Versatile in-memory database recovery using logical log records

摘要

The subject disclosure relates to a database recovery technique that implements various aspects of transaction logging to optimize database recovery performance. Transactions are logged logically with no reference to physical location, which enables logging to be performed via multiple independent log streams in parallel. A set of log streams can further be adjusted to conform to a local configuration of a mirror or secondary node in order to increase mirroring flexibility. Additionally, individual transactions or groups of transactions are recorded using a single log record, which contains timestamp information to enable database recovery without reference to physical checkpoint files. Further, techniques are provided herein for processing transactions without Write Ahead Logging or hardening of undo information. As further described herein, a transaction can be committed via a set of hierarchical stages, which in turn can facilitate integration of an in-memory database system with one or more external database systems.