Elasticsearch 7.x : 刷新周期 refresh_interval

末蓝、 2022-10-18 15:53 357阅读 0赞

### 1. 简介 ###

当数据添加到索引后并不能马上被查询到，等到索引刷新后才会被查询到。 `refresh_interval` 配置的刷新间隔。

> refresh\_interval 的默认值是 1s。

**单位：**  
如果是指定的纯数字，单位是毫秒。当 `refresh_interval` 为 `-1` 时，意味着不刷新索引。

*  `ms`: 毫秒
 *  `s`: 秒
 *  `m`: 分钟

当需要大量导入数据到`ES`中，可以将 `refresh_interval` 设置为 `-1` 以加快导入速度。导入结束后，再将 `refresh_interval` 设置为一个正数，例如`1s`或者手动 `refresh` 索引。

**速查：**

将某索引的 `refresh_interval` 设置为 `1分钟`

PUT student/_settings
    { 
        "index" : { 
            "refresh_interval" : "1m"
        }
    }

添加数据时忽略 `refresh_interval` 配置，直接触发刷新索引

POST student/_doc?refresh
    {  "name" : "李四" }

**重置 refresh\_interval**

PUT student/_settings
    { 
        "index" : { 
            "refresh_interval" : null
        }
    }

### 2. 示例： ###

创建索引：

PUT student
    { 
      "mappings" : { 
        "properties" : { 
          "name" : { 
            "type" : "keyword"
          },
          "age" : { 
            "type" : "integer"
          }
        }
      }
    }

设置 `refresh_interval`：

PUT student/_settings
    { 
        "index" : { 
            "refresh_interval" : "1m"
        }
    }

添加数据：

POST student/_doc
    {  "name" : "张三" }

马上查询数据，是查不到的：

# 执行
    GET student/_search
    
    # 结果
    { 
      "took" : 0,
      "timed_out" : false,
      "_shards" : { 
        "total" : 1,
        "successful" : 1,
        "skipped" : 0,
        "failed" : 0
      },
      "hits" : { 
        "total" : { 
          "value" : 0,
          "relation" : "eq"
        },
        "max_score" : null,
        "hits" : [ ]
      }
    }

1分钟后查询数据：

# 执行
    GET student/_search
    
    # 结果
    { 
      "took" : 7,
      "timed_out" : false,
      "_shards" : { 
        "total" : 1,
        "successful" : 1,
        "skipped" : 0,
        "failed" : 0
      },
      "hits" : { 
        "total" : { 
          "value" : 1,
          "relation" : "eq"
        },
        "max_score" : 1.0,
        "hits" : [
          { 
            "_index" : "student",
            "_type" : "_doc",
            "_id" : "5b7bmnEBLucs5EFBg4vB",
            "_score" : 1.0,
            "_source" : { 
              "name" : "张三"
            }
          }
        ]
      }
    }

写入数据时可以指定 `?refresh` 让数据马上写入。

POST student/_doc?refresh
    {  "name" : "李四" }

马上去查，能查到数据：

# 执行
    GET student/_search
    
    # 结果
    { 
      "took" : 4,
      "timed_out" : false,
      "_shards" : { 
        "total" : 1,
        "successful" : 1,
        "skipped" : 0,
        "failed" : 0
      },
      "hits" : { 
        "total" : { 
          "value" : 2,
          "relation" : "eq"
        },
        "max_score" : 1.0,
        "hits" : [
          { 
            "_index" : "student",
            "_type" : "_doc",
            "_id" : "5b7bmnEBLucs5EFBg4vB",
            "_score" : 1.0,
            "_source" : { 
              "name" : "张三"
            }
          },
          { 
            "_index" : "student",
            "_type" : "_doc",
            "_id" : "5r7dmnEBLucs5EFBO4ts",
            "_score" : 1.0,
            "_source" : { 
              "name" : "李四"
            }
          }
        ]
      }
    }