Elasticsearch "_cat/indices" api update delayed until search?

Question

Elasticsearch (v7.9.2) got an api _cat/indices to show index status, the last change made to docs.count seems not visiable, until a search or another update is made.

Is this behaior for the purpose of performance improvement?

And, is there any way to make it always up to date?

---

@Update - How I obverse this?

I'm using logstash to import data into es. In the browser I have opened http://localhost:9200/_cat/indices?v.

After each import, I refresh the browser page, usually it changes.

After the logstash finish, and I terminate it, the count in the page is less than the count from source db (e.g mysql).

Then I refresh the page again and again, it won't change.

But, as I send a query request in postman to query the es index, then refresh again, the docs.count changed, the total count become the same as in the source db.

So, I'm summarizing following behavior:

• At first, the docs.count do update after each import (aka. insert).
• But, as importing continues for a while, without querying on the index, the page's docs.count stopped updating.
• Then, a query on index will force docs.count update to the correct number.
• After that, the above steps will repeat. It does look like some kind of delay until necessary optimization.

---

And, the index setting from http://localhost:9200/xxx/_settings:
(as requested from comment):

{
  "xxx" : {
    "settings" : {
      "index" : {
        "number_of_shards" : "1",
        "provided_name" : "xxx",
        "creation_date" : "1602844600812",
        "analysis" : {
          "analyzer" : {
            "default_search" : {
              "type" : "ik_max_word"
            },
            "default" : {
              "type" : "ik_max_word"
            }
          }
        },
        "number_of_replicas" : "0",
        "uuid" : "qLFMHhyBQNOOs1u_EcJbBg",
        "version" : {
          "created" : "7090299"
        }
      }
    }
  }
}

Answer 1

same issue on the ES version v7.9.3

from ES official docs:

To get an accurate count of Elasticsearch documents, use the cat count or count APIs

the cat count API is accurate on my ES cluster.

GET _cat/count/log-uwsgi-2021?v

epoch	timestamp	count
1638855942	05:45:42	500

Answer 2

last doc.count will be shown when a refresh occurred. it will refresh periodic base on refresh.interval setting.

from documention: Elasticsearch periodically refreshes indices every second, but only on indices that have received one search request or more in the last 30 seconds.