Amazon Athena

• It is a serverless interactive querying service
• We can take data stored in S3 and perform ad-hoc queries on the data paying only for the data consumed
• Athena uses a process named Schema-on-read - table-like translation
• Original data in S3 is never changed, it remains in its original form. It is translated to the predefined schema when it is read for processing
• Supported formats by Athena: XML, JSON, CSV/TSV, AVRO, PARQUET, ORC, Apache, CloudTrail, VPC Flowlogs, etc. Supports standard formats of structured data, semi-structured and unstructured data
• “Tables” are defined in advance in a data catalog and data is projected through when read. It allows SQL-like queries on data without transforming source data
• Athena has no infrastructure. We don’t need set up anything in advance
• Athena is ideal for situations where loading/transforming data isn’t desired
• It is preferred for querying AWS logs: VPC Flow Logs, CloudTrail, ELB logs, cost reports, etc
• Athena Federated Query: Athena now supports querying other data sources than S3. Requires a data source connector (AWS Lambda)