Compressing is not working perfectly

Elastic Stack Elasticsearch
1

I want to test the index/_source compression of elastic search.
But I think it is not working perfectly.
Someone knows about the compression?

  • tokenizer : standard

  • index compression : true

  • size of index : 2.78G

  • tokenizer : standard

  • index compression : false(default)

  • size of index : 3.00G

  • tokenizer : standard

  • source compression : true(default)

  • size of index : 3.17G

  • tokenizer : standard

  • source compression : false

  • size of index : 3.01G

  • tokenizer : n-gram(2-5level)

  • index compression : true

  • size of index : 8.01G

  • tokenizer : n-gram(2-5level)

  • index compression : false(default)

  • size of index : 7.99G

please help me...