C# (CSharp) Amazon.Kinesis.Model Namespace

If tags have already been assigned to the stream, AddTagsToStream overwrites any existing tags that correspond to the specified tag keys.

This operation adds a new Amazon Kinesis stream to your AWS account. A stream captures and transports data records that are continuously emitted from different data sources or producers . Scale-out within an Amazon Kinesis stream is explicitly supported by means of shards, which are uniquely identified groups of data records in an Amazon Kinesis stream.

You specify and control the number of shards that a stream is composed of. Each shard can support up to 5 read transactions per second up to a maximum total of 2 MB of data read per second. Each shard can support up to 1000 write transactions per second up to a maximum total of 1 MB data written per second. You can add shards to a stream if the amount of data input increases and you can remove shards if the amount of data input decreases.

The stream name identifies the stream. The name is scoped to the AWS account used by the application. It is also scoped by region. That is, two streams in two different accounts can have the same name, and two streams in the same account, but in two different regions, can have the same name.

CreateStream is an asynchronous operation. Upon receiving a CreateStream request, Amazon Kinesis immediately returns and sets the stream status to CREATING. After the stream is created, Amazon Kinesis sets the stream status to ACTIVE. You should perform read and write operations only on an ACTIVE stream.

You receive a LimitExceededException when making a CreateStream request if you try to do one of the following:

• Have more than five streams in the CREATING state at any point in time.
• Create more shards than are authorized for your account.

Note: The default limit for an AWS account is two shards per stream. If you need to create a stream with more than two shards, contact AWS Support to increase the limit on your account.

You can use the DescribeStream operation to check the stream status, which is returned in StreamStatus .

CreateStream has a limit of 5 transactions per second per account.

This operation may result in lost data. For example, if the stream's retention period is 48 hours and is decreased to 24 hours, any data already in the stream that is older than 24 hours is inaccessible.

If the stream is in the ACTIVE state, you can delete it. After a DeleteStream request, the specified stream is in the DELETING state until Amazon Kinesis completes the deletion.

Note: Amazon Kinesis might continue to accept data read and write operations, such as PutRecord, PutRecords, and GetRecords, on a stream in the DELETING state until the stream deletion is complete.

When you delete a stream, any shards in that stream are also deleted, and any tags are dissociated from the stream.

You can use the DescribeStream operation to check the state of the stream, which is returned in StreamStatus.

DeleteStream has a limit of 5 transactions per second per account.

This operation returns the following information about the stream: the current status of the stream, the stream Amazon Resource Name (ARN), and an array of shard objects that comprise the stream. For each shard object there is information about the hash key and sequence number ranges that the shard spans, and the IDs of any earlier shards that played in a role in a MergeShards or SplitShard operation that created the shard. A sequence number is the identifier associated with every record ingested in the Amazon Kinesis stream. The sequence number is assigned by the Amazon Kinesis service when a record is put into the stream.

You can limit the number of returned shards using the Limit parameter. The number of shards in a stream may be too large to return from a single call to DescribeStream . You can detect this by using the HasMoreShards flag in the returned output. HasMoreShards is set to true when there is more data available.

If there are more shards available, you can request more shards by using the shard ID of the last shard returned by the DescribeStream request, in the ExclusiveStartShardId parameter in a subsequent request to DescribeStream . DescribeStream is a paginated operation.

DescribeStream has a limit of 10 transactions per second per account.

Represents the output of a DescribeStream operation.

Specify a shard iterator using the ShardIterator parameter. The shard iterator specifies the position in the shard from which you want to start reading data records sequentially. If there are no records available in the portion of the shard that the iterator points to, GetRecords returns an empty list. Note that it might take multiple calls to get to a portion of the shard that contains records.

You can scale by provisioning multiple shards per stream while considering service limits (for more information, see Streams Limits in the Amazon Kinesis Streams Developer Guide). Your application should have one thread per shard, each reading continuously from its stream. To read from a stream continually, call GetRecords in a loop. Use GetShardIterator to get the shard iterator to specify in the first GetRecords call. GetRecords returns a new shard iterator in NextShardIterator. Specify the shard iterator returned in NextShardIterator in subsequent calls to GetRecords. Note that if the shard has been closed, the shard iterator can't return more data and GetRecords returns null in NextShardIterator. You can terminate the loop when the shard is closed, or when the shard iterator reaches the record with the sequence number or other attribute that marks it as the last record to process.

Each data record can be up to 1 MB in size, and each shard can read up to 2 MB per second. You can ensure that your calls don't exceed the maximum supported size or throughput by using the Limit parameter to specify the maximum number of records that GetRecords can return. Consider your average record size when determining this limit.

The size of the data returned by GetRecords varies depending on the utilization of the shard. The maximum size of data that GetRecords can return is 10 MB. If a call returns this amount of data, subsequent calls made within the next 5 seconds throw ProvisionedThroughputExceededException. If there is insufficient provisioned throughput on the shard, subsequent calls made within the next 1 second throw ProvisionedThroughputExceededException. Note that GetRecords won't return any data when it throws an exception. For this reason, we recommend that you wait one second between calls to GetRecords; however, it's possible that the application will get exceptions for longer than 1 second.

