MergeShards
is called when there is a need to reduce the overall capacity of a stream because of excess capacity that is not being used. You must specify the shard to be merged and the adjacent shard for a stream. For more information about merging shards, see Merge Two Shards in the Amazon Kinesis Streams Developer Guide.
If the stream is in the ACTIVE
state, you can call MergeShards
. If a stream is in the CREATING
, UPDATING
, or DELETING
state, MergeShards
returns a ResourceInUseException
. If the specified stream does not exist, MergeShards
returns a ResourceNotFoundException
.
You can use DescribeStream to check the state of the stream, which is returned in StreamStatus
.
MergeShards
is an asynchronous operation. Upon receiving a MergeShards
request, Amazon Kinesis immediately returns a response and sets the StreamStatus
to UPDATING
. After the operation is completed, Amazon Kinesis sets the StreamStatus
to ACTIVE
. Read and write operations continue to work while the stream is in the UPDATING
state.
You use DescribeStream to determine the shard IDs that are specified in the MergeShards
request.
If you try to operate on too many streams in parallel using CreateStream, DeleteStream, MergeShards
or SplitShard, you will receive a LimitExceededException
.
MergeShards
has limit of 5 transactions per second per account.