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ORA-01555: snapshot too old with manual undo - Causes and Solutions (Doc ID 1005107.6)

Last updated on JANUARY 30, 2022

Applies to:

Oracle Database - Enterprise Edition - Version to [Release 8.1.7 to 11.1]
Oracle Database Cloud Schema Service - Version N/A and later
Gen 1 Exadata Cloud at Customer (Oracle Exadata Database Cloud Machine) - Version N/A and later
Oracle Cloud Infrastructure - Database Service - Version N/A and later
Oracle Database Backup Service - Version N/A and later
Information in this document applies to any platform.


NOTE: In the images and/or the document content below, the user information and environment data used represents fictitious data from the Oracle sample or bulit-in schema(s), Public Documentation delivered with an Oracle database product or other training material.  Any similarity to actual environments, actual persons, living or dead, is purely coincidental and not intended in any manner.

A transaction fails with an ORA-01555 error.

ORA-01555: snapshot too old (rollback segment too small)
    Cause: rollback records needed by a reader for consistent read are overwritten by other writers

The information here is primarily intended for the old type of rollback segments with manual UNDO.
For additional information and specific information for ORA-1555 with automatic UNDO, please refer to:
Note 1307334.1 - Primary Note for ORA-1555 Errors
Note 467872.1 - TROUBLESHOOTING GUIDE (TSG) - ORA-1555
Note 269814.1 - ORA-01555 Using Automatic Undo Management - Causes and Solutions



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