* Introducing support for ListShards API. This API is used in place of DescribeStream API to provide more throughput during ShardSyncTask. Please consult the [AWS Documentation for ListShards](https://docs.aws.amazon.com/kinesis/latest/APIReference/API_ListShards.html) for more information.
* Added configuration parameters for ListShards usage
| Name | Default | Description |
| ---- | ------- | ----------- |
| [listShardsBackoffTimeInMillis](https://github.com/awslabs/amazon-kinesis-client/blob/3ae916c5fcdccd6b835c86ba7f6f53dd5b4c8b04/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1412) | 1500 ms | This is the default backoff time between 2 ListShards calls when throttled. |
| [listShardsRetryAttempts](https://github.com/awslabs/amazon-kinesis-client/blob/3ae916c5fcdccd6b835c86ba7f6f53dd5b4c8b04/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1423) | 50 | This is the maximum number of times the KinesisProxy will retry to make ListShards calls on being throttled. |
* Updating the version of AWS Java SDK to 1.11.272.
* Deprecated certain [KinesisProxy](https://github.com/awslabs/amazon-kinesis-client/blob/3ae916c5fcdccd6b835c86ba7f6f53dd5b4c8b04/src/main/java/com/amazonaws/services/kinesis/clientlibrary/proxies/KinesisProxy.java) constructors.
* Allow disabling check for the case where a child shard has an open parent shard.
There is a race condition where it's possible for the a parent shard to appear open, while having child shards. This check can now be disabled by setting [`ignoreUnexpectedChildShards`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1037) to true.
Logging long running tasks can be enabled by setting the following configuration property:
| Name | Default | Description |
| ---- | ------- | ----------- |
| [`logWarningForTaskAfterMillis`](https://github.com/awslabs/amazon-kinesis-client/blob/3de901ea9327370ed732af86c4d4999c8d99541c/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1367) | Not set | Milliseconds after which the logger will log a warning message for the long running task |
Added better handling of DynamoDB failures when updating leases. These failures would occur when a request to DynamoDB appeared to fail, but was actually successful.
Prefetching will retrieve and queue additional records from Kinesis while the application is processing existing records.
Prefetching can be enabled by setting [`dataFetchingStrategy`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1317) to `PREFETCH_CACHED`. Once enabled an additional fetching thread will be started to retrieve records from Kinesis. Retrieved records will be held in a queue until the application is ready to process them.
Pre-fetching supports the following configuration values:
| Name | Default | Description |
| ---- | ------- | ----------- |
| [`dataFetchingStrategy`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1317) | `DEFAULT` | Which data fetching strategy to use |
| [`maxPendingProcessRecordsInput`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1296) | 3 | The maximum number of process records input that can be queued |
| [`maxCacheByteSize`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1307) | 8 MiB | The maximum number of bytes that can be queued |
| [`maxRecordsCount`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1326) | 30,000 | The maximum number of records that can be queued |
| [`idleMillisBetweenCalls`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L1353) | 1,500 ms | The amount of time to wait between calls to Kinesis |
* Only advance the shard iterator for the accepted response.
This fixes a race condition in the `KinesisDataFetcher` when it's being used to make asynchronous requests. The shard iterator is now only advanced when the retriever calls `DataFetcherResult#accept()`.
* Call shutdown on the retriever when the record processor is being shutdown
This fixes a bug that could leak threads if using the [`AsynchronousGetRecordsRetrievalStrategy`](https://github.com/awslabs/amazon-kinesis-client/blob/9a82b6bd05b3c9c5f8581af007141fa6d5f0fc4e/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/AsynchronousGetRecordsRetrievalStrategy.java#L42) is being used.
The asynchronous retriever is only used when [`KinesisClientLibConfiguration#retryGetRecordsInSeconds`](https://github.com/awslabs/amazon-kinesis-client/blob/01d2688bc6e68fd3fe5cb698cb65299d67ac930d/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L227), and [`KinesisClientLibConfiguration#maxGetRecordsThreadPool`](https://github.com/awslabs/amazon-kinesis-client/blob/01d2688bc6e68fd3fe5cb698cb65299d67ac930d/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/KinesisClientLibConfiguration.java#L230) are set.
Applications can now set a pending checkpoint, before completing the checkpoint operation. Once the application has completed its checkpoint steps, the final checkpoint will clear the pending checkpoint.
Should the checkpoint fail the attempted sequence number is provided in the [`InitializationInput#getPendingCheckpointSequenceNumber`](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/types/InitializationInput.java#L81) otherwise the value will be null.
* Support timeouts, and retry for GetRecords calls.
Applications can now set timeouts for GetRecord calls to Kinesis. As part of setting the timeout, the application must also provide a thread pool size for concurrent requests.
When writes, or reads, to the lease table are throttled a warning will be emitted. If you're seeing this warning you should increase the IOPs for your lease table to prevent processing delays.
* Support configuring the graceful shutdown timeout for MultiLang Clients
This adds support for setting the timeout that the Java process will wait for the MutliLang client to complete graceful shutdown. The timeout can be configured by adding `shutdownGraceMillis` to the properties file set to the number of milliseconds to wait.