To detect whether the application is falling behind in processing, you can use the MillisBehindLatest response attribute. You can also monitor the stream using CloudWatch metrics and other mechanisms (see Monitoring in the Amazon Kinesis Streams Developer Guide).

Each Amazon Kinesis record includes a value, ApproximateArrivalTimestamp, that is set when a stream successfully receives and stores a record. This is commonly referred to as a server-side timestamp, whereas a client-side timestamp is set when a data producer creates or sends the record to a stream (a data producer is any data source putting data records into a stream, for example with PutRecords). The timestamp has millisecond precision. There are no guarantees about the timestamp accuracy, or that the timestamp is always increasing. For example, records in a shard or across a stream might have timestamps that are out of order.

A shard iterator specifies the shard position from which to start reading data records sequentially. The position is specified using the sequence number of a data record in a shard. A sequence number is the identifier associated with every record ingested in the stream, and is assigned when a record is put into the stream. Each stream has one or more shards.

You must specify the shard iterator type. For example, you can set the ShardIteratorType parameter to read exactly from the position denoted by a specific sequence number by using the AT_SEQUENCE_NUMBER shard iterator type, or right after the sequence number by using the AFTER_SEQUENCE_NUMBER shard iterator type, using sequence numbers returned by earlier calls to PutRecord, PutRecords, GetRecords, or DescribeStream. In the request, you can specify the shard iterator type AT_TIMESTAMP to read records from an arbitrary point in time, TRIM_HORIZON to cause ShardIterator to point to the last untrimmed record in the shard in the system (the oldest data record in the shard), or LATEST so that you always read the most recent data in the shard.

When you read repeatedly from a stream, use a GetShardIterator request to get the first shard iterator for use in your first GetRecords request and for subsequent reads use the shard iterator returned by the GetRecords request in NextShardIterator. A new shard iterator is returned by every GetRecords request in NextShardIterator, which you use in the ShardIterator parameter of the next GetRecords request.

If a GetShardIterator request is made too often, you receive a ProvisionedThroughputExceededException. For more information about throughput limits, see GetRecords, and Streams Limits in the Amazon Kinesis Streams Developer Guide.

If the shard is closed, GetShardIterator returns a valid iterator for the last sequence number of the shard. Note that a shard can be closed as a result of using SplitShard or MergeShards.

GetShardIterator has a limit of 5 transactions per second per account per open shard.

The range of possible hash key values for the shard, which is a set of ordered contiguous positive integers.

Upon choosing a longer stream retention period, this operation will increase the time period records are accessible that have not yet expired. However, it will not make previous data that has expired (older than the stream's previous retention period) accessible after the operation has been called. For example, if a stream's retention period is set to 24 hours and is increased to 168 hours, any data that is older than 24 hours will remain inaccessible to consumer applications.

The number of streams may be too large to return from a single call to ListStreams. You can limit the number of returned streams using the Limit parameter. If you do not specify a value for the Limit parameter, Amazon Kinesis uses the default limit, which is currently 10.

You can detect if there are more streams available to list by using the HasMoreStreams flag from the returned output. If there are more streams available, you can request more streams by using the name of the last stream returned by the ListStreams request in the ExclusiveStartStreamName parameter in a subsequent request to ListStreams. The group of stream names returned by the subsequent request is then added to the list. You can continue this process until all the stream names have been collected in the list.

ListStreams has a limit of 5 transactions per second per account.

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.

You must specify the name of the stream that captures, stores, and transports the data; a partition key; and the data blob itself.

The data blob can be any type of data; for example, a segment from a log file, geographic/location data, website clickstream data, and so on.

The partition key is used by Amazon Kinesis to distribute data across shards. Amazon Kinesis segregates the data records that belong to a stream into multiple shards, using the partition key associated with each data record to determine which shard a given data record belongs to.

Partition keys are Unicode strings, with a maximum length limit of 256 characters for each key. An MD5 hash function is used to map partition keys to 128-bit integer values and to map associated data records to shards using the hash key ranges of the shards. You can override hashing the partition key to determine the shard by explicitly specifying a hash value using the ExplicitHashKey parameter. For more information, see Adding Data to a Stream in the Amazon Kinesis Streams Developer Guide.

PutRecord returns the shard ID of where the data record was placed and the sequence number that was assigned to the data record.

Sequence numbers increase over time and are specific to a shard within a stream, not across all shards within a stream. To guarantee strictly increasing ordering, write serially to a shard and use the SequenceNumberForOrdering parameter. For more information, see Adding Data to a Stream in the Amazon Kinesis Streams Developer Guide.

If a PutRecord request cannot be processed because of insufficient provisioned throughput on the shard involved in the request, PutRecord throws ProvisionedThroughputExceededException.

Data records are accessible for only 24 hours from the time that they are added to a stream.

Represents the output of a PutRecord operation.

Each PutRecords request can support up to 500 records. Each record in the request can be as large as 1 MB, up to a limit of 5 MB for the entire request, including partition keys. Each shard can support writes up to 1,000 records per second, up to a maximum data write total of 1 MB per second.

