Oracle Database - UNDO (Rollback Segment)

1 - What is UNDO ?

rollback journal in Oracle.

3 - Support

3.1 - ORA-01555 - snapshot too old

ORA-01555: snapshot too old: rollback segment number 12 with name "_SYSSMU12_253434260$" too small '
  • The UNDO space was too small. The SELECT statement was killed letting the DML operations continue.
  • Of the Minimum Undo Retention Period was achieved Minimum Undo Retention

See AskTom

4 - Reference/Documentation

db/oracle/undo.txt ยท Last modified: 2018/10/18 11:18 by gerardnico