Solve the problem that Elasticsearch cannot obtain the maximum value sorted by _id

Recently when I was working on a blockchain browser, I used blockNumber as the document_id of elasticsearch. I needed to do a query operation, so I changed it to mysql query.

SELECT MAX(`_id`) FROM `block`; 

Corresponding query in Kibana

GET /block/_search
{
  "query": {
    "bool": {
      "must": [
        {"match": {
          "transactionHandled": true
        }}
      ]
    }
  },
  
  "sort": [
    {
      "_id": {
        "order": "desc"
      }
    }
  ]
}

The result of the query is always that the document with "_id" as "99" is ranked first, which is obviously not in line with my expectations. By querying the information, we get the following solutions:

The reason is that your IDs are strings, and strings are sorted lexicographically (not numerically), so in the string world 9999 > 1000000.

What you should do is create another numeric field in the document that contains the equivalent number to the ID field and sort by that numeric field.