Q
What does ORA-01555 (snapshot too old) indicate?
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A
A table is locked
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B
The redo log is full
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C
The undo data needed for read consistency has been overwritten
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D
A password has expired
Correct Answer:
C. The undo data needed for read consistency has been overwritten
Explanation:
Long-running queries fail when undo is reused. Increase UNDO_RETENTION or tune the query.