You must specify the name of the stream that captures, stores, and transports the data; and an array of request Records, with each record in the array requiring a partition key and data blob. The record size limit applies to the total size of the partition key and data blob.

The data blob can be any type of data; for example, a segment from a log file, geographic/location data, website clickstream data, and so on.

The partition key is used by Amazon Kinesis as input to a hash function that maps the partition key and associated data to a specific shard. An MD5 hash function is used to map partition keys to 128-bit integer values and to map associated data records to shards. As a result of this hashing mechanism, all data records with the same partition key map to the same shard within the stream. For more information, see Adding Data to a Stream in the Amazon Kinesis Streams Developer Guide.

Each record in the Records array may include an optional parameter, ExplicitHashKey, which overrides the partition key to shard mapping. This parameter allows a data producer to determine explicitly the shard where the record is stored. For more information, see Adding Multiple Records with PutRecords in the Amazon Kinesis Streams Developer Guide.

The PutRecords response includes an array of response Records. Each record in the response array directly correlates with a record in the request array using natural ordering, from the top to the bottom of the request and response. The response Records array always includes the same number of records as the request array.

The response Records array includes both successfully and unsuccessfully processed records. Amazon Kinesis attempts to process all records in each PutRecords request. A single record failure does not stop the processing of subsequent records.

A successfully-processed record includes ShardId and SequenceNumber values. The ShardId parameter identifies the shard in the stream where the record is stored. The SequenceNumber parameter is an identifier assigned to the put record, unique to all records in the stream.

An unsuccessfully-processed record includes ErrorCode and ErrorMessage values. ErrorCode reflects the type of error and can be one of the following values: ProvisionedThroughputExceededException or InternalFailure. ErrorMessage provides more detailed information about the ProvisionedThroughputExceededException exception including the account ID, stream name, and shard ID of the record that was throttled. For more information about partially successful responses, see Adding Multiple Records with PutRecords in the Amazon Kinesis Streams Developer Guide.

By default, data records are accessible for only 24 hours from the time that they are added to an Amazon Kinesis stream. This retention period can be modified using the DecreaseStreamRetentionPeriod and IncreaseStreamRetentionPeriod operations.

The unit of data of the Amazon Kinesis stream, which is composed of a sequence number, a partition key, and a data blob.

If you specify a tag that does not exist, it is ignored.

The range of possible sequence numbers for the shard.

This operation splits a shard into two new shards in the stream, to increase the stream's capacity to ingest and transport data. SplitShard is called when there is a need to increase the overall capacity of stream because of an expected increase in the volume of data records being ingested.

SplitShard can also be used when a given shard appears to be approaching its maximum utilization, for example, when the set of producers sending data into the specific shard are suddenly sending more than previously anticipated. You can also call the SplitShard operation to increase stream capacity, so that more Amazon Kinesis applications can simultaneously read data from the stream for real-time processing.

The SplitShard operation requires that you specify the shard to be split and the new hash key, which is the position in the shard where the shard gets split in two. In many cases, the new hash key might simply be the average of the beginning and ending hash key, but it can be any hash key value in the range being mapped into the shard. For more information about splitting shards, see the Amazon Kinesis Developer Guide .

You can use the DescribeStream operation to determine the shard ID and hash key values for the ShardToSplit and NewStartingHashKey parameters that are specified in the SplitShard request.

SplitShard is an asynchronous operation. Upon receiving a SplitShard request, Amazon Kinesis immediately returns a response and sets the stream status to UPDATING. After the operation is completed, Amazon Kinesis sets the stream status to ACTIVE. Read and write operations continue to work while the stream is in the UPDATING state.

You can use DescribeStream to check the status of the stream, which is returned in StreamStatus . If the stream is in the ACTIVE state, you can call SplitShard . If a stream is in CREATING or UPDATING or DELETING states, then Amazon Kinesis returns a ResourceInUseException .

If the specified stream does not exist, Amazon Kinesis returns a ResourceNotFoundException . If you try to create more shards than are authorized for your account, you receive a LimitExceededException .

Note: The default limit for an AWS account is two shards per stream. If you need to create a stream with more than two shards, contact AWS Support to increase the limit on your account.

If you try to operate on too many streams in parallel using CreateStream, DeleteStream, MergeShards or SplitShard, you will receive a LimitExceededException .

SplitShard has limit of 5 transactions per second per account.

Updating the shard count is an asynchronous operation. Upon receiving the request, Amazon Kinesis returns immediately and sets the status of the stream to UPDATING. After the update is complete, Amazon Kinesis sets the status of the stream back to ACTIVE. 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 UPDATING.

To update the shard count, Amazon Kinesis performs splits and merges and 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 a rate limit of twice per rolling 24 hour period. You cannot scale above double your current shard count, scale below half your current shard count, or exceed the shard limits for your account.

For the default limits for an AWS account, see Streams Limits in the Amazon Kinesis Streams Developer Guide. If you need to increase a limit, contact AWS Support.