Everything you don’t need to know about Amazon Aurora DSQL: Part 5 – How the service uses clocks

This article explains how Amazon Aurora DSQL uses hybrid logical clocks and Amazon Time Sync Service to maintain strong consistency across distributed, multi-Region deployments.

• Aurora DSQL employs active-active design with all nodes serving read and write traffic
• Hybrid logical clocks combine physical clock accuracy with logical clock causality tracking
• Amazon Time Sync Service provides microsecond-level precision using atomic clocks and GPS
• Read-only transactions achieve linearizability through upper error bound timestamp selection
• Transactions receive start and commit timestamps to ensure consistent ordering across regions
• System delays client responses until timestamp bounds verified in the past
• Prevents timing anomalies where later transactions could see earlier commit states
• Enables financial and ecommerce use cases requiring strong consistency guarantees

Aurora DSQL's hybrid clock approach delivers global strong consistency with minimal latency by combining precise time synchronization with logical ordering mechanisms.