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Type:
Bug
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Resolution: Done
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Priority:
Major - P3
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None
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Affects Version/s: None
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Component/s: None
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Labels:
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Sharding NYC
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Fully Compatible
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ALL
Initial state
[direct: mongos] test> sh.status()
shardingVersion
{ _id: 1, clusterId: ObjectId("6407feaf46705024b23e5f69") }
---
shards
[
{
_id: 'config',
host: 'csshard/localhost:27019',
state: 1,
topologyTime: Timestamp({ t: 1678245624, i: 1 })
},
{
_id: 'shard2',
host: 'shard2/localhost:27021',
state: 1,
topologyTime: Timestamp({ t: 1678245703, i: 2 })
}
]
---
active mongoses
[ { '7.0.0-alpha-538-g7cec1b7': 1 } ]
---
autosplit
{ 'Currently enabled': 'yes' }
---
balancer
{ 'Currently enabled': 'yes', 'Currently running': 'no' }
---
databases
[
{
database: { _id: 'config', primary: 'config', partitioned: true },
collections: {
'config.system.sessions': {
shardKey: { _id: 1 },
unique: false,
balancing: true,
chunkMetadata: [ { shard: 'config', nChunks: 1024 } ],
chunks: [
'too many chunks to print, use verbose if you want to force print'
],
tags: []
}
}
},
{
database: {
_id: 'test',
primary: 'shard2',
partitioned: false,
version: {
uuid: UUID("5ed830ec-10da-42f9-b92a-b7e3f78df969"),
timestamp: Timestamp({ t: 1678245720, i: 1 }),
lastMod: 1
}
},
collections: {
'test.bar': {
shardKey: { a: 1 },
unique: true,
balancing: true,
chunkMetadata: [ { shard: 'shard2', nChunks: 1 } ],
chunks: [
{ min: { a: MinKey() }, max: { a: MaxKey() }, 'on shard': 'shard2', 'last modified': Timestamp({ t: 1, i: 0 }) }
],
tags: []
},
'test.baz': {
shardKey: { a: 1 },
unique: true,
balancing: true,
chunkMetadata: [ { shard: 'shard2', nChunks: 1 } ],
chunks: [
{ min: { a: MinKey() }, max: { a: MaxKey() }, 'on shard': 'shard2', 'last modified': Timestamp({ t: 1, i: 0 }) }
],
tags: []
},
'test.shards': {
shardKey: { a: 1 },
unique: false,
balancing: true,
chunkMetadata: [ { shard: 'config', nChunks: 1 } ],
chunks: [
{ min: { a: MinKey() }, max: { a: MaxKey() }, 'on shard': 'config', 'last modified': Timestamp({ t: 1, i: 4 }) }
],
tags: []
}
}
}
]
Start to end removal
[direct: mongos] test> db.adminCommand({removeShard: "config"})
{
msg: 'draining started successfully',
state: 'started',
shard: 'config',
note: 'you need to drop or movePrimary these databases',
dbsToMove: [],
ok: 1,
'$clusterTime': {
clusterTime: Timestamp({ t: 1678337082, i: 3 }),
signature: {
hash: Binary(Buffer.from("0000000000000000000000000000000000000000", "hex"), 0),
keyId: Long("0")
}
},
operationTime: Timestamp({ t: 1678337082, i: 3 })
}
[direct: mongos] test> db.adminCommand({removeShard: "config"})
{
msg: 'removeshard completed successfully',
state: 'completed',
shard: 'config',
ok: 1,
'$clusterTime': {
clusterTime: Timestamp({ t: 1678338347, i: 4 }),
signature: {
hash: Binary(Buffer.from("0000000000000000000000000000000000000000", "hex"), 0),
keyId: Long("0")
}
},
operationTime: Timestamp({ t: 1678338347, i: 4 })
}
End state:
[direct: mongos] test> sh.status()
shardingVersion
{ _id: 1, clusterId: ObjectId("6407feaf46705024b23e5f69") }
---
shards
[
{
_id: 'shard2',
host: 'shard2/localhost:27021',
state: 1,
topologyTime: Timestamp({ t: 1678338347, i: 1 })
}
]
---
active mongoses
[ { '7.0.0-alpha-538-g7cec1b7': 1 } ]
---
autosplit
{ 'Currently enabled': 'yes' }
---
balancer
{ 'Currently enabled': 'yes', 'Currently running': 'no' }
---
databases
[
{
database: { _id: 'config', primary: 'config', partitioned: true },
collections: {
'config.system.sessions': {
shardKey: { _id: 1 },
unique: false,
balancing: true,
chunkMetadata: [ { shard: 'shard2', nChunks: 1024 } ],
chunks: [
'too many chunks to print, use verbose if you want to force print'
],
tags: []
}
}
},
{
database: {
_id: 'test',
primary: 'shard2',
partitioned: false,
version: {
uuid: UUID("5ed830ec-10da-42f9-b92a-b7e3f78df969"),
timestamp: Timestamp({ t: 1678245720, i: 1 }),
lastMod: 1
}
},
collections: {
'test.bar': {
shardKey: { a: 1 },
unique: true,
balancing: true,
chunkMetadata: [ { shard: 'shard2', nChunks: 1 } ],
chunks: [
{ min: { a: MinKey() }, max: { a: MaxKey() }, 'on shard': 'shard2', 'last modified': Timestamp({ t: 1, i: 0 }) }
],
tags: []
},
'test.baz': {
shardKey: { a: 1 },
unique: true,
balancing: true,
chunkMetadata: [ { shard: 'shard2', nChunks: 1 } ],
chunks: [
{ min: { a: MinKey() }, max: { a: MaxKey() }, 'on shard': 'shard2', 'last modified': Timestamp({ t: 1, i: 0 }) }
],
tags: []
},
'test.shards': {
shardKey: { a: 1 },
unique: false,
balancing: true,
chunkMetadata: [ { shard: 'shard2', nChunks: 1 } ],
chunks: [
{ min: { a: MinKey() }, max: { a: MaxKey() }, 'on shard': 'shard2', 'last modified': Timestamp({ t: 2, i: 0 }) }
],
tags: []
}
}
}
]
Question 1: Is it valid to do this, and stop here - and now the old config shard can just function as a CSRS?
Trying to readd the catalog shard gives an error
[direct: mongos] test> db.adminCommand({ transitionToCatalogShard: 1 });
MongoServerError: can't add shard 'csshard/localhost:27019' because a local database 'test' exists in another shard2
However, dropping that database on csshard (it's empty anyway, all the data was moved) and then re-running is fine
[direct: mongos] test> db.adminCommand({ transitionToCatalogShard: 1 });
{
ok: 1,
'$clusterTime': {
clusterTime: Timestamp({ t: 1678339266, i: 4 }),
signature: {
hash: Binary(Buffer.from("0000000000000000000000000000000000000000", "hex"), 0),
keyId: Long("0")
}
},
operationTime: Timestamp({ t: 1678339266, i: 3 })
}
Question 2: Is this sequence of events valid to get back to the original state, or is there something else I should be aware of?