reshardCollection Event
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Summary
reshardCollection
New in version 6.1: (Also available in 6.0.14)
A
reshardCollection
event occurs when:The shard key for a collection and the distribution of your data is changed, and
The change stream has showExpandedEvents set to
true
.
Description
Field | Type | Description | |||
---|---|---|---|---|---|
_id | Document | A BSON object which serves as an identifier for the
change stream event. This value is used as the
The For an example of resuming a change stream by | |||
clusterTime | Timestamp |
Due to oplog size limits,
multi-document transactions may create multiple
oplog entries. In a transaction, change stream events staged in a given oplog
entry share the same Events with the same To identify events for a single transaction, you can use the
combination of Changed in version 8.0. | |||
collectionUUID | UUID | UUID identifying the collection where the change occurred. New in version 6.0. | |||
ns | Document | The namespace (database and or collection) affected by the event. | |||
ns.coll | String | The name of the collection where the event occurred. | |||
ns.db | String | The name of the database where the event occurred. | |||
operationDescription | Document | Additional information on the change operation. This document and its subfields only appears when the change stream uses expanded events. New in version 6.0. | |||
operationDescription. reshardUUID | UUID | UUID that identifies the resharding operation. New in version 6.1. | |||
operationDescription.
| shardKey | Document | The shard key for the collection where the change occurred. New in version 6.0. | |||
operationDescription.
| oldShardKey | Document | The shard key for the collection that changed. New in version 6.1. | |||
operationDescription.
| unique | Boolean | This has a value of true if the collection was sharded with a unique shard key. New in version 6.0. | |||
operationDescription.
| numInitialChunks | NumberLong | Number of chunks created on each shard during a New in version 6.0. | |||
operationDescription. collation | Document | Collation document used for the shard key index. New in version 6.1. | |||
operationDescription. zones | Array | The zones added for the new shard key. New in version 6.1. |
Example
The following example shows a reshardCollection
event:
{ "_id": { <ResumeToken> }, "operationType": "reshardCollection", "collectionUUID": 0, "ns": {"db": "reshard_collection_event", "coll": "coll"}, "operationDescription": { "reshardUUID": 0, "shardKey": {"newKey": 1}, "oldShardKey": {"_id": 1}, "unique": false, "numInitialChunks": NumberLong(1), "collation": {"locale": "simple"}, "zones": [ {"zone": "zone1", "min": {"newKey": {"$minKey": 1}}, "max": {"newKey": {"$maxKey": 1}}} ] } }