Elasticsearch删除索引字段方法总结(附实例代码)

// 1. 创建新索引，定义不含该字段的映射
PUT /new_index
{
  "mappings": {
    "properties": {
      "keep_field1": {"type": "text"},
      "keep_field2": {"type": "keyword"}
      // 不包含要删除的字段
    }
  }
}

// 2. 使用 Reindex API 迁移数据
POST /_reindex
{
  "source": {
    "index": "old_index"
  },
  "dest": {
    "index": "new_index"
  },
  "script": {
    "source": """
      // 可以在这里移除字段或转换数据
      ctx._source.remove("field_to_remove");
    """,
    "lang": "painless"
  }
}

// 3. 删除旧索引，使用别名切换（可选）
POST /_aliases
{
  "actions": [
    {"remove": {"index": "old_index", "alias": "my_index"}},
    {"add": {"index": "new_index", "alias": "my_index"}}
  ]
}

POST /your_index/_update_by_query
{
  "script": {
    "source": "ctx._source.remove('field_to_delete')",
    "lang": "painless"
  },
  "query": {
    "exists": {
      "field": "field_to_delete"
    }
  }
}

// 删除字段的映射定义
PUT /your_index/_mapping
{
  "properties": {
    "field_to_delete": {
      "type": null  // 设置为 null 来删除映射
    }
  }
}

// 创建管道
PUT /_ingest/pipeline/remove-field
{
  "processors": [
    {
      "remove": {
        "field": "field_to_remove"
      }
    }
  ]
}

// 查询时使用
GET /your_index/_search
{
  "pipeline": "remove-field"
}

DELETE /your_index

PUT /your_index
{
  "mappings": {
    "properties": {
      // 新映射，不包含要删除的字段
    }
  }
}

# 1. 使用索引别名，实现零停机
PUT /old_index/_alias/my_index

# 2. 创建新索引
PUT /new_index
{
  "mappings": { ... }
}

# 3. 使用reindex迁移
POST /_reindex?wait_for_completion=false
{
  "source": {"index": "old_index"},
  "dest": {"index": "new_index"},
  "script": {
    "source": "ctx._source.remove('unwanted_field')"
  }
}

# 4. 切换别名
POST /_aliases
{
  "actions": [
    {"remove": {"index": "old_index", "alias": "my_index"}},
    {"add": {"index": "new_index", "alias": "my_index"}}
  ]
}

# 5. 删除旧索引（可选）
DELETE /old_index

# 使用 Elasticdump 迁移数据
elasticdump \
  --input=http://localhost:9200/old_index \
  --output=http://localhost:9200/new_index \
  --type=data \
  --transform='doc._source = Object.keys(doc._source)
    .filter(key => key !== "field_to_remove")
    .reduce((obj, key) => {
      obj[key] = doc._source[key];
      return obj;
    }, {})'