MySQL5.6开始可以使用独立表空间,innodb_file_per_table=1
MySQL5.6开始可以使用独立表空间:
MySQL5.6
innodb_file_per_table=1 #使用独立表空间,动态参数。(5.6默认OFF,5.7默认ON)
1、drop/truncate table方式操作表空间能自动回收(磁盘空间)
1)、创建procedure,循环insert一定量数据
##use test
##drop procedure pro1;
DELIMITER //
create procedure pro1()
begin
declare i int;
set i=1;
while i<100000 do
insert into test.cc(id,name) values(i, "aa");
set i=i+1;
end while;
end;//
2)、调用procedure :
mysql> call pro1();
3)、查看表大小、数据量:
select table_name, (data_length+index_length)/1024/1024 as total_mb, table_rows
from information_schema.tables where table_schema='test' and table_name='CC';
+------------+------------+------------+
| table_name | total_mb | table_rows |
+------------+------------+------------+
| cc | 3.51562500 | 100246 |
+------------+------------+------------+
1 row in set (0.31 sec)
4)、truncate清表:
mysql> truncate table test.cc;
Query OK, 0 rows affected (0.73 sec)
5)、再次查看表空间已经回收:
cc.ibd 由 11264KB 回收到96KB 。
mysql> select table_name, (data_length+index_length)/1024/1024 as total_mb, table_rows
-> from information_schema.tables where table_schema='test' and table_name='CC';
+------------+------------+------------+
| table_name | total_mb | table_rows |
+------------+------------+------------+
| cc | 0.01562500 | 0 |
+------------+------------+------------+
1 row in set (0.00 sec)
mysql>
mysql> select version();
+------------+
| version() |
+------------+
| 5.7.11-log |
+------------+
1 row in set (0.08 sec)
mysql>
注:drop table test.cc ; 物理文件cc.ibd也会同时被删除。
2、独立表空间下,可以自定义表的存储位置,(有时将部分热表放在不同的磁盘可有效地提升IO性能)
create table test(id int) data directory='c:/software';
create table test1(id int,name varchar(20),primary key (id)) data directory='c:/software';
3、独立表空间下,可以回收表空间碎片(比如一个非常大的delete操作之后释放的空间)
1)创建测试表
DELIMITER //
create procedure pro_test1()
begin
declare i int;
set i=1;
while i<10000 do
insert into test.test1(id,name) values(i, "aa");
set i=i+1;
end while;
end;//
##call pro_test1();
表大小:test1.ibd 368KB
2)delete后表大小:
2)delete后表大小:
mysql> delete from test1;
test1.ibd 384KB
3)回收表空间
3)回收表空间
mysql> alter table test1 engine=innodb;
test1.ibd 96KB
mysql> select table_name, (data_length+index_length)/1024/1024 as total_mb, table_rows
from information_schema.tables where table_schema='test' and table_name='TEST1';
+------------+------------+------------+
| table_name | total_mb | table_rows |
+------------+------------+------------+
| test1 | 0.01562500 | 0 |
+------------+------------+------------+
1 row in set (0.00 sec)
| table_name | total_mb | table_rows |
+------------+------------+------------+
| test1 | 0.01562500 | 0 |
+------------+------------+------------+
1 row in set (0.00 sec)
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