moveRange

項目一覧

定義
互換性
構文
コマンドフィールド
Considerations
例

定義

moveRange: バージョン 6.0 で追加。
Moves ranges between shards. Run the moveRange command with a mongos instance while using the 管理データベース.

互換性

このコマンドは、次の環境でホストされている配置で使用できます。

MongoDB Atlas はクラウドでの MongoDB 配置のためのフルマネージドサービスです

注意

このコマンドは、すべての MongoDB Atlas クラスターでサポートされています。すべてのコマンドに対する Atlas のサポートについては、「サポートされていないコマンド」を参照してください。

MongoDB Enterprise: サブスクリプションベースの自己管理型 MongoDB バージョン
MongoDB Community: ソースが利用可能で、無料で使用できる自己管理型の MongoDB のバージョン

構文

このコマンドの構文は、次のとおりです。

db.adminCommand(
  {
    moveRange: <namespace>,
    toShard: <ID of the recipient shard>,
    min: <min key of the range to move>, // conditional
    max: <max key of the range to move>, // conditional
    forceJumbo: <bool>, // optional
    writeConcern: <write concern>, // optional
    secondaryThrottle: <bool> // optional
  }
)

コマンドフィールド

このコマンドは、次のフィールドを使用します。

フィールド	タイプ	説明
`toShard`	string	受信者シャードの ID。
`min`	キー	Minimum key of the range to move. Required if you don't specify `max`. If you do not specify `min`, given a chunk `C` where `max` is either the exclusive upper bound of `C` or `C` includes the shard key `max`, `min` is determined in the following way: If the data size of the range between `min(C)` and `max` is less than the per-collection chunk size or the default chunk size, the chunk's `min` value is selected as `min` = `min(C)`. Otherwise, key `min` > `min(C)` where `min` depends on the configured chunk size.
`max`	キー	Maximum key of the range to move. Required if you don't specify `min`. If you do not specify `max`, given a chunk `C` including the shard key `min`, `max` is determined in the following way: If the data size of the range between `min` and `max(C)` is less than the per-collection chunk size or the default chunk size, the chunk's max is selected as `max` = `max(C)`. Otherwise, key `max` < `max(C)` where `max` depends on the configured chunk size.
forceJumbo	ブール値	任意。 Flag that determines if the command can move a range that is too large to migrate. The range may or may not be labeled as jumbo. If `true`, the command can move the range. If `false`, the command cannot move the range. デフォルトは `false` です。警告: The `moveRange` command with `forceJumbo=true` blocks write operations on the collection. This option causes the shard to migrate chunks even when they are larger than the configured chunk size. The collection remains unavailable for writes for the duration of the migration. To migrate these large chunks without this long blocking period, see Balance Ranges that Exceed Size Limit instead.
`writeConcern`	ドキュメント	任意。 Document with the 書込み保証 (write concern). The default is `w: majority`.
`secondaryThrottle`	ブール値	任意。 If `true`, each document move during chunk migration propagates to at least one secondary before the balancer proceeds with the next document. This is equivalent to a write concern of `{ w: 2 }`. Use the `writeConcern` option to specify a different write concern. If `false`, the balancer does not wait for replication to a secondary and instead continues with the next document. For more information, see Secondary Throttle.

The range migration section describes how ranges move between shards on MongoDB.

Considerations

Only use the moveRange in scenarios like:

an initial ingestion of data
a large bulk import operation

Allow the balancer to create and balance ranges in sharded clusters in most cases.

Tip

以下も参照してください。

Create Ranges in a Sharded Cluster

例

The following examples use a collection with:

Shard key x
Configured chunk size of 128MB
A chunk with boundaries: [x: 0, x: 100)

Specify both `min` and `max`

The following table lists the results of setting min and max to various values:

`min`	`max`	結果
`0`	`100`	Moves all the documents in the range to the recipient shard.
`10`	`30`	Creates three sub-ranges: `[x: 0, x: 10)` `[x: 10, x: 30)` `[x: 30, x: 100)` Moves all the documents in `[x: 10, x: 30)` to the recipient shard.
`0`	`20`	Creates two sub-ranges: `[x: 0, x: 20)` `[x: 20, x: 100)` Moves all the documents in `[x: 0, x: 20)` to the recipient shard.
`40`	`100`	Creates two sub-ranges: `[x: 0, x: 40)` `[x: 40, x: 100)` Moves all the documents in `[x: 40, x: 100)` to the recipient shard.

Specify `min` but not `max`

The following table lists the results of setting min to various values:

`min`	Amount of Data in Key Range	結果
`0`	Less than 128 MB contained between keys `x: 0` and `x: 100`.	Moves all the documents in the range to the recipient shard.
`10`	Less than 128 MB contained between keys `x: 0` and `x: 100`.	Creates two sub-ranges: `[x: 0, x: 10)` `[x : 10, x: 100)` Moves all documents in `[x: 10, x: 100)` to the recipient shard.
`10`	128 MB contained between keys `x: 10` and `x: 30`.	Creates three sub-ranges: `[x: 0, x: 10)` `[x: 10, x: 30)` `[x: 30, x: 100)` Moves all documents in `[x: 10, x: 30)` to the recipient shard.

Specify `max` but not `min`

The following table lists the results of setting max to various values:

`max`	Amount of Data in Key Range	結果
`100`	Less than 128 MB contained between keys `x: 0` and `x: 100`.	Moves all the documents in the range to the recipient shard.
`10`	Less than 128 MB contained between keys `x: 0` and `x: 100`.	Creates two sub-ranges: `[x: 0, x: 10)` `[x : 10, x: 100)` Moves all documents in `[x: 0, x: 10)` to the recipient shard.
`30`	128 MB contained between keys `x: 10` and `x: 30`.	Creates three sub-ranges: `[x: 0, x: 10)` `[x: 10, x: 30)` `[x: 30, x: 100)` Moves all documents in `[x: 10, x: 30)` to the recipient shard.

戻る

movePrimary

mergeChunks