Elasticsearch reports default heap memory size after setting environment variable

Question

In attempt to increase JVM heap size for Elasticsearch on a Windows box, I defined the following environment variable:

ES_HEAP_SIZE=6g

(The machine has 12G RAM in total).

I have restarted ES and queried its memory usage using _nodes/stat HTTP GET command. However, it seems that it's still using 1GB:

mem: {

heap_used_in_bytes: 1032367576,
heap_used_percent: 99,
heap_committed_in_bytes: 1037959168,
heap_max_in_bytes: 1037959168,
...

Shouldn't ES adjust its heap memory size after the restart?

Answer 1

From the notes on running ES as a service on windows:

Note that the environment configuration options available during the installation are copied and will be used during the service lifecycle. This means any changes made to them after the installation will not be picked up unless the service is reinstalled.

If you don't want to uninstall and re-install, you can use the service manager to make the change. Run >service manager

Then select the 'Java' Tab

Change the memory pool settings, hit 'Apply' and restart the service.