【Mongo】mongos shard 唯一索引的问题

1.已经被sharding的文档建立唯一索引

1. mongos> db.testmongo.ensureIndex({'age':1,'name':1},{"unique":1})
   
2. {
   
3. "raw" : {
   
4. "shard1/172.31.32.223:27001,172.31.35.47:27001,172.31.37.105:27001" : {
   
5. "createdCollectionAutomatically" : false,
   
6. "numIndexesBefore" : 1,
   
7. "ok" : 0,
   
8. "errmsg" : "cannot create unique index over { age: 1.0, name: 1.0 } with shard key pattern { _id: 1.0 }",
   
9. "code" : 67,
   
10. "codeName" : "CannotCreateIndex",
    
11. "$gleStats" : {
    
12. "lastOpTime" : {
    
13. "ts" : Timestamp(1529656402, 42),
    
14. "t" : NumberLong(6)
    
15. },
    
16. "electionId" : ObjectId("7fffffff0000000000000006")
    
17. }
    
18. },
    
19. "shard2/172.31.32.223:27002,172.31.35.47:27002,172.31.37.105:27002" : {
    
20. "createdCollectionAutomatically" : true,
    
21. "numIndexesBefore" : 1,
    
22. "numIndexesAfter" : 2,
    
23. "ok" : 1,
    
24. "$gleStats" : {
    
25. "lastOpTime" : {
    
26. "ts" : Timestamp(1529656406, 2),
    
27. "t" : NumberLong(7)
    
28. },
    
29. "electionId" : ObjectId("7fffffff0000000000000007")
    
30. }
    
31. },
    
32. "shard3/172.31.32.223:27003,172.31.35.47:27003,172.31.37.105:27003" : {
    
33. "createdCollectionAutomatically" : true,
    
34. "numIndexesBefore" : 1,
    
35. "numIndexesAfter" : 2,
    
36. "ok" : 1,
    
37. "$gleStats" : {
    
38. "lastOpTime" : {
    
39. "ts" : Timestamp(1529656406, 2),
    
40. "t" : NumberLong(6)
    
41. },
    
42. "electionId" : ObjectId("7fffffff0000000000000006")
    
43. }
    
44. }
    
45. },
    
46. "code" : 67,
    
47. "ok" : 0,
    
48. "errmsg" : "{ shard1/172.31.32.223:27001,172.31.35.47:27001,172.31.37.105:27001: \"cannot create unique index over { age: 1.0, name: 1.0 } with shard key pattern { _id: 1.0 }\" }"
    
49. }
    
50. mongos> db.testmongo.ensureIndex({'_id':1,'age':1,'name':1},{"unique":1})
    
51. {
    
52. "raw" : {
    
53. "shard1/172.31.32.223:27001,172.31.35.47:27001,172.31.37.105:27001" : {
    
54. "createdCollectionAutomatically" : false,
    
55. "numIndexesBefore" : 1,
    
56. "numIndexesAfter" : 2,
    
57. "ok" : 1,
    
58. "$gleStats" : {
    
59. "lastOpTime" : {
    
60. "ts" : Timestamp(1529656437, 1),
    
61. "t" : NumberLong(6)
    
62. },
    
63. "electionId" : ObjectId("7fffffff0000000000000006")
    
64. }
    
65. },
    
66. "shard2/172.31.32.223:27002,172.31.35.47:27002,172.31.37.105:27002" : {
    
67. "createdCollectionAutomatically" : false,
    
68. "numIndexesBefore" : 2,
    
69. "numIndexesAfter" : 3,
    
70. "ok" : 1,
    
71. "$gleStats" : {
    
72. "lastOpTime" : {
    
73. "ts" : Timestamp(1529656437, 1),
    
74. "t" : NumberLong(7)
    
75. },
    
76. "electionId" : ObjectId("7fffffff0000000000000007")
    
77. }
    
78. },
    
79. "shard3/172.31.32.223:27003,172.31.35.47:27003,172.31.37.105:27003" : {
    
80. "createdCollectionAutomatically" : false,
    
81. "numIndexesBefore" : 2,
    
82. "numIndexesAfter" : 3,
    
83. "ok" : 1,
    
84. "$gleStats" : {
    
85. "lastOpTime" : {
    
86. "ts" : Timestamp(1529656437, 1),
    
87. "t" : NumberLong(6)
    
88. },
    
89. "electionId" : ObjectId("7fffffff0000000000000006")
    
90. }
    
91. }
    
92. },
    
93. "ok" : 1
    
94. }

2.已经建立唯一索引的collection去shard

1. mongos> 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"
   }
   ]
   
   
2. mongos> sh.shardCollection("welike_mongo.testtt",{_id:1})
   
3. {
   
4. "ok" : 0,
   
5. "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"
   
6. }
   
7. mongos> sh.shardCollection("welike_mongo.testtt",{'name':1})
   
8. {
   
9. "ok" : 0,
   
10. "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"
    
11. }
    
12. mongos> sh.shardCollection("welike_mongo.testtt",{'age':1})
    
13. { "collectionsharded" : "welike_mongo.testtt", "ok" : 1 }