13.2. DB2 Transaction Logs

DB2 uses transaction logs to record all changes to your database so that they can be either reapplied or rolled back in the event of problems.

13.2.1. Understanding the DB2 Transaction Logs

The ability to perform both crash recovery and roll forward recovery is provided by the database transaction logs. Transaction logs keep track of changes made to database objects and data. During the recovery process, DB2 examines these logs and decides which changes to redo or undo.

Logs can be stored in files or in raw devices. In this chapter, we use files in our examples for simplicity. To ensure data integrity, DB2 uses a “write-ahead logging” mechanism to write to the logs before writing (externalizing) the database changes ...

Get Understanding DB2®: Learning Visually with Examples now with O’Reilly online learning.

O’Reilly members experience live online training, plus books, videos, and digital content from 200+ publishers.