标题: ORA-54 While Alter Index Unusable Online [打印本页] 作者: 刘泽宇 时间: 2024-11-3 10:50 标题: ORA-54 While Alter Index Unusable Online 现象：
Received below error when alter an index unusable online:
alter index <Index_name> unusable online;
ORA-00054: resource busy and acquire with NOWAIT specified or timeout expired
原因：
The error is expected if DML operations for the underlying object are not completed within the specified DDL_LOCK_TIMEOUT value:
ONLINE Clause is a new enhancement introduced in 12C to make index UNUSABLE, ALTER INDEX UNUSABLE ONLINE will not impact ongoing DML. DDL operations can wait for a user configurable time period (DDL_LOCK_TIMEOUT), if underlying resource is busy, and is supported at system and session levels.
处理方法：
It executes successfully if no ongoing DML operations.