单选题What should you look at first to compute the number of undo blocks written per second to disk？ （）A V$UNDOSTATB V$TRANSACTIONC V$ROLLSTATD DBA_UNDO_EXTENTSE DBA_ROLLBACK_SEGS
题目
单选题
What should you look at first to compute the number of undo blocks written per second to disk？ （）
A
V$UNDOSTAT
B
V$TRANSACTION
C
V$ROLLSTAT
D
DBA_UNDO_EXTENTS
E
DBA_ROLLBACK_SEGS