第2课: 核心概念深入解析

# 1. 创建简单索引（使用默认配置）
PUT /products

# 2. 创建带详细配置的索引
PUT /products
{
  "settings": {
    "number_of_shards": 3,        # 主分片数量
    "number_of_replicas": 2,      # 每个主分片的副本数量
    "refresh_interval": "1s",     # 刷新间隔（近实时性）
    "index.max_result_window": 10000  # 最大返回结果数
  },
  "mappings": {
    "properties": {
      "name": { "type": "text" },
      "price": { "type": "float" }
    }
  }
}

# 3. 创建时间序列索引（适合日志数据）
PUT /logs-2024.01.01
{
  "settings": {
    "number_of_shards": 1,
    "number_of_replicas": 1
  }
}

# 1. 自动生成ID（推荐用于日志等场景）
POST /products/_doc
{
  "name": "iPhone 15",
  "price": 5999,
  "category": "手机"
}

# 响应：自动生成ID，如 "_id": "abc123"

# 2. 指定ID（推荐用于业务数据）
PUT /products/_doc/1
{
  "name": "iPhone 15",
  "price": 5999,
  "category": "手机"
}

# 3. 批量操作
POST /_bulk
{ "index": { "_index": "products", "_id": "1" } }
{ "name": "iPhone 15", "price": 5999 }
{ "index": { "_index": "products", "_id": "2" } }
{ "name": "iPad Pro", "price": 7999 }

# 完整的文档示例（包含元数据）
{
  "_index": "products",
  "_id": "1",
  "_version": 1,
  "_seq_no": 0,
  "_primary_term": 1,
  "found": true,
  "_source": {
    "name": "iPhone 15",
    "price": 5999,
    "category": "手机",
    "brand": "Apple",
    "tags": ["智能手机", "苹果"],
    "specifications": {
      "screen": "6.1英寸",
      "memory": "128GB"
    },
    "created_at": "2024-01-01T10:00:00Z"
  }
}

# 错误用法：将需要精确匹配的字段设为text类型
PUT /products
{
  "mappings": {
    "properties": {
      "category": { "type": "text" }  # 错误！category应该用keyword
    }
  }
}

# 正确用法：text用于全文检索，keyword用于精确匹配
PUT /products
{
  "mappings": {
    "properties": {
      "title": { "type": "text" },      # 需要全文检索
      "category": { "type": "keyword" }, # 需要精确匹配
      "description": { 
        "type": "text",
        "fields": {
          "keyword": { "type": "keyword" }  # 多字段：同时支持两种方式
        }
      }
    }
  }
}

# 1. 动态映射：Elasticsearch自动推断类型
PUT /dynamic_index/_doc/1
{
  "title": "Elasticsearch教程",     # 推断为text
  "price": 99.99,                   # 推断为float
  "category": "技术书籍",            # 推断为text（可能不是最佳选择）
  "published": true,                # 推断为boolean
  "publish_date": "2024-01-01"      # 推断为date
}

# 查看自动生成的映射
GET /dynamic_index/_mapping

# 2. 显式映射：手动定义最佳类型
PUT /products
{
  "mappings": {
    "properties": {
      "name": { 
        "type": "text",
        "analyzer": "ik_max_word",  # 使用中文分词器
        "search_analyzer": "ik_smart"
      },
      "price": { 
        "type": "float",
        "index": true               # 可被索引（默认）
      },
      "category": { 
        "type": "keyword",
        "ignore_above": 256         # 超过256字符的keyword不会被索引
      },
      "description": { 
        "type": "text",
        "fields": {
          "keyword": { "type": "keyword" }  # 多字段配置
        }
      },
      "created_at": { 
        "type": "date",
        "format": "yyyy-MM-dd HH:mm:ss||yyyy-MM-dd||epoch_millis"
      },
      "tags": {
        "type": "nested",           # 嵌套类型，保持数组元素独立性
        "properties": {
          "name": { "type": "keyword" },
          "color": { "type": "keyword" }
        }
      }
    }
  }
}

# 查看映射
GET /products/_mapping

# 1. 默认配置（5个主分片，1个副本）
PUT /default_index

# 2. 自定义分片配置
PUT /custom_index
{
  "settings": {
    "number_of_shards": 3,        # 主分片数量
    "number_of_replicas": 2,      # 每个主分片的副本数量
    "routing.allocation.total_shards_per_node": 10  # 每个节点最大分片数
  }
}

# 3. 查看分片分布
GET /_cat/shards?v&s=node

# 4. 查看分片健康状态
GET /_cat/indices?v&health=red,yellow,green