ora-01559 롤백 세그먼트의 maxextents 는 2 이상입니다.

Error: ORA-01559: maximum extents for rollback segment reached.

Description

This error indicates that a rollback segment has reached its maximum number of extents as specified by the MAXEXTENTS parameter. Oracle does not allow the MAXEXTENTS value for rollback segments to be less than 2 since at least one extent is required for the rollback segment header and one or more for the actual data.

Cause

The error is typically caused by one of the following reasons:

• An attempt was made to set the MAXEXTENTS parameter of a rollback segment to a value less than 2.
• The rollback segment has automatically attempted to extend beyond the allocated MAXEXTENTS limit.

Example

An example of attempting to set an invalid MAXEXTENTS value:

ALTER ROLLBACK SEGMENT rbs1 STORAGE (MAXEXTENTS 1);

Resolution

To resolve this error, you need to:

1. Set the MAXEXTENTS parameter of the rollback segment to at least 2 or a higher value that meets the requirements of your transaction volume.
2. Consider using automatic undo management, which is recommended over manually managed rollback segments.

ALTER ROLLBACK SEGMENT rbs1 STORAGE (MAXEXTENTS 2);

Note: Always check the current value before changing the MAXEXTENTS setting. In addition, consider the overall space and design of your database to ensure optimal performance and avoid errors related to extents.

Precautions

Here are some precautions to take when dealing with this error:

• Backup the database regularly to prevent data loss in case of errors that may require significant changes to the rollback segments.
• Monitor the growth of rollback segments and adjust MAXEXTENTS appropriately with the increase in transaction load.
• Consult with a DBA before making changes to the MAXEXTENTS to understand the implications on the system.