How to Increase Synchrony Heap Allocation in Confluence DC

Summary

Collaborative Editing is a feature that allows multiple people to concurrently edit a single Confluence page or blog post. This feature runs on an engine called Synchrony, which spawns a separated JVM Process from the one Confluence runs with in order to handle its operations.

Synchrony has its own Heap Allocation and System Arguments and sometimes, we may need to increase Synchrony Heap Allocation based on the amount of users running the engine at the same time.

Environment

Confluence DataCenter 7.X and later

Solution

Please, follow the steps outlined below:

1. Stop Confluence.

2. Edit your CONFLUENCE_HOME_INSTALL/bin/setenv.sh file; as follows

   • Search for synchrony.memory.max. If you have this argument already added, just change its value to an appropriate allocation.

   • If you don't have this argument, it means that the default Heap Allocation for Synchrony was applied, which, in this case, is 2GB for versions above 7.10 and 1GB for versions below it.

   • You need to add the parameter to change the Heap Allocation. The example below sets it to 3GB, change the number to allocate as many GB's as you may need to.

     1 CATALINA_OPTS="-Dsynchrony.memory.max=3g ${CATALINA_OPTS}"

3. Start Confluence again

It is possible to set the synchrony.memory.max parameter in either a gigabyte or megabytes.

When setting these values in megabytes, set the value by multiplying the desired memory level by 1024. For example, to set the memory at 3 gigabytes, configure the synchrony.memory.max to 3072m (3 x 1024MB):

For the same example using gigabytes, simply use the following argument:

⚠️ When setting the value in gigabytes, do not use ".5" increments as this will cause the JVM to not start properly.