ORA-01555

How to Resolve ORA-01555 UNDO_RETENTION

by Ed Chen
April 8, 2016December 11, 2022

ORA-01555 UNDO_RETENTION Let's see the error ORA-01555 UNDO_RETENTION first: Description ORA-01555: snapshot too old: rollback segment number string with name "string" too small Cause rollback… Read More »

UNDO_RETENTION, How and Why

by Ed Chen
April 7, 2016December 11, 2022

UNDO_RETENTION At times, you may find out or feel that UNDO_RETENTION is useless at all. Raising the number of seconds cannot resolve ORA-01555. This is… Read More »

Oracle Undo Tablespace Usage

by Ed Chen
May 28, 2014February 2, 2022
2 Comments

The first purpose of using UNDO is for storing all uncommitted data in case we need to undo uncommitted data in rollback or after system… Read More »