splitChunk

Definition

splitChunk

An internal administrative command. To split chunks, use the sh.splitFind() and sh.splitAt() functions in the mongo shell.

Warning

Be careful when splitting data in a sharded collection to create new chunks. When you shard a collection that has existing data, MongoDB automatically creates chunks to evenly distribute the collection. To split data effectively in a sharded cluster you must consider the number of documents in a chunk and the average document size to create a uniform chunk size. When chunks have irregular sizes, shards may have an equal number of chunks but have very different data sizes. Avoid creating splits that lead to a collection with differently sized chunks.

Tip

• moveChunk

• sh.moveChunk()

The splitChunk command takes a document with the following fields:

Field	Type	Description
ns	string	The complete namespace of the chunk to split.
keyPattern	document	The shard key.
min	document	The lower bound of the shard key for the chunk to split.
max	document	The upper bound of the shard key for the chunk to split.
from	string	The shard that owns the chunk to split.
splitKeys	document	The split point for the chunk.
shardId	document	The shard.