Copyright | (c) 2013-2016 Brendan Hay |
---|---|
License | Mozilla Public License, v. 2.0. |
Maintainer | Brendan Hay <brendan.g.hay@gmail.com> |
Stability | auto-generated |
Portability | non-portable (GHC extensions) |
Safe Haskell | None |
Language | Haskell2010 |
Merges two adjacent shards in a 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.
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 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.
Creating a Request
Creates a value of MergeShards
with the minimum fields required to make a request.
Use one of the following lenses to modify other fields as desired:
data MergeShards Source
Represents the input for MergeShards
.
See: mergeShards
smart constructor.
Request Lenses
msStreamName :: Lens' MergeShards Text Source
The name of the stream for the merge.
msShardToMerge :: Lens' MergeShards Text Source
The shard ID of the shard to combine with the adjacent shard for the merge.
msAdjacentShardToMerge :: Lens' MergeShards Text Source
The shard ID of the adjacent shard for the merge.
Destructuring the Response
mergeShardsResponse :: MergeShardsResponse Source
Creates a value of MergeShardsResponse
with the minimum fields required to make a request.