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sh.balancerCollectionStatus()

sh.balancerCollectionStatus(namespace)

Returns a document that contains information about whether the chunks of a sharded collection are balanced (i.e. do not need to be moved) as of the time the command is run or need to be moved because of draining shards, zone violation or imbalance of chunks across shards.

重要

mongosh 方法

本页面提供 mongosh 方法的相关信息。这不是数据库命令或特定语言驱动程序(例如 Node.js)的相关文档。

有关数据库命令,请参阅 balancerCollectionStatus 命令。

如需了解 MongoDB API 驱动程序,请参阅特定语言的 MongoDB 驱动程序文档。

This method is available in deployments hosted in the following environments:

  • MongoDB Atlas: The fully managed service for MongoDB deployments in the cloud

重要

This command is not supported in M0, M2, and M5 clusters. For more information, see Unsupported Commands.

The sh.balancerCollectionStatus() has the following form:

sh.balancerCollectionStatus( <namespace> )

The sh.balancerCollectionStatus() method takes the following parameter:

Parameter
类型
说明

String

The namespace of the collection to shard in the form "<database>.<collection>".

When running with access control, the user must have the enableSharding privilege actions on database and/or collection to run the method. That is, a user must have a role that grants the following privilege:

{ resource: { db: <database>, collection: <collection> }, actions: [ "enableSharding" ] }

The built-in clusterManager role provides the appropriate privileges.

To check whether the chunks of a sharded collection test.contacts is currently in balance, connect to a mongos instance and issue the following:

sh.balancerCollectionStatus("test.contacts")

If the chunks for the collection do not need to be moved, the method returns an output similar to the following:

{
"balancerCompliant" : true,
"ok" : 1,
"operationTime" : Timestamp(1583193238, 1),
"$clusterTime" : {
"clusterTime" : Timestamp(1583193238, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
}
}

If the queried namespace is going through chunk defragmentation, the sh.balancerCollectionStatus method returns output similar to the following:

{
"chunkSize": Long("128"),
"balancerCompliant": false,
"firstComplianceViolation": "defragmentingChunks",
"details": {
"currentPhase": "moveAndMergeChunks",
"progress": { "remainingChunksToProcess": 1 }
}
}

注意

Chunk defragmentation occurs in multiple phases. The progress field only pertains to the current phase.

For the description of the output, see balancerCollectionStatus Output.