GetRecordsCommand

Suggest an Edit

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.

Example Syntax

Use a bare-bones client and the command you need to make an API call.

import { KinesisClient, GetRecordsCommand } from "@aws-sdk/client-kinesis"; // ES Modules import
// const { KinesisClient, GetRecordsCommand } = require("@aws-sdk/client-kinesis"); // CommonJS import
const client = new KinesisClient(config);
const input = { // GetRecordsInput
  ShardIterator: "STRING_VALUE", // required
  Limit: Number("int"),
  StreamARN: "STRING_VALUE",
};
const command = new GetRecordsCommand(input);
const response = await client.send(command);
// { // GetRecordsOutput
//   Records: [ // RecordList // required
//     { // Record
//       SequenceNumber: "STRING_VALUE", // required
//       ApproximateArrivalTimestamp: new Date("TIMESTAMP"),
//       Data: new Uint8Array(), // required
//       PartitionKey: "STRING_VALUE", // required
//       EncryptionType: "NONE" || "KMS",
//     },
//   ],
//   NextShardIterator: "STRING_VALUE",
//   MillisBehindLatest: Number("long"),
//   ChildShards: [ // ChildShardList
//     { // ChildShard
//       ShardId: "STRING_VALUE", // required
//       ParentShards: [ // ShardIdList // required
//         "STRING_VALUE",
//       ],
//       HashKeyRange: { // HashKeyRange
//         StartingHashKey: "STRING_VALUE", // required
//         EndingHashKey: "STRING_VALUE", // required
//       },
//     },
//   ],
// };

GetRecordsCommand Input

See GetRecordsCommandInput for more details

Parameter
Type
Description
ShardIterator
Required
string | undefined

The position in the shard from which you want to start sequentially reading data records. A shard iterator specifies this position using the sequence number of a data record in the shard.

Limit
number | undefined

The maximum number of records to return. Specify a value of up to 10,000. If you specify a value that is greater than 10,000, GetRecords throws InvalidArgumentException. The default value is 10,000.

StreamARN
string | undefined

The ARN of the stream.

GetRecordsCommand Output

See GetRecordsCommandOutput for details

Parameter
Type
Description
$metadata
Required
ResponseMetadata
Metadata pertaining to this request.
Records
Required
_Record[] | undefined

The data records retrieved from the shard.

ChildShards
ChildShard[] | undefined

The list of the current shard's child shards, returned in the GetRecords API's response only when the end of the current shard is reached.

MillisBehindLatest
number | undefined

The number of milliseconds the GetRecords response is from the tip of the stream, indicating how far behind current time the consumer is. A value of zero indicates that record processing is caught up, and there are no new records to process at this moment.

NextShardIterator
string | undefined

The next position in the shard from which to start sequentially reading data records. If set to null, the shard has been closed and the requested iterator does not return any more data.

Throws

Name
Fault
Details
AccessDeniedException
client

Specifies that you do not have the permissions required to perform this operation.

ExpiredIteratorException
client

The provided iterator exceeds the maximum age allowed.

InvalidArgumentException
client

A specified parameter exceeds its restrictions, is not supported, or can't be used. For more information, see the returned message.

KMSAccessDeniedException
client

The ciphertext references a key that doesn't exist or that you don't have access to.

KMSDisabledException
client

The request was rejected because the specified customer master key (CMK) isn't enabled.

KMSInvalidStateException
client

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
client

The request was rejected because the specified entity or resource can't be found.

KMSOptInRequired
client

The Amazon Web Services access key ID needs a subscription for the service.

KMSThrottlingException
client

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
client

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
client

The requested resource could not be found. The stream might not be specified correctly.

KinesisServiceException
Base exception class for all service exceptions from Kinesis service.