Hello Johannes,

On your production instance, have you experimented with the maximum heap size (-Xmx) and initial heap size (-Xms) options? The delays you're seeing could be caused by garbage collection pauses, either because too much memory is allocated so GC takes a long time, or because too little is allocated so GC runs often to free up more.

It could be happening only in production because your options are different between the two machines, or simply because production is being actively used by many people, so memory gets used up and needs to be cleaned out more often.

Disclaimer: I'm not a Java developer, so my understanding is 100% textbook instead of real-life observation. I personally just try a bunch of different numbers until the application works the way I want it to. If I'm completely wrong about this, someone correct me!

-Tamara

On Wed, Nov 23, 2022 at 2:06 AM Johannes Bauer <johannes.bauer@tanner.de> wrote:

Hi all,

we have two Linux server VMs where our BaseX application is running

- Integration
- Production

The used database is about 5 GB including a fulltext index and is
identical on both systems.

The production VM is more potent in all aspects (CPU, RAM, Disk IO, ...).
Dispite all of that we do not get any significantly better performance
in the production system.

On top of that we even have XQuery requests that sporadically take very
long (> 1 minute) that would normally take only less than one second.
Again these long requests only happen in the production environment.

My first assumption was that maybe it is due to additional load on the
server from other sources.
But that was not the case. We have the spikes even when there is no load
at all.

Has anyone similar experiences or any ideas what could be the cause for
this behaviour?

Best Regards
Johannes