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- sh.shardCollection()
sh.shardCollection()¶
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Definition¶
-
sh.
shardCollection
(namespace, key, unique)¶ Shards a collection using the
key
as a the shard key.sh.shardCollection()
takes the following arguments:Parameter Type Description namespace
string The namespace of the collection to shard. key
document A document that specifies the shard key to use to partition and distribute objects among the shards. A shard key may be one field or multiple fields. A shard key with multiple fields is called a “compound shard key.” unique
Boolean When true, ensures that the underlying index enforces a unique constraint. Hashed shard keys do not support unique constraints. New in version 2.4: Use the form
{field: "hashed"}
to create a hashed shard key. Hashed shard keys may not be compound indexes.
Considerations¶
MongoDB provides no method to deactivate sharding for a collection
after calling shardCollection
. Additionally, after
shardCollection
, you cannot change shard keys or modify
the value of any field used in your shard key index.
Example¶
Given the people
collection in the records
database, the
following command shards the collection by the zipcode
field:
Additional Information¶
shardCollection
for additional options,
Sharding and Sharding Introduction for an
overview of sharding, Deploy a Sharded Cluster for a
tutorial, and Shard Keys for choosing a shard key.