读undo问题

SQL> drop table test1 purge;

Table dropped.

SQL> create table test1 as select * from dba_objects where 1=2;

Table created.

SQL> insert into test1  select * from dba_objects;

74506 rows created.

SQL> insert into test1  select * from  test1;

74506 rows created.

SQL> /

149012 rows created.

SQL> /

298024 rows created.

SQL> /

596048 rows created.

SQL> /

1192096 rows created.

SQL> select segment_name,bytes/1024/1024 from dba_segments where owner='TEST' and segment_name='TEST1';

SEGMENT_NAME

--------------------------------------------------------------------------------

BYTES/1024/1024

---------------

TEST1

	      9

SQL> set linesize 200

SQL> /

SEGMENT_NAME									  BYTES/1024/1024

--------------------------------------------------------------------------------- ---------------

TEST1												9

SQL> /

SEGMENT_NAME									  BYTES/1024/1024

--------------------------------------------------------------------------------- ---------------

TEST1											       34

SQL> /

SEGMENT_NAME									  BYTES/1024/1024

--------------------------------------------------------------------------------- ---------------

TEST1											       88

SQL> /

SEGMENT_NAME									  BYTES/1024/1024

--------------------------------------------------------------------------------- ---------------

TEST1											      128

SQL> /

SEGMENT_NAME									  BYTES/1024/1024

--------------------------------------------------------------------------------- ---------------

TEST1											      152

SQL> /

SEGMENT_NAME									  BYTES/1024/1024

--------------------------------------------------------------------------------- ---------------

TEST1											      270

随着数据的插入,虽然没有提交,但是表的大小不断增大

SQL> /

       SID EVENT

---------- ----------------------------------------------------------------

	38 db file sequential read

看到了大量的db file sequential read,可以判定是读的undo块