Background

Anki’s method for determining the last review time has two main issues:

• Performance: Querying the revlog is slow for batch operations.
• Accuracy: Estimations based on due and interval fields can be incorrect, especially when modified manually or by add-ons.

Key Changes

• Schema Update:
  • Added last_review_time_secs (optional int64) to the protobuf definition.
• Data Structures:
  • Introduced last_review_time: Option<TimestampSecs> to the Rust Card struct.
• Serialization:
  • Integrated last_review_time into read/write logic.
• Review Logic:
  • Updated to store exact timestamp during card reviews.
• Calculation Logic:
  • Functions now prioritize last_review_time over legacy methods.

Affected Components

• Card protobuf and Rust data structures
• Serialization/deserialization
• Browser table and scheduling logic
• Statistics
• Sync functionality

Benefits

• Improved Performance: Avoids costly revlog queries.
• Better Accuracy: Captures actual review timestamp.
• Backward Compatibility: Falls back to older methods if the new field is absent.