MongoError：复合索引的E11000重复键错误集合（不是唯一的）

Question

1. Nodejs mongodb模块：

**db.collection('pci')    
    .insertOne({bl: 'register',     
    product: 'hlr',     
    branch: 'master',    
    buildid: 'HLRYL190027z'}, (err,pciResult) => {....});** 

1. 错误详细信息：
   MongoError：insertDocument ::由:: 11000 E11000引起的重复键错误索引：pipeline.pci。$ bl_1_product_1_branch_1_buildid_1 dup键：{：“ registers”，：“ hlr”，：“ master”，：“ HLRYL1900271”}
   在Function.MongoError.create（/data/falcon/producer/node_modules/mongodb-core/lib/error.js:31:11）
2. 图片集中的文档

{"_id":"5bbcf2f12f717e8492c3e873",    
    "product":"hlr",     
    "rollback":"NO",    
    "buildresult":"PASS",    
    "buildstart":1539108375,    
    "buildid":"HLRYL1900271",    
    "bl":"registers",    
    "branch":"master"}

1. 图片收藏的索引（没有唯一性）

[
	{
		"v" : 1,
		"key" : {
			"_id" : 1
		},
		"name" : "_id_",
		"ns" : "pipeline.pci"
	},
	{
		"v" : 1,
		"key" : {
			"buildstart" : 1
		},
		"name" : "buildstart_1",
		"ns" : "pipeline.pci"
	},
	{
		"v" : 1,
		"key" : {
			"product" : 1,
			"branch" : 1,
			"type" : 1,
			"buildend" : -1
		},
		"name" : "product_1_branch_1_type_1_buildend_-1",
		"ns" : "pipeline.pci"
	},
	{
		"v" : 1,
		"key" : {
			"buildid" : -1
		},
		"name" : "buildid_-1",
		"ns" : "pipeline.pci"
	},
	{
		"v" : 1,
		"key" : {
			"buildend" : -1
		},
		"name" : "buildend_-1",
		"ns" : "pipeline.pci"
	},
	{
		"v" : 1,
		"key" : {
			"bl" : 1,
			"product" : 1,
			"branch" : 1,
			"buildid" : -1
		},
		"name" : "bl_1_product_1_branch_1_buildid_-1",
		"ns" : "pipeline.pci"
	},
	{
		"v" : 1,
		"key" : {
			"promotion_tags" : -1
		},
		"name" : "promotion_tags_-1",
		"ns" : "pipeline.pci"
	},
	{
		"v" : 1,
		"key" : {
			"product" : 1,
			"branch" : 1,
			"type" : 1,
			"buildstart" : -1
		},
		"name" : "product_1_branch_1_type_1_buildstart_-1",
		"ns" : "pipeline.pci"
	}
]

5.环境
mongodb nodejs模块：“〜2.1.21”，
mongodb：MongoDB外壳程序版本：2.6.11
6.分析
我搜索了很多有关此问题的资源，
但我不知道为什么会引发此错误。
也许并发？但是nodejs是单线程的，因此我尚未为此操作创建新的子进程。
Mongodb的问题？ 索引问题？