ElasticSearch consume a large portion of the server's memory

[herve.be...@gmail.com]

Hello,

I installed DCM4CHE 5.14.0 with docker-compose . Elasticsearch failed often. I must to restart. There are many threads that consume a large portion of the server's memory

I have configure Elastic search with the standard docker-compose.yml with a 

services:
  elasticsearch:
    image: docker.elastic.co/elasticsearch/elasticsearch-oss:6.3.2
    environment:
      ES_JAVA_OPTS: -Xms2g -Xmx2g
      TAKE_FILE_OWNERSHIP: 1
    logging:
      driver: json-file
      options:
        max-size: "10m"

I have  Disable swapping and Ensure sufficient virtual memory for Elasticsearch

My question : 

Why is there so much thread consuming memory for elastic search. How to minimize them so that it does not consume all the memory of my server?