27_分布式文档系统_上机动手实战演练bulk批量增删改

课程大纲

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} }

每一个操作要两个json串，语法如下：

{"action": {"metadata"}}

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"}}

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

{
"error": {
"root_cause": [
{
"type": "json_e_o_f_exception",
"reason": "Unexpected end-of-input: expected close marker for Object (start marker at [Source: org.elasticsearch.transport.netty4.ByteBufStreamInput@5a5932cd; line: 1, column: 1])\n at [Source: org.elasticsearch.transport.netty4.ByteBufStreamInput@5a5932cd; line: 1, column: 3]"
}
],
"type": "json_e_o_f_exception",
"reason": "Unexpected end-of-input: expected close marker for Object (start marker at [Source: org.elasticsearch.transport.netty4.ByteBufStreamInput@5a5932cd; line: 1, column: 1])\n at [Source: org.elasticsearch.transport.netty4.ByteBufStreamInput@5a5932cd; line: 1, column: 3]"
},
"status": 500
}

{
"took": 41,
"errors": true,
"items": [
{
"delete": {
"found": true,
"_index": "test_index",
"_type": "test_type",
"_id": "10",
"_version": 3,
"result": "deleted",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"status": 200
}
},
{
"create": {
"_index": "test_index",
"_type": "test_type",
"_id": "3",
"_version": 1,
"result": "created",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"created": true,
"status": 201
}
},
{
"create": {
"_index": "test_index",
"_type": "test_type",
"_id": "2",
"status": 409,
"error": {
"type": "version_conflict_engine_exception",
"reason": "[test_type][2]: version conflict, document already exists (current version [1])",
"index_uuid": "6m0G7yx7R1KECWWGnfH1sw",
"shard": "2",
"index": "test_index"
}
}
},
{
"index": {
"_index": "test_index",
"_type": "test_type",
"_id": "4",
"_version": 1,
"result": "created",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"created": true,
"status": 201
}
},
{
"index": {
"_index": "test_index",
"_type": "test_type",
"_id": "2",
"_version": 2,
"result": "updated",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"created": false,
"status": 200
}
},
{
"update": {
"_index": "test_index",
"_type": "test_type",
"_id": "1",
"_version": 3,
"result": "updated",
"_shards": {
"total": 2,
"successful": 1,
"failed": 0
},
"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} }

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} }

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。