数据库出现错误，日志里边有如下信息：

Errors in file /opt/app/oracle/admin/sc01/bdump/sc01_smon_3633.trc:
ORA-01595: error freeing extent (2) of rollback segment (5))
ORA-01594: attempt to wrap into rollback segment (5) extent (2) which is being freed
数据库版本：

Oracle9i Enterprise Edition Release 9.2.0.1.0 - 64bit Production
PL/SQL Release 9.2.0.1.0 - Production
CORE    9.2.0.1.0       Production
TNS for HPUX: Version 9.2.0.1.0 - Production
NLSRTL Version 9.2.0.1.0 - Production

百度一下，搜到一篇文章。按照文档意思，忽略它。下面是文档描述：

Subject:        With AUM Enabled ORA-01594 and ORA-01595 Found in the alert.log
          Doc ID:        280151.1        Type:        PROBLEM
          Modified Date :        21-OCT-2008        Status:        MODERATED

In this Document
  Symptoms
  Cause
  Solution
  References

This document is being delivered to you via Oracle Support's Rapid Visibility (RaV) process, and therefore has not been subject to an independent technical review.

Applies to:
Oracle Server - Enterprise Edition - Version: 9.2.0.1 to 9.2.0.7
This problem can occur on any platform.
Symptoms
The following errors are logged to alert.log:

ORA-01595: error freeing extent (2) of rollback segment (10))
ORA-01594: attempt to wrap into rollback segment (10) extent (2) which is being freed

Automatic Undo Management is enabled.
Cause

The error is signaled because smon is shrinking a rollback segment and this fails because we need an extent to store some rollback information. This is a failure message for the shrinking. Subsequently smon would succeed in doing that.
Solution
Ignore these error messages.
Normally adding more undo space should solve the problem.

This error message logging is fixed in 10g.
References