shardCollection
Event
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Summary
Description
Field | Type | Description | |||
---|---|---|---|---|---|
| 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 | |||
| 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 On sharded clusters, events with the same To identify events for a single transaction, you can use the
combination of | |||
| UUID | UUID identifying the collection where the change occurred. New in version 6.0. | |||
| document | The identifier for the session associated with the transaction. Only present if the operation is part of a multi-document transaction. | |||
| document | The namespace (database and or collection) affected by the event. | |||
| string | The name of the collection where the event occurred. | |||
| string | The name of the database where the event occurred. | |||
| 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. numInitialChunks | long | Number of chunks created on each shard during a New in version 6.0. | |||
operationDescription. presplitHashedZones | boolean | Indicates whether the shard chunks were pre-split according to zones when the collection becamed sharded. New in version 6.0. | |||
operationDescription. shardKey | document | The shard key for the collection where the change occurred. New in version 6.0. | |||
operationDescription. unique | boolean | This has a value of true if the collection was sharded with a unique shard key. New in version 6.0. | |||
| string | The type of operation that the change notification reports. Returns a value of | |||
| NumberLong | Together with the lsid, a number that helps uniquely identify a transction. Only present if the operation is part of a multi-document transaction. | |||
| The server date and time of the database operation. New in version 6.0. |
Example
The following example shows a shardCollection
event:
{ "_id": { <ResumeToken> }, "operationType": "shardCollection", "clusterTime": Timestamp({ t: 1654894852, i: 52 }), "collectionUUID": UUID("98046a1a-b649-4e5b-9c75-67594221ce19"), "wallTime": ISODate("2022-06-10T21:00:52.854Z"), "ns": { "db": "test", "coll": "authors" }, "operationDescription": { "shardKey": { "age": "hashed" }, "unique": false, "numInitialChunks": Long("0"), "presplitHashedZones": false } }