sh.moveChunk()¶

Definition定义¶

sh.moveChunk(namespace, query, destination)¶

Moves the chunk that contains the document specified by the query to the destination shard. sh.moveChunk() provides a wrapper around the moveChunk database command.

Important

In most circumstances, allow the balancer to automatically migrate chunks, and avoid calling sh.moveChunk() directly.

sh.moveChunk() takes the following arguments:

Parameter参数	Type类型	Description描述
namespace	string	The namespace of the sharded collection that contains the chunk to migrate.
query	document	An equality match on the shard key that selects the chunk to move.
destination	string	The name of the shard to move.

By default, MongoDB cannot move a chunk if the number of documents in the chunk is greater than 1.3 times the result of dividing the configured chunk size by the average document size. Starting in MongoDB 4.4, the moveChunk command can specify a new option forceJumbo to allow for the manual migration of chunks too large to move, with or without the jumbo label. See moveChunk command for details.

Example示例¶

Given the people collection in the records database, the following operation finds the chunk that contains the documents with the zipcode field set to 53187 and then moves that chunk to the shard named shard0019:

sh.moveChunk("records.people", { zipcode: "53187" }, "shard0019")