LSNs
LSNs, short for log sequence numbers, are identifiers assigned to entries in a database's transaction log or write-ahead log. Each log record receives a unique, monotonically increasing LSN as it is written. The LSN serves as a location pointer within the log and provides a stable point to reference for recovery and replication operations.
How they are used: During crash recovery, the database uses LSNs to determine which log records must
Scope and examples: The term LSN is used in several systems, notably SQL Server, PostgreSQL, and MySQL.
Limitations: LSNs reflect log positions, not wall-clock time; they are themselves not meaningful outside the local