AWS Lambda 按序处理同一个 Kinesis Shard 中的消息

当 AWS Lambda 由 Kinesis 消息来触发时,一个 Kinesis Shard 会相应启动一个 Lambda 实例,比如说 Kinesis Stream 有 5 个 Shards, 那同时只会启动 5 个 Lambda 实例。那么把多条消息发送到同一个 Kinesis Shard 中去,这些消息会被如何消费呢?答案是按顺消息,不管这些消息是否被不同的 Lambda 实例处理。本文就是关于怎么去理解 https://aws.amazon.com/lambda/faqs/ 的下面那段话的内容:

Q: How does AWS Lambda process data from Amazon Kinesis streams and Amazon DynamoDB Streams?
AWS Lambda 如何处理来自于 Amazon Kinesis 和 DynamoDB 的数据

The Amazon Kinesis and DynamoDB Streams records sent to your AWS Lambda function are strictly serialized, per shard. This means that if you put two records in the same shard, Lambda guarantees that your Lambda function will be successfully invoked with the first record before it is invoked with the second record. If the invocation for one record times out, is throttled, or encounters any other error, Lambda will retry until it succeeds (or the record reaches its 24-hour expiration) before moving on to the next record. The ordering of records across different shards is not guaranteed, and processing of each shard happens in parallel.

从 Kinesis 和 DynamoDB 单个 Shard 上的记录会被 Lambda 严格的按序处理。这意味着如果你送两条记录到相同的 Shard, Lambda 将会保证第一条记录成功处理后才会处理第二条记录。假如处理第一条记录时超时,或超过资源使用上限,或碰到任何错误, Lambda 将会不断重试直到成功(或记录在 24 小时后过期), 而后才会去处理下一条记录。跨 Shard 的记录不保证到达顺序,且是并行处理多个 Shard 来的记录。

可以做几个试验,下面的代码可以保证消息总是被发送到同一个 Kinesis Shard,因为 PartitionKey 参数是一个常量 阅读全文 >>

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