Merges two adjacent shards in a Kinesis data stream and combines them into a single shard to reduce the stream's capacity to ingest and transport data. Two shards are considered adjacent if the union of the hash key ranges for the two shards form a contiguous set with no gaps. For example, if you have two shards, one with a hash key range of 276...381 and the other with a hash key range of 382...454, then you could merge these two shards into a single shard that would have a hash key range of 276...454. After the merge, the single child shard receives data for all hash key values covered by the two parent shards.
merge_shards 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 Data Streams Developer Guide.
If the stream is in the ACTIVE state, you can call
merge_shards. If a stream is in the
CREATING, UPDATING, or DELETING state,
merge_shards returns a
ResourceInUseException. If the specified stream does not exist,
merge_shards returns a
ResourceNotFoundException.
You can use describe_stream to check the
state of the stream, which is returned in StreamStatus.
merge_shards is an asynchronous operation.
Upon receiving a merge_shards request, Amazon
Kinesis Data Streams immediately returns a response and sets the
StreamStatus to UPDATING. After the operation is completed, Kinesis
Data Streams sets the StreamStatus to ACTIVE. Read and write
operations continue to work while the stream is in the UPDATING state.
You use describe_stream to determine the
shard IDs that are specified in the
merge_shards request.
If you try to operate on too many streams in parallel using
create_stream,
delete_stream,
merge_shards, or
split_shard, you receive a
LimitExceededException.
merge_shards has a limit of five transactions
per second per account.
kinesis_merge_shards(StreamName, ShardToMerge, AdjacentShardToMerge)[required] The name of the stream for the merge.
[required] The shard ID of the shard to combine with the adjacent shard for the merge.
[required] The shard ID of the adjacent shard for the merge.
An empty list.
svc$merge_shards( StreamName = "string", ShardToMerge = "string", AdjacentShardToMerge = "string" )