How to check total required heap for ES 8.8

Elastic Stack Elasticsearch
7

i retested ES Service with heap 3g setting (no setting fielddata.cache.size).
ES returned about fielddata below before stopping. Maybe Fielddata circuit breaker didn't control it.

{
  "nodes": {
    "K6V95L0pR36L-_99LIapdw": {
      "breakers": {
        "fielddata": {
          "limit_size_in_bytes": 1288490188,
          "limit_size": "1.1gb",
          "estimated_size_in_bytes": 2766456144,
          "estimated_size": "2.5gb",
          "overhead": 1.03,
          "tripped": 0
        }
      }
    }
  }
}