You can use this pattern to retrieve and summarize a list of documents from Amazon Simple Storage Service (Amazon S3) buckets in real time. The pattern provides example code to parallel read objects from S3 buckets on Amazon Web Services (AWS). The pattern showcases how to efficiently run I/O bound tasks with AWS Lambda functions using Python.

A financial company used this pattern in an interactive solution to manually approve or rejected correlated financial transactions in real time. The financial transaction documents were stored in an S3 bucket related to the market. An operator selected a list of documents from the S3 bucket, analyzed the total value of the transactions that the solution calculated, and decided to approve or reject the selected batch.