MySQL“;“显示表格状态”;,自动递增不正确
我在Mysql中创建了一个新表,添加了一些行,但是show tables的Auto_increment字段仍然返回NULL mysql手册说:这个字段应该返回:“下一个自动增量值” 我做错了什么 如何正确找到下一个自动增量值MySQL“;“显示表格状态”;,自动递增不正确,mysql,mysql-8.0,Mysql,Mysql 8.0,我在Mysql中创建了一个新表,添加了一些行,但是show tables的Auto_increment字段仍然返回NULL mysql手册说:这个字段应该返回:“下一个自动增量值” 我做错了什么 如何正确找到下一个自动增量值 复制步骤: create table `test` ( `id` int(5) not null auto_increment, `name` varchar(256), PRIMARY KEY(`id`) ); 然后我跑: show table stat
复制步骤:
create table `test` (
`id` int(5) not null auto_increment,
`name` varchar(256),
PRIMARY KEY(`id`)
);
然后我跑:
show table status where name like 'test';
结果:
Name, Engine, Version, ..., Auto_increment, ...
'test', 'InnoDB', '10', ..., NULL, ...
1 name1
2 name2
3 name3
'innodb_version', '8.0.12'
'protocol_version', '10'
'slave_type_conversions', ''
'tls_version', 'TLSv1,TLSv1.1,TLSv1.2'
'version', '8.0.12'
'version_comment', 'MySQL Community Server - GPL'
'version_compile_machine', 'x86_64'
'version_compile_os', 'Win64'
'version_compile_zlib', '1.2.11'
然后我跑:
insert into test values(null,'name1');
insert into test values(null,'name2');
insert into test values(null,'name3');
编辑:-其他插入语法-
insert into test (name) values('name4');
insert into test (name) values('name5');
insert into test (name) values('name6');
获取表的状态
show table status where name like 'test';
结果
Name, Engine, Version, ..., Auto_increment, ...
'test', 'InnoDB', '10', ..., NULL, ...
表中的数据
select * from test;
结果:
Name, Engine, Version, ..., Auto_increment, ...
'test', 'InnoDB', '10', ..., NULL, ...
1 name1
2 name2
3 name3
'innodb_version', '8.0.12'
'protocol_version', '10'
'slave_type_conversions', ''
'tls_version', 'TLSv1,TLSv1.1,TLSv1.2'
'version', '8.0.12'
'version_comment', 'MySQL Community Server - GPL'
'version_compile_machine', 'x86_64'
'version_compile_os', 'Win64'
'version_compile_zlib', '1.2.11'
供您参考:
SHOW VARIABLES LIKE "%version%";
结果:
Name, Engine, Version, ..., Auto_increment, ...
'test', 'InnoDB', '10', ..., NULL, ...
1 name1
2 name2
3 name3
'innodb_version', '8.0.12'
'protocol_version', '10'
'slave_type_conversions', ''
'tls_version', 'TLSv1,TLSv1.1,TLSv1.2'
'version', '8.0.12'
'version_comment', 'MySQL Community Server - GPL'
'version_compile_machine', 'x86_64'
'version_compile_os', 'Win64'
'version_compile_zlib', '1.2.11'
编辑:
自动提交:
SHOW VARIABLES LIKE "autocommit";
结果:
'autocommit', 'ON'
编辑:
一段时间后,它自动开始工作。没有明确的理由如何让它开始工作。这是一项功能。。不是虫子 表统计信息被缓存。要禁用缓存并始终使用最新版本,应将指示缓存清除持续时间的服务器变量更改为0:
SET PERSIST information_schema_stats_expiry = 0
在Mysql 8.x中,此属性的默认值已更改为86400(24小时)
例如:
SET PERSIST information_schema_stats_expiry = 86400
-- 86400 is the default value of mysql 8.x if you have never changed this you don't need to set this
show variables like 'information_schema_stats_expiry';
+---------------------------------+-------+
| Variable_name | Value |
+---------------------------------+-------+
| information_schema_stats_expiry | 86400 |
+---------------------------------+-------+
create schema mytest;
create table `test` (
`id` int(5) not null auto_increment,
`name` varchar(256),
PRIMARY KEY(`id`)
);
insert into test values(null,'name1')
insert into test values(null,'name2')
insert into test values(null,'name3')
show table status where name like 'test';
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
| Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
| test | InnoDB | 10 | Dynamic | 3 | 5461 | 16384 | 0 | 0 | 0 | 4 | 2018-10-09 15:32:15 | 2018-10-09 15:32:16 | NULL | utf8mb4_0900_ai_ci | NULL | | |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
-- The Auto_increment field is correctly set to 4.. but is now cached.
insert into test values(null,'name3');
show table status where name like 'test';
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
| Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
| test | InnoDB | 10 | Dynamic | 3 | 5461 | 16384 | 0 | 0 | 0 | 4 | 2018-10-09 15:32:15 | 2018-10-09 15:32:16 | NULL | utf8mb4_0900_ai_ci | NULL | | |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
-- The Auto_increment is still 4 (it was cached).
drop schema mytest
现在我们更改配置:
SET PERSIST information_schema_stats_expiry = 0
我们运行相同的测试:
show variables like 'information_schema_stats_expiry'
+---------------------------------+-------+
| Variable_name | Value |
+---------------------------------+-------+
| information_schema_stats_expiry | 0 |
+---------------------------------+-------+
create schema mytest;
create table `test` (
`id` int(5) not null auto_increment,
`name` varchar(256),
PRIMARY KEY(`id`)
);
insert into test values(null,'name1');
insert into test values(null,'name2');
insert into test values(null,'name3');
show table status where name like 'test';
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
| Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
| test | InnoDB | 10 | Dynamic | 3 | 5461 | 16384 | 0 | 0 | 0 | 4 | 2018-10-09 15:32:49 | 2018-10-09 15:32:49 | NULL | utf8mb4_0900_ai_ci | NULL | | |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
-- Auto_increment is 4, but the result is not cached!
insert into test values(null,'name3');
show table status where name like 'test';
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
| Name | Engine | Version | Row_format | Rows | Avg_row_length | Data_length | Max_data_length | Index_length | Data_free | Auto_increment | Create_time | Update_time | Check_time | Collation | Checksum | Create_options | Comment |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
| test | InnoDB | 10 | Dynamic | 4 | 4096 | 16384 | 0 | 0 | 0 | 5 | 2018-10-09 15:32:49 | 2018-10-09 15:32:49 | NULL | utf8mb4_0900_ai_ci | NULL | | |
+------+--------+---------+------------+------+----------------+-------------+-----------------+--------------+-----------+----------------+---------------------+---------------------+------------+--------------------+----------+----------------+---------+
-- The Auto_increment field is now 5 (a correct, not cached value)
drop schema mytest;
这可能是一个错误。您已经将id设置为
null
不知道为什么它仍然有值,请使用更为ANSI的SQL insert并使用“断开”的列名。。它在MySQL 5.7上工作,所以我假设这是一个MySQL 8.0bug@JDC:在mysql中是否设置了自动提交变量。@Suresh显示“自动提交”之类的变量-->'自动提交','打开'