ORA-01555: snapshot too old: rollback segment number string with name “string” too small

I will explain how to solve ORA-01555: snapshot too old: rollback segment number string with name “string” too small error.

 

ORA-01555: snapshot too old

Details of error are as follows.

ORA-01555: snapshot too old: rollback segment number string with name "string" too small

Cause: rollback records needed by a reader for consistent read are overwritten by other writers
Action: If in Automatic Undo Management mode, increase undo_retention setting. Otherwise, use larger rollback segments

 

 

 

ORA-01555: snapshot too old: rollback segment number string with name “string” too small

 

Undo_retention

To solve this problem, increase the undo_retention as follows.

 

SQL> show parameter undo

NAME              TYPE               VALUE
------------------------------------ ----------- 
undo_management   string             AUTO
undo_retention    integer            900
undo_tablespace

 

SQL> alter system set undo_retention=9000 scope=both sid='*';

System altered.

 

 

Undo Tablespace in Oracle

If you have more capacity on Undo Tablespace, you can set undo_retention more than 9000.

Or add datafile if there are no space on Undo Tablespace, then add datafile to Undo tablespace as follows.

 

ALTER TABLESPACE UNDOTBS1 ADD DATAFILE '+DATA' SIZE 100M AUTOEXTEND ON NEXT 1G MAXSIZE UNLIMITED;

 

 

Now problem has been solved.

 

 

 

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About Mehmet Salih Deveci

I am Founder of SysDBASoft IT and IT Tutorial and Certified Expert about Oracle & SQL Server database, Goldengate, Exadata Machine, Oracle Database Appliance administrator with 10+years experience.I have OCA, OCP, OCE RAC Expert Certificates I have worked 100+ Banking, Insurance, Finance, Telco and etc. clients as a Consultant, Insource or Outsource.I have done 200+ Operations in this clients such as Exadata Installation & PoC & Migration & Upgrade, Oracle & SQL Server Database Upgrade, Oracle RAC Installation, SQL Server AlwaysOn Installation, Database Migration, Disaster Recovery, Backup Restore, Performance Tuning, Periodic Healthchecks.I have done 2000+ Table replication with Goldengate or SQL Server Replication tool for DWH Databases in many clients.If you need Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS Consultancy and Training you can send my email adress [email protected].-                                                                                                                                                                                                                                                 -Oracle DBA, SQL Server DBA, APPS DBA,  Exadata, Goldengate, EBS ve linux Danışmanlık ve Eğitim için  [email protected] a mail atabilirsiniz.

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