* Support timeouts for calls to the MultiLang Daemon
This adds support for setting a timeout when dispatching records to the client record processor. If the record processor doesn't respond within the timeout the parent Java process will be terminated. This is a temporary fix to handle cases where the KCL becomes blocked while waiting for a client record processor.
The timeout for the this can be set by adding `timeoutInSeconds = <timeout value>`. The default for this is no timeout.
__Setting this can cause the KCL to exit suddenly, before using this ensure that you have an automated restart for your application__
The MultiLangDaemon has been upgraded to use the v2 interfaces, which allows access to enhanced checkpointing, and more information during record processor initialization. The MultiLangDaemon clients must be updated before they can take advantage of these new features.
## Release 1.7.1 (November 3, 2016)
* General
* Allow disabling shard synchronization at startup.
* Applications can disable shard synchronization at startup. Disabling shard synchronization can application startup times for very large streams.
* Applications can now request a graceful shutdown, and record processors that implement the IShutdownNotificationAware will be given a chance to checkpoint before being shutdown.
* This adds a [new interface](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/interfaces/v2/IShutdownNotificationAware.java), and a [new method on Worker](https://github.com/awslabs/amazon-kinesis-client/blob/master/src/main/java/com/amazonaws/services/kinesis/clientlibrary/lib/worker/Worker.java#L539).
* Add support for time based iterators ([See GetShardIterator Documentation](http://docs.aws.amazon.com/kinesis/latest/APIReference/API_GetShardIterator.html))
The `KinesisClientLibconfiguration` now supports providing a `ShardPrioritization` strategy. This strategy controls how the `Worker` determines which `ShardConsumer` to call next. This can improve processing for streams that split often, such as DynamoDB Streams.
* Remove direct dependency on `aws-java-sdk-core`, to allow independent versioning.
* Artifacts are now signed by the identity `Amazon Kinesis Tools <amazon-kinesis-tools@amazon.com>`
## Release 1.6.3 (May 12, 2016)
* Fix format exception caused by DEBUG log in LeaseTaker [Issue # 68](https://github.com/awslabs/amazon-kinesis-client/issues/68)
## Release 1.6.2 (March 23, 2016)
* Support for specifying max leases per worker and max leases to steal at a time.
* Support for specifying initial DynamoDB table read and write capacity.
* Support for parallel lease renewal.
* Support for graceful worker shutdown.
* Change DefaultCWMetricsPublisher log level to debug. [PR # 49](https://github.com/awslabs/amazon-kinesis-client/pull/49)
* Avoid NPE in MLD record processor shutdown if record processor was not initialized. [Issue # 29](https://github.com/awslabs/amazon-kinesis-client/issues/29)
## Release 1.6.1 (September 23, 2015)
* Expose [approximateArrivalTimestamp](http://docs.aws.amazon.com/kinesis/latest/APIReference/API_GetRecords.html) for Records in processRecords API call.
## Release 1.6.0 (July 31, 2015)
* Restores compatibility with [dynamodb-streams-kinesis-adapter](https://github.com/awslabs/dynamodb-streams-kinesis-adapter) (which was broken in 1.4.0).
## Release 1.5.1 (July 20, 2015)
* KCL maven artifact 1.5.0 does not work with JDK 7. This release addresses this issue.
* Support metrics level and dimension configurations to control CloudWatch metrics emitted by the KCL.
* Add new metrics that track time spent in record processor methods.
* Disable WorkerIdentifier dimension by default.
* **Exception Reporting** — Do not silently ignore exceptions in ShardConsumer.
* **AWS SDK Component Dependencies** — Depend only on AWS SDK components that are used.
## Release 1.4.0 (June 2, 2015)
* Integration with the **[Kinesis Producer Library (KPL)][kinesis-guide-kpl]**
* Automatically de-aggregate records put into the Kinesis stream using the KPL.
* Support checkpointing at the individual user record level when multiple user records are aggregated into one Kinesis record using the KPL.
See [Consumer De-aggregation with the KCL][kinesis-guide-consumer-deaggregation] for details.
## Release 1.3.0 (May 22, 2015)
* A new metric called "MillisBehindLatest", which tracks how far consumers are from real time, is now uploaded to CloudWatch.
## Release 1.2.1 (January 26, 2015)
* **MultiLangDaemon** — Changes to the MultiLangDaemon to make it easier to provide a custom worker.
## Release 1.2 (October 21, 2014)
* **Multi-Language Support** — Amazon KCL now supports implementing record processors in any language by communicating with the daemon over [STDIN and STDOUT][multi-lang-protocol]. Python developers can directly use the [Amazon Kinesis Client Library for Python][kclpy] to write their data processing applications.
## Release 1.1 (June 30, 2014)
* **Checkpointing at a specific sequence number** — The IRecordProcessorCheckpointer interface now supports checkpointing at a sequence number specified by the record processor.
* **Set region** — KinesisClientLibConfiguration now supports setting the region name to indicate the location of the Amazon Kinesis service. The Amazon DynamoDB table and Amazon CloudWatch metrics associated with your application will also use this region setting.
