多项选择题
A user receives the following error while executing a query：
ORA01555：snapshot too old
Which two options can be the solutions to avoid such errors in future？（）
A.increase the size of redo log files
B.increase the size of the undo tablespace
C.increase the size of the Database Buffer Cache
D.increase the size of the default temporary tablespace
E.enable the retention guarantee for the undo tablespace
相关考题
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多项选择题
User SCOTT executes the following command on the EMP table but has not issued COMMIT， ROLLBACK，or any data definition language （DDL） command： SQL> SELECT job FROM emp 2 WHERE job=’CLERK’ FOR UPDATE OF empno SCOTT has opened another session to work with the database. Which three operations would wait when issued in SCOTT’s second session？（）
A.LOCK TABLE emp IN SHARE MODE;
B.LOCK TABLE emp IN EXCLUSIVE MODE;
C.DELETE FROM emp WHERE job=’MANAGER’;
D.INSERT INTO emp（empno，ename） VALUES （1289，’Dick’）;
E.SELECT job FROM emp WHERE job=’CLERK’ FOR UPDATE OF empno; -
多项选择题
WhichtwoarevalidlockinglevelsthatareusedbytransactionsinanOracledatabase？（）
A.row level
B.block level
C.object level
D.schema level
E.database level -
单项选择题
The ST_INFO master table has millions of rows that are updated very rarely. It has a STATE_CODE column that contains the value for 25 states. The table is frequently queried on the STATE_CODE column. Which type of index would you suggest to improve the query performance？（）
A.Btree
B.bitmap
C.reverse key
D.function based
