1.数据库问题
1.1数据库磁盘满了
mysql57表现1:
插入数据或者更新数据可能报错
The table 'xxx' is full"
报错示例:
{
"timestamp": 1706766474768,
"status": 500,
"error": "Internal Server Error",
"exception": "org.springframework.jdbc.UncategorizedSQLException",
"message": "\r\n### Error updating database. Cause: java.sql.SQLException: The table 'sys_dict' is full\r\n### The error may exist in file [D:\\my_projects\\spring-boot-mybatis\\target\\classes\\mapping\\SysDictMapper.xml]\r\n### The error may involve defaultParameterMap\r\n### The error occurred while setting parameters\r\n### SQL: insert into sys_dict ( id, code, label, category, category_id, parent_id, seq, create_time ) values ( ?, ?, ?, ?, ?, ?, ?, ? )\r\n### Cause: java.sql.SQLException: The table 'sys_dict' is full\n; uncategorized SQLException for SQL []; SQL state [HY000]; error code [1114]; The table 'sys_dict' is full; nested exception is java.sql.SQLException: The table 'sys_dict' is full",
"path": "/country/save"
}
mysql57表现2:
No space left on device
特别说明:此处是数据库服务器没有空间了.不是应用所在服务器没有空间了
示例:
Error writing file '/tmp/MYUJq063' (Errcode: 28 - No space left on device)
mysql57表现3:
猜测是由于硬盘满,数据无法插入
Lock wait timeout exceeded; try restarting transaction
1.2.连接数不够
Too many connections
报错示例:
{
"timestamp": 1706769059175,
"status": 500,
"error": "Internal Server Error",
"exception": "org.mybatis.spring.MyBatisSystemException",
"message": "nested exception is org.apache.ibatis.exceptions.PersistenceException: \r\n### Error updating database. Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: \"Too many connections\"\r\n### The error may exist in file [D:\\my_projects\\spring-boot-mybatis\\target\\classes\\mapping\\SysDictMapper.xml]\r\n### The error may involve pers.wwz.study.country.mapper.SysDictMapper.update\r\n### The error occurred while executing an update\r\n### Cause: org.springframework.jdbc.CannotGetJdbcConnectionException: Could not get JDBC Connection; nested exception is com.mysql.jdbc.exceptions.jdbc4.MySQLNonTransientConnectionException: Data source rejected establishment of connection, message from server: \"Too many connections\"",
"path": "/country/update"
}
1.3使用SSL报错
No appropriate protocol (protocol is disabled or cipher suites are inappropriate)
解决方式1:增加连接参数
示例:jdbc:mysql://192.168.168.113:3306/mybatisplus?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC&useSSL=false解决方式2:降低jdk版本
jdk1.8_181可以
解决方式3:修改jdk配置
修改jdk目录\jre\lib\security\java.security
删除掉SSLv3, TLSv1, TLSv1.1
默认配置示例
jdk.tls.disabledAlgorithms=SSLv3, TLSv1, TLSv1.1, DTLSv1.0, RC4, DES, \ MD5withRSA, DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \ ECDH修改后配置示例:
jdk.tls.disabledAlgorithms=DTLSv1.0, RC4, DES, \ MD5withRSA, DH keySize < 1024, EC keySize < 224, 3DES_EDE_CBC, anon, NULL, \ ECDH1.4账户或者密码错误
Access denied for user 'xxxxx'@'xxx' (using password: YES)
解决方案:
修改为正确的账户和密码
1.5连接不上
com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet sent successfully to the server was 0 milliseconds ago. The driver has not received any packets from the server.
原因:
连接不上数据库,可能数据库挂了或者网络不通或者
解决方案:
启动或者重启数据库
保证调用端和数据库网络畅通
1.6查询报错Duplicate entry
示例:
sql:
select
XXX ,
count(*) as count
from
table_xxx
group by XXX
报错:
Duplicate entry 'XXXXXXX' for key '<group_key>'
原因:
临时表空间不够
解决方案:
增大临时表空间
/etc/my.cnf增加如下内容
#大小(字节) set tmp_table_size=100*1024*1024; set max_heap_table_size=100*1024*1024;
或者
tmp_table_size = 1024M
max_heap_table_size = 1024M3.数据库设置
如不特别说明,配置都是在[mysqld]下添加
3.1查询/设置最大连接数
3.1.1查询最大连接数
show variables like '%max_connections%';3.1.2设置最大连接数
vim /etc/my.cnf
添加
max_connections=10243.2查询连接数
#连接数
方式1:
show status like 'Threads_connected';方式2:
SELECT count(*) AS connection_count FROM information_schema.processlist;存疑??
此处如果navicat已经连接了,查询连接数navicat也能查到占用一个连接,
但是使用程序去创建连接,还是能创建连接数=设置的最大连接数,navicat占用的连接在程序中好像没有被占用一样
程序创建连接代码
String url = "jdbc:mysql://192.168.168.113:3306/mybatisplus?useUnicode=true&characterEncoding=utf-8&useSSL=true&serverTimezone=UTC&useSSL=false"; String username = "root"; String password = "King@wwz1"; try { DriverManager.getConnection(url, username, password); log.info("创建连接成功:{}",i); //可以根据需要创建更多的连接 } catch (SQLException e) { e.printStackTrace(); }3.3查询/设置超时
3.3.1查询超时配置
show global variables like '%wait_timeout';结果示例:
3.3.2设置超时
vim /etc/my.cnf
添加如下内容:
innodb_lock_wait_timeout=360000
lock_wait_timeout=360000
wait_timeout=3600003.4 the table xxx is full
内存表的大小超过了规定的范围
MySQL出现"the table is full"的问题,一般有两个原因:数据表设置太小或者服务器空间满了
3.4.1.需要加大数据表大小
解决方案
vi /etc/my.cnf
需要修改MySQL的配置文件my.cnf，在[mysqld]下添加/修改两行：
tmp_table_size = 1024Mmax_heap_table_size = 1024M系统默认是16M，修改完后重启mySQL
3.4.2.服务器硬盘空间满了
清理垃圾/无用数据即可
磁盘扩容
3.5忽略大小写
vi /etc/my.cnf
增加如下内容
lower_case_table_names=1
