Updates the shard count of the specified stream to the specified number of shards.
Updating the shard count is an asynchronous operation. Upon receiving the request, Kinesis Data Streams returns immediately and sets the status of the stream to
. After the update is complete, Kinesis Data Streams sets the status of the stream back to
. Depending on the size of the stream, the scaling action could take a few minutes to complete. You can continue to read and write data to your stream while its status is
To update the shard count, Kinesis Data Streams performs splits or merges on individual shards. This can cause short-lived shards to be created, in addition to the final shards. We recommend that you double or halve the shard count, as this results in the fewest number of splits or merges.
This operation has the following default limits. By default, you cannot do the following:
- Scale more than twice per rolling 24-hour period per stream
- Scale up to more than double your current shard count for a stream
- Scale down below half your current shard count for a stream
- Scale up to more than 500 shards in a stream
- Scale a stream with more than 500 shards down unless the result is less than 500 shards
- Scale up to more than the shard limit for your account
For the default limits for an AWS account, see Streams Limits
in the Amazon Kinesis Data Streams Developer Guide
. To request an increase in the call rate limit, the shard limit for this API, or your overall shard limit, use the limits form