ElasticSearch（十一）批量CURD bulk

1、bulk语法

POST /_bulk
{ "delete": { "_index": "test_index", "_type": "test_type", "_id": "3" }} 
{ "create": { "_index": "test_index", "_type": "test_type", "_id": "12" }}
{ "test_field":    "test12" }
{ "index":  { "_index": "test_index", "_type": "test_type", "_id": "2" }}
{ "test_field":    "replaced test2" }
{ "update": { "_index": "test_index", "_type": "test_type", "_id": "1", "_retry_on_conflict" : 3} }
{ "doc" : {"test_field2" : "bulk test1"} }

每一个操作要两个json串，语法如下：

{"action": {"metadata"}}
{"data"}

举例，比如你现在要创建一个文档，放bulk里面，看起来会是这样子的：

{"index": {"_index": "test_index", "_type", "test_type", "_id": "1"}}
{"test_field1": "test1", "test_field2": "test2"}

有哪些类型的操作可以执行呢？
（1）delete：删除一个文档，只要1个json串就可以了
（2）create：PUT /index/type/id/_create，强制创建
（3）index：普通的put操作，可以是创建文档，也可以是全量替换文档
（4）update：执行的partial update操作

bulk api对json的语法，有严格的要求，每个json串不能换行，只能放一行，同时一个json串和一个json串之间，必须有一个换行

如果格式是这样：

POST /_bulk
{"index": 
  {"_index": "test_index", "_type": "test_type","_id": "1"}
  
}
{"test_field1": "test1", "test_field2": "test2"}

结果：

{
  "error": {
    "root_cause": [
      {
        "type": "json_e_o_f_exception",
        "reason": "Unexpected end-of-input within/between Object entries
 at [Source: org.elasticsearch.transport.netty4.ByteBufStreamInput@7da6bde0; line: 1, column: 21]"
      }
    ],
    "type": "json_e_o_f_exception",
    "reason": "Unexpected end-of-input within/between Object entries
 at [Source: org.elasticsearch.transport.netty4.ByteBufStreamInput@7da6bde0; line: 1, column: 21]"
  },
  "status": 500
}

如果格式是这样：

POST /_bulk
{"index": {"_index": "test_index", "_type": "test_type","_id": "1"}}
{"test_field1": "test1", "test_field2": "test2"}

结果：

{
  "took" : 19,
  "errors" : false,
  "items" : [
    {
      "index" : {
        "_index" : "test_index",
        "_type" : "test_type",
        "_id" : "1",
        "_version" : 3,
        "result" : "updated",
        "_shards" : {
          "total" : 2,
          "successful" : 1,
          "failed" : 0
        },
        "_seq_no" : 2,
        "_primary_term" : 5,
        "status" : 200
      }
    }
  ]
}

bulk操作中，任意一个操作失败，是不会影响其他的操作的，但是在返回结果里，会告诉你异常日志

POST /test_index/_bulk
{ "delete": { "_type": "test_type", "_id": "3" }} 
{ "create": { "_type": "test_type", "_id": "12" }}
{ "test_field":    "test12" }
{ "index":  { "_type": "test_type" }}
{ "test_field":    "auto-generate id test" }
{ "index":  { "_type": "test_type", "_id": "2" }}
{ "test_field":    "replaced test2" }
{ "update": { "_type": "test_type", "_id": "1", "_retry_on_conflict" : 3} }
{ "doc" : {"test_field2" : "bulk test1"} }

#! Deprecation: Deprecated field [_retry_on_conflict] used, expected [retry_on_conflict] instead
{
  "took" : 64,
  "errors" : true,
  "items" : [
    {
      "delete" : {
        "_index" : "test_index",
        "_type" : "test_type",
        "_id" : "3",
        "_version" : 1,
        "result" : "not_found",
        "_shards" : {
          "total" : 2,
          "successful" : 1,
          "failed" : 0
        },
        "_seq_no" : 4,
        "_primary_term" : 5,
        "status" : 404
      }
    },
    {
      "create" : {
        "_index" : "test_index",
        "_type" : "test_type",
        "_id" : "12",
        "status" : 409,
        "error" : {
          "type" : "version_conflict_engine_exception",
          "reason" : "[test_type][12]: version conflict, document already exists (current version [2])",
          "index_uuid" : "P8_8FJpGSgW8HglInNvZYQ",
          "shard" : "1",
          "index" : "test_index"
        }
      }
    },
    {
      "index" : {
        "_index" : "test_index",
        "_type" : "test_type",
        "_id" : "Baq9WWgBjIP9BXE3vrJ2",
        "_version" : 1,
        "result" : "created",
        "_shards" : {
          "total" : 2,
          "successful" : 1,
          "failed" : 0
        },
        "_seq_no" : 3,
        "_primary_term" : 5,
        "status" : 201
      }
    },
    {
      "index" : {
        "_index" : "test_index",
        "_type" : "test_type",
        "_id" : "2",
        "_version" : 1,
        "result" : "created",
        "_shards" : {
          "total" : 2,
          "successful" : 1,
          "failed" : 0
        },
        "_seq_no" : 4,
        "_primary_term" : 5,
        "status" : 201
      }
    },
    {
      "update" : {
        "_index" : "test_index",
        "_type" : "test_type",
        "_id" : "1",
        "_version" : 4,
        "result" : "updated",
        "_shards" : {
          "total" : 2,
          "successful" : 1,
          "failed" : 0
        },
        "_seq_no" : 4,
        "_primary_term" : 5,
        "status" : 200
      }
    }
  ]
}

同一个index和type的情况下：

POST /test_index/test_type/_bulk
{ "delete": { "_id": "3" }} 
{ "create": { "_id": "12" }}
{ "test_field":    "test12" }
{ "index":  { }}
{ "test_field":    "auto-generate id test" }
{ "index":  { "_id": "2" }}
{ "test_field":    "replaced test2" }
{ "update": { "_id": "1", "_retry_on_conflict" : 3} }
{ "doc" : {"test_field2" : "bulk test1"} }

2、bulk size最佳大小

bulk request会加载到内存里，如果太大的话，性能反而会下降，因此需要反复尝试一个最佳的bulk size。一般从1000~5000条数据开始，尝试逐渐增加。另外，如果看大小的话，最好是在5~15MB之间。