SYS用户连接进来查询testtb的表信息，没有看到。

15:54:50 SQL> conn / as sysdba
Connected.
15:55:10 SQL> select BLOCKS,EMPTY_BLOCKS,NUM_ROWS,AVG_ROW_LEN from dba_tables where table_name='TESTTB';

    BLOCKS EMPTY_BLOCKS   NUM_ROWS AVG_ROW_LEN
---------- ------------ ---------- -----------

Elapsed: 00:00:00.03
15:55:21 SQL> show user;
USER is "SYS"

表空间所有者test01用户登录进来查询testtb表的信息，也没有看到。
15:55:30 SQL> conn test01/oracle
Connected.
15:55:38 SQL> select BLOCKS,EMPTY_BLOCKS,NUM_ROWS,AVG_ROW_LEN from dba_tables where table_name like '%TESTTB%';

    BLOCKS EMPTY_BLOCKS   NUM_ROWS AVG_ROW_LEN
---------- ------------ ---------- -----------

Elapsed: 00:00:00.15
15:56:16 SQL> select BLOCKS,EMPTY_BLOCKS,NUM_ROWS,AVG_ROW_LEN from dba_tables where table_name='TESTTB';

    BLOCKS EMPTY_BLOCKS   NUM_ROWS AVG_ROW_LEN
---------- ------------ ---------- -----------

Elapsed: 00:00:00.02
15:56:32 SQL> select BLOCKS,EMPTY_BLOCKS,NUM_ROWS,AVG_ROW_LEN from user_tables where table_name='TESTTB';

    BLOCKS EMPTY_BLOCKS   NUM_ROWS AVG_ROW_LEN
---------- ------------ ---------- -----------

Elapsed: 00:00:00.01
15:56:37 SQL> select BLOCKS,EMPTY_BLOCKS,NUM_ROWS,AVG_ROW_LEN from all_tables where table_name='TESTTB';

    BLOCKS EMPTY_BLOCKS   NUM_ROWS AVG_ROW_LEN
---------- ------------ ---------- -----------

Elapsed: 00:00:00.01

查询该表，耗时14秒，是一个空表。昨天做了插入数据操作。但由于数据量太大，取消了。
15:56:43 SQL> select * from testtb;

no rows selected

Elapsed: 00:00:14.10

查询该表结构。
15:57:05 SQL> show user;
USER is "TEST01"
15:57:08 SQL> desc testtb;
 Name                    Null?    Type
 ------------------------------- -------- -----------------
 ID                               NUMBER(38)
 SEX                              VARCHAR2(4)
 NAME                             VARCHAR2(20)

15:57:13 SQL>

为什么会这样，很郁闷，谁能帮我解释这个问题。。。。