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Amazon Kinesis Streams
Developer Guide

Key Concepts

The following sections contain concepts and terminology necessary to understand and benefit from the KPL.

Records

In this guide, we distinguish between KPL user records and Streams records. When we use the term record without a qualifier, we refer to a KPL user record. When we refer to a Streams record, we will explicitly say Streams record.

A KPL user record is a blob of data that has particular meaning to the user. Examples include a JSON blob representing a UI event on a web site, or a log entry from a web server.

A Streams record is an instance of the Record data structure defined by the Streams service API. It contains a partition key, sequence number, and a blob of data.

Batching

Batching refers to performing a single action on multiple items instead of repeatedly performing the action on each individual item.

In this context, the "item" is a record, and the action is sending it to Streams. In a non-batching situation, you would place each record in a separate Streams record and make one HTTP request to send it to Streams. With batching, each HTTP request can carry multiple records instead of just one.

The KPL supports two types of batching:

  • Aggregation – Storing multiple records within a single Streams record.

  • Collection – Using the API operation PutRecords to send multiple Streams records to one or more shards in your Amazon Kinesis stream.

The two types of KPL batching are designed to co-exist and can be turned on or off independently of one another. By default, both are turned on.

Aggregation

Aggregation refers to the storage of multiple records in a Streams record. Aggregation allows customers to increase the number of records sent per API call, which effectively increases producer throughput.

Streams shards support up to 1,000 Streams records per second, or 1 MB throughput. The Streams records per second limit binds customers with records smaller than 1 KB. Record aggregation allows customers to combine multiple records into a single Streams record. This allows customers to improve their per shard throughput.

Consider the case of one shard in region us-east-1 that is currently running at a constant rate of 1,000 records per second, with records that are 512 bytes each. With KPL aggregation, you can pack one thousand records into only 10 Streams records, reducing the RPS to 10 (at 50 KB each).

Collection

Collection refers to batching multiple Streams records and sending them in a single HTTP request with a call to the API operation PutRecords, instead of sending each Streams record in its own HTTP request.

This increases throughput compared to using no collection because it reduces the overhead of making many separate HTTP requests. In fact, PutRecords itself was specifically designed for this purpose.

Collection differs from aggregation in that it is working with groups of Streams records. The Streams records being collected can still contain multiple records from the user. The relationship can be visualized as such:

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record 0 --| record 1 | [ Aggregation ] ... |--> Amazon Kinesis record 0 --| ... | | record A --| | | ... ... | | record K --| | record L | | [ Collection ] ... |--> Amazon Kinesis record C --|--> PutRecords Request ... | | record S --| | | ... ... | | record AA--| | record BB | | ... |--> Amazon Kinesis record M --| ... | record ZZ--|