redbookcover.gif (13955 bytes) Readings in Database Systems, 3rd Edition

Stonebraker & Hellerstein, eds.

Simple Transaction Abort

For now, consider an explicit abort of a Xact.

No crash involved.

We want to “play back” the log in reverse order, UNDOing updates.

Get lastLSN of Xact from Xact table.
Can follow chain of log records backward via the prevLSN field.
Before starting UNDO, write an Abort log record.
For recovering from crash during UNDO!

Previous slide Next slide Back to first slide View graphic version

1998, Joseph M. Hellerstein.  Last modified 08/17/98.
Feedback welcomed.