Optimizing Query Statements

The query statements are optimized in terms of query scope and the number of records to be queried at a time.

1. The query scope is planned based on the actual service requirements. The smaller the query range is, the faster the query is. Large query range may cause low query efficiency, sharp increase of the Elasticsearch cluster resource consumption and even breakdown of the cluster. The _source parameter can be used to control the return field information. Do not obtain large fields.
2. The maximum number of query requests is limited to ensure that the memory is not much occupied by the query memory. The default query request of the Elasticsearch usually returns the first 10 records after sorting, and a maximum of 10,000 records can be read at a time. The from and size parameters are used to control the range of records to be read. This prevents too many records from being read at a time. To query more than 10,000 records at a time, run the scroll command. For details, see Scroll Query.

The following is an example of query in security mode:

curl -XGET --tlsv1.2 --negotiate -k -u : "https://ip:httpport/myindex-001/_search?pretty"  -H 'Content-Type: application/json' -d' 
{
  "from": 0,
  "size": 10,
  "_source": "age",
  "query": {
      "match": {
        "age": "56"
      }
  },
  "sort": [
    {
      "age": {
        "order": "asc"
      }
    }
  ]
}'