Shulou(Shulou.com)06/01 Report--

1. Documents that have been uniquely indexed by sharding mongos > db.testmongo.ensureIndex ({'age':1,'name':1}, {"unique": 1})

{

"raw": {

"shard1/172.31.32.223:27001172.31.35.47:27001172.31.37.105:27001": {

"createdCollectionAutomatically": false

"numIndexesBefore": 1

"ok": 0

"errmsg": "cannot create unique index over {age: 1.0, name: 1.0} with shard key pattern {_ id: 1.0}"

"code": 67

"codeName": "CannotCreateIndex"

"$gleStats": {

"lastOpTime": {

Ts: Timestamp (1529656402, 42)

"t": NumberLong (6)

}

"electionId": ObjectId ("7fffffff0000000000000006")

}

}

"shard2/172.31.32.223:27002172.31.35.47:27002172.31.37.105:27002": {

"createdCollectionAutomatically": true

"numIndexesBefore": 1

"numIndexesAfter": 2

"ok": 1

"$gleStats": {

"lastOpTime": {

Ts: Timestamp (1529656406, 2)

"t": NumberLong (7)

}

"electionId": ObjectId ("7fffffff0000000000000007")

}

}

"shard3/172.31.32.223:27003172.31.35.47:27003172.31.37.105:27003": {

"createdCollectionAutomatically": true

"numIndexesBefore": 1

"numIndexesAfter": 2

"ok": 1

"$gleStats": {

"lastOpTime": {

Ts: Timestamp (1529656406, 2)

"t": NumberLong (6)

}

"electionId": ObjectId ("7fffffff0000000000000006")

}

}

}

"code": 67

"ok": 0

"errmsg": "{shard1/172.31.32.223:27001172.31.35.47:27001172.31.37.105:27001:\" cannot create unique index over {age: 1.0, name: 1.0} with shard key pattern {_ id: 1.0}\ "}"

}

Mongos > db.testmongo.ensureIndex ({'_ id':1,'age':1,'name':1}, {"unique": 1})

{

"raw": {

"shard1/172.31.32.223:27001172.31.35.47:27001172.31.37.105:27001": {

"createdCollectionAutomatically": false

"numIndexesBefore": 1

"numIndexesAfter": 2

"ok": 1

"$gleStats": {

"lastOpTime": {

Ts: Timestamp (1529656437, 1)

"t": NumberLong (6)

}

"electionId": ObjectId ("7fffffff0000000000000006")

}

}

"shard2/172.31.32.223:27002172.31.35.47:27002172.31.37.105:27002": {

"createdCollectionAutomatically": false

"numIndexesBefore": 2

"numIndexesAfter": 3

"ok": 1

"$gleStats": {

"lastOpTime": {

Ts: Timestamp (1529656437, 1)

"t": NumberLong (7)

}

"electionId": ObjectId ("7fffffff0000000000000007")

}

}

"shard3/172.31.32.223:27003172.31.35.47:27003172.31.37.105:27003": {

"createdCollectionAutomatically": false

"numIndexesBefore": 2

"numIndexesAfter": 3

"ok": 1

"$gleStats": {

"lastOpTime": {

Ts: Timestamp (1529656437, 1)

"t": NumberLong (6)

}

"electionId": ObjectId ("7fffffff0000000000000006")

}

}

}

"ok": 1

}

The prefix of the collection unique index that has been shard must be a sharding key.

two。 Collection that has created a unique index goes to shardmongos > db.testtt.getIndexes ()

[

{

"v": 2

"key": {

"_ id": 1

}

"name": "_ id_"

"ns": "welike_mongo.testtt"

}

{

"v": 2

"unique": true

"key": {

"age": 1

"name": 1

}

"name": "age_1_name_1"

"ns": "welike_mongo.testtt"

}

]

Mongos > sh.shardCollection ("welike_mongo.testtt", {_ id:1})

{

"ok": 0

"errmsg": "can't shard collection 'welike_mongo.testtt' with unique index on {age: 1.0, name: 1.0} and proposed shard key {_ id: 1.0} .Uniqueness can't be maintained unless shard key is a prefix"

}

Mongos > sh.shardCollection ("welike_mongo.testtt", {'name':1})

{

"ok": 0

"errmsg": "can't shard collection 'welike_mongo.testtt' with unique index on {age: 1.0, name: 1.0} and proposed shard key {name: 1.0} .Uniqueness can't be maintained unless shard key is a prefix"

}

Mongos > sh.shardCollection ("welike_mongo.testtt", {'age':1})

{"collectionsharded": "welike_mongo.testtt", "ok": 1} collect to shard that has created a unique index. The shard field must be the prefix of the unique index

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