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Gets data records from a Kinesis data stream's shard.
When invoking this API, you must use either the StreamARN
or the StreamName
parameter, or both. It is recommended that you use the StreamARN
input parameter
when you invoke this API.
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. 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 Amazon
Kinesis Data Streams Limits in the Amazon Kinesis Data 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. 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 MiB in size, and each shard can read up to 2 MiB 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 maximum number of records that can be returned per call is 10,000.
The size of the data returned by GetRecords varies depending on the utilization
of the shard. It is recommended that consumer applications retrieve records via the
GetRecords
command using the 5 TPS limit to remain caught up. Retrieving records
less frequently can lead to consumer applications falling behind. The maximum size
of data that GetRecords can return is 10 MiB. 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 stream, subsequent calls made
within the next 1 second throw ProvisionedThroughputExceededException
. GetRecords
doesn't return any data when it throws an exception. For this reason, we recommend
that you wait 1 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 Data 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 time stamp, whereas a client-side time stamp 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 time
stamp has millisecond precision. There are no guarantees about the time stamp accuracy,
or that the time stamp is always increasing. For example, records in a shard or across
a stream might have time stamps that are out of order.
This operation has a limit of five transactions per second per shard.
This is an asynchronous operation using the standard naming convention for .NET 4.5 or higher. For .NET 3.5 the operation is implemented as a pair of methods using the standard naming convention of BeginGetRecords and EndGetRecords.
Namespace: Amazon.Kinesis
Assembly: AWSSDK.Kinesis.dll
Version: 3.x.y.z
public virtual Task<GetRecordsResponse> GetRecordsAsync( GetRecordsRequest request, CancellationToken cancellationToken )
Container for the necessary parameters to execute the GetRecords service method.
A cancellation token that can be used by other objects or threads to receive notice of cancellation.
Exception | Condition |
---|---|
AccessDeniedException | Specifies that you do not have the permissions required to perform this operation. |
ExpiredIteratorException | The provided iterator exceeds the maximum age allowed. |
InvalidArgumentException | A specified parameter exceeds its restrictions, is not supported, or can't be used. For more information, see the returned message. |
KMSAccessDeniedException | The ciphertext references a key that doesn't exist or that you don't have access to. |
KMSDisabledException | The request was rejected because the specified customer master key (CMK) isn't enabled. |
KMSInvalidStateException | The request was rejected because the state of the specified resource isn't valid for this request. For more information, see How Key State Affects Use of a Customer Master Key in the Amazon Web Services Key Management Service Developer Guide. |
KMSNotFoundException | The request was rejected because the specified entity or resource can't be found. |
KMSOptInRequiredException | The Amazon Web Services access key ID needs a subscription for the service. |
KMSThrottlingException | The request was denied due to request throttling. For more information about throttling, see Limits in the Amazon Web Services Key Management Service Developer Guide. |
ProvisionedThroughputExceededException | The request rate for the stream is too high, or the requested data is too large for the available throughput. Reduce the frequency or size of your requests. For more information, see Streams Limits in the Amazon Kinesis Data Streams Developer Guide, and Error Retries and Exponential Backoff in Amazon Web Services in the Amazon Web Services General Reference. |
ResourceNotFoundException | The requested resource could not be found. The stream might not be specified correctly. |
.NET Core App:
Supported in: 3.1
.NET Standard:
Supported in: 2.0
.NET Framework:
Supported in: 4.5