核心概念与原理

// 创建索引
PUT /products
{
  "settings": {
    "number_of_shards": 3,      // 主分片数(创建后不可修改)
    "number_of_replicas": 1     // 副本数(可动态修改)
  },
  "mappings": {
    "properties": {
      "name": { "type": "text" },
      "price": { "type": "float" },
      "created_at": { "type": "date" }
    }
  }
}

PUT /products/_doc/1
{
  "name": "iPhone 15 Pro",
  "price": 7999,
  "brand": "Apple",
  "tags": ["5G", "A17芯片"],
  "created_at": "2024-09-15"
}

{
  "mappings": {
    "properties": {
      "title": {
        "type": "text",              // 分词索引,支持全文检索
        "analyzer": "ik_max_word",   // 使用IK分词器
        "fields": {
          "keyword": {               // 子字段,不分词
            "type": "keyword"
          }
        }
      },
      "status": {
        "type": "keyword"            // 不分词,精确匹配
      }
    }
  }
}

// text字段:模糊搜索
GET /products/_search
{
  "query": {
    "match": { "title": "手机" }  // 可以匹配"智能手机"、"手机壳"
  }
}

// keyword字段:精确匹配、聚合、排序
GET /products/_search
{
  "query": {
    "term": { "status": "published" }  // 必须完全相等
  },
  "aggs": {
    "by_status": {
      "terms": { "field": "status" }   // 按status聚合
    }
  }
}

// 修改refresh间隔(牺牲实时性,提升写入性能)
PUT /logs/_settings
{
  "index.refresh_interval": "30s"
}

// 批量写入时禁用refresh
PUT /logs/_settings
{
  "index.refresh_interval": "-1"
}

// 手动refresh
POST /logs/_refresh

PUT /logs/_settings
{
  "index.translog.durability": "async",     // 异步刷盘,提升性能
  "index.translog.sync_interval": "5s",    // 每5秒刷盘一次
  "index.translog.flush_threshold_size": "512mb"  // 大小阈值
}

// 同一用户的所有订单在同一分片,提升查询性能
PUT /orders/_doc/order-1?routing=user-123
{
  "user_id": "user-123",
  "product": "iPhone"
}

GET /orders/_search?routing=user-123
{
  "query": {
    "term": { "user_id": "user-123" }
  }
}

// 每个租户的数据在独立分片
PUT /logs/_doc/log-1?routing=tenant-A
{
  "tenant_id": "tenant-A",
  "message": "Error occurred"
}

PUT /orders/_doc/1?wait_for_active_shards=2
{
  "order_id": "12345",
  "amount": 999
}

// 批量导入时
PUT /logs/_settings
{
  "index.refresh_interval": "-1",           // 禁用refresh
  "index.number_of_replicas": 0            // 禁用副本
}

// 导入完成后恢复
PUT /logs/_settings
{
  "index.refresh_interval": "1s",
  "index.number_of_replicas": 1
}
POST /logs/_refresh
POST /logs/_forcemerge?max_num_segments=1

PUT /products
{
  "settings": {
    "number_of_shards": 3,
    "number_of_replicas": 1,
    "refresh_interval": "1s"
  },
  "mappings": {
    "properties": {
      "title": {
        "type": "text",
        "analyzer": "ik_max_word",
        "search_analyzer": "ik_smart",      // 搜索时用粗粒度分词
        "fields": {
          "keyword": { "type": "keyword" }  // 支持精确匹配和聚合
        }
      },
      "price": {
        "type": "scaled_float",             // 比float更节省空间
        "scaling_factor": 100
      },
      "tags": {
        "type": "keyword"                   // 数组自动支持
      },
      "created_at": {
        "type": "date",
        "format": "yyyy-MM-dd HH:mm:ss||epoch_millis"
      },
      "location": {
        "type": "geo_point"                 // 地理位置
      }
    }
  }
}

// 自动创建mapping
PUT /logs/_doc/1
{
  "order_id": "123456"  // 被识别为long,不是keyword!
}

// 后续查询失败
GET /logs/_search
{
  "query": {
    "term": { "order_id": "123456" }  // keyword查询,但字段是long
  }
}

// 方案1:预定义Mapping
PUT /logs
{
  "mappings": {
    "properties": {
      "order_id": { "type": "keyword" }
    }
  }
}

// 方案2:使用Index Template
PUT /_index_template/logs_template
{
  "index_patterns": ["logs-*"],
  "template": {
    "mappings": {
      "properties": {
        "order_id": { "type": "keyword" }
      }
    }
  }
}