On 20/09/2021 20:46, Martynas Jusevičius wrote:
On Mon, Sep 20, 2021 at 3:07 PM Andy Seaborne <[email protected]> wrote:
On 20/09/2021 12:02, Martynas Jusevičius wrote:
Hi,
I see that the default Dockerfile has hardcoded
JAVA_OPTIONS="-Xmx2048m -Xms2048m"
https://github.com/apache/jena/blob/main/jena-fuseki2/jena-fuseki-docker/Dockerfile#L107
https://docs.docker.com/engine/reference/builder/#env
"""
The environment variables set using ENV will persist when a container is
run from the resulting image. You can view the values using docker
inspect, and change them using docker run --env <key>=<value>.
"""
so they are the initial runtime settings.
When the container is run, you can pass in other values with
-e JAVA_OPTIONS="..."
I am aware :) This is more regarding reasonable default values.
Space for a single persistent database is a reasonable default setting.
Would there be any reason why these shouldn't be used with Fuseki
containers and/or made the default in the Dockerfile?
Yes to -XX:+UseContainerSupport
Do all major JVMs now support +UseContainerSupport?
I don't know what a safe default of MaxRAMPercentage would be.
Correct heap size depends usage: about 2G per TDB dataset and leave
space for mmap files; memory datasets are in heap so entiurely data size
dependent.
We have started using these options with Java 11 but they have been
backported some updates of Java 8 as well:
https://dzone.com/articles/best-practices-java-memory-arguments-for-container
We have used MaxRAMPercentage=75 successfully and it seems that 80
also works.
Not for TDB - the common use case.
My AWS go-to guy says his experiments show that the OS
needs around 200MB.
Does JVM support matter if we're only talking about Fuseki's image
where the base image and the JVM version are known?
Flexibility. Others may edit the Dockerfile.
