OCP-1Z0-052-V8.02-1题

1. View the Exhibit and examine the attributes of an undo tablespace.

In an OLTP system, the user SCOTT has started a query on a large table in the peak transactional hour

that performs bulk inserts. The query runs for more than 15 minutes and then SCOTT receives the

following error:

ORA-01555: snapshot too old

What could be the reason for this error?

A.The query is unable to get a read-consistent image.

B.There is not enough space in Flash Recovery Area.

C.There is not enough free space in the flashback archive.

D.The query is unable to place data blocks in undo tablespace

Answer: A

答案解析：

参考：管理还原数据：http://blog.csdn.net/rlhua/article/details/12259555

“快照太旧”错误是因为没有足够的还原数据来实现读取一致性。所以选A。

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