Elasticsearch（三）：批量操作
语法：
什么是partial update？
PUT /index/type/id，创建文档&替换文档，就是一样的语法
一般对应到应用程序中，每次的执行流程基本是这样的：
（1）应用程序先发起一个get请求，获取到document，展示到前台界面，供用户查看和修改
（2）用户在前台界面修改数据，发送到后台
（3）后台代码，会将用户修改的数据在内存中进行执行，然后封装好修改后的全量数据
（4）然后发送PUT请求，到es中，进行全量替换
（5）es将老的document标记为deleted，然后重新创建一个新的document
partial update
post /index/type/id/_update
{
"doc": {
"要修改的少数几个field即可，不需要全量的数据"
}
}
看起来，好像就比较方便了，每次就传递少数几个发生修改的field即可，不需要将全量的document数据发送过去
UT /test_index/test_type/10
{
"test_field1": "test1",
"test_field2": "test2"
}
POST /test_index/test_type/10/_update
{
"doc": {
"test_field2": "updated test2"
}
}
脚本：
es，其实是有个内置的脚本支持的，可以基于groovy脚本实现各种各样的复杂操作
基于groovy脚本，如何执行partial update
es scripting module，我们会在高手进阶篇去讲解，这里就只是初步讲解一下
PUT /test_index/test_type/11
{
"num": 0,
"tags": []
}
（1）内置脚本
POST /test_index/test_type/11/_update
{
"script" : "ctx._source.num+=1"
}
{
"_index": "test_index",
"_type": "test_type",
"_id": "11",
"_version": 2,
"found": true,
"_source": {
"num": 1,
"tags": []
}
}
（2）外部脚本
ctx._source.tags+=new_tag
POST /test_index/test_type/11/_update
{
"script": {
"lang": "groovy",
"file": "test-add-tags",
"params": {
"new_tag": "tag1"
}
}
}
（3）用脚本删除文档
ctx.op = ctx._source.num == count ? 'delete' : 'none'
POST /test_index/test_type/11/_update
{
"script": {
"lang": "groovy",
"file": "test-delete-document",
"params": {
"count": 1
}
}
}
（4）upsert操作
POST /test_index/test_type/11/_update
{
"doc": {
"num": 1
}
}
{
"error": {
"root_cause": [
{
"type": "document_missing_exception",
"reason": "[test_type][11]: document missing",
"index_uuid": "6m0G7yx7R1KECWWGnfH1sw",
"shard": "4",
"index": "test_index"
}
],
"type": "document_missing_exception",
"reason": "[test_type][11]: document missing",
"index_uuid": "6m0G7yx7R1KECWWGnfH1sw",
"shard": "4",
"index": "test_index"
},
"status": 404
}
如果指定的document不存在，就执行upsert中的初始化操作；如果指定的document存在，就执行doc或者script指定的partial update操作
POST /test_index/test_type/11/_update
{
"script" : "ctx._source.num+=1",
"upsert": {
"num": 0,
"tags": []
}
}
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
{
"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} }
{ "doc" : {"test_field2" : "bulk test1"} }
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。