版权声明:本文为博主原创文章,未经博主允许不得转载。 https://blog.csdn.net/xxzhaobb/article/details/82017971
-- 段延迟,创建表,并查看段
-- 默认情况下,从11.2开始,段延迟是true,
C##BB@win12c>show parameter segment
NAME TYPE VALUE
------------------------------------ ----------- ------------------------------
deferred_segment_creation boolean TRUE
rollback_segments string
transactions_per_rollback_segment integer 5
C##BB@win12c>
C##BB@orcl>CREATE TABLE part_time_employees (
empno NUMBER(8),
name VARCHAR2(30),
hourly_rate NUMBER (7,2)
)
SEGMENT CREATION DEFERRED; 2 3 4 5 6
表已创建
C##BB@orcl>
C##BB@win12c>CREATE TABLE hourly_employees (
2 empno NUMBER(8),
3 name VARCHAR2(30),
4 hourly_rate NUMBER (7,2)
5 )
6 SEGMENT CREATION IMMEDIATE
7 PARTITION BY RANGE(empno)
8 (PARTITION empno_to_100 VALUES LESS THAN (100),
9 PARTITION empno_to_200 VALUES LESS THAN (200));
表已创建。
C##BB@win12c>
C##BB@win12c>SELECT segment_name, partition_name FROM user_segments;
SEGMENT_NAME PARTITION_NAME
------------------------------ ------------------------------
HOURLY_EMPLOYEES EMPNO_TO_100
HOURLY_EMPLOYEES EMPNO_TO_200
C##BB@win12c>
C##BB@win12c>SELECT table_name, segment_created FROM user_tables;
TABLE_NAME SEGMENT_CREATED
------------------------------ ------------------------------
PART_TIME_EMPLOYEES NO
HOURLY_EMPLOYEES N/A
C##BB@win12c>
C##BB@win12c>SELECT table_name, segment_created, partition_name
2 FROM user_tab_partitions;
TABLE_NAME SEGMENT_CREATED PARTITION_NAME
------------------------------ ------------------------------ ------------------------------
HOURLY_EMPLOYEES YES EMPNO_TO_100
HOURLY_EMPLOYEES YES EMPNO_TO_200
C##BB@win12c>
插入数据
C##BB@win12c>INSERT INTO hourly_employees VALUES (99, 'FRose', 20.00);
已创建 1 行。
C##BB@win12c>INSERT INTO hourly_employees VALUES (150, 'LRose', 25.00);
已创建 1 行。
C##BB@win12c>INSERT INTO part_time_employees VALUES (50, 'KReilly', 10.00);
已创建 1 行。
C##BB@win12c>commit;
提交完成。
C##BB@win12c>
再次查询。发现插入数据后,段产生了
C##BB@win12c>SELECT table_name, segment_created FROM user_tables;
TABLE_NAME SEGMENT_CREATED
------------------------------ ------------------------------
PART_TIME_EMPLOYEES YES
HOURLY_EMPLOYEES N/A
C##BB@win12c>
end