference in performance and memory usage.

I’ve prepared a minimal reproducible example starting from a simple Excel template, and I’m attaching a URL with the sample Excel file used for the test.
File excel:
https://docs.google.com/spreadsheets/d/1IKceiO1fEWLTqOKw2tzjdWNuls5In7uN/edit?usp=sharing&ouid=105405265111194914502&rtpof=true&sd=true
export:
https://drive.google.com/file/d/18q2cVxPUBsn75Cd2-nZyu7XsZTMInpZ7/view?usp=sharing

Also on chrome-pdf I have similar difference and a constant increasing of container memory even with the "dedicated-process" strategy.

Thanks!