概述
对Nginx域名转发做了个压测，结果不大理想，jmeter哗哗的报错，nginx连接全是超时，tps波动特别大。如下图
tps在490的时候开始剧烈抖动
大致的错误信息如下
{
: "timestamp":"2021-09-22T07:52:22.178+0000",
: "status":500,
: "error":"Internal Server Error",
: "message":"\n### Error querying database. Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure\n\nThe last packet successfully received from the server was 10,949 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.\n### The error may exist in class path resource [mybatis/mapper/UserMapper.xml]\n### The error may involve defaultParameterMap\n### The error occurred while setting parameters\n### SQL: SELECT user_id,user_name,user_nickname,user_password,user_realname,user_gender,user_birthday,user_profile_picture_src,user_address,user_homeplace FROM user WHERE user_name = ? and user_password = ?\n### Cause: com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure\n\nThe last packet successfully received from the server was 10,949 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.\n; Communications link failure\n\nThe last packet successfully received from the server was 10,949 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure\n\nThe last packet successfully received from the server was 10,949 milliseconds ago. The last packet sent successfully to the server was 0 milliseconds ago.",
: "path":"/tmall/login/doLogin"
}
看错误信息是因为jdbc连接池异常中断导致的，检查一下连接池的配置
考虑到系统使用的人很少，几乎不会有多少jdbc并发，所以连接池的最大连接数有点高了，可能会资源浪费。改小一点再做调试
spring.datasource.druid.initial-size=3
spring.datasource.druid.min-idle=3
spring.datasource.druid.max-active=10
Tps基本保持稳定，jmeter不再报错。但是偶尔还是会有波动。
linux能看到一些错误信息，如下
The last packet successfully received from the server was 11,938 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago.; nested exception is com.mysql.jdbc.exceptions.jdbc4.CommunicationsException: Communications link failure
The last packet successfully received from the server was 11,938 milliseconds ago. The last packet sent successfully to the server was 1 milliseconds ago.] with root cause java.io.EOFException: Can not read response from server. Expected to read 4 bytes, read 0 bytes before connection was unexpectedly lost.
at com.mysql.jdbc.MysqlIO.readFully(MysqlIO.java:3014) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3472) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.mysql.jdbc.MysqlIO.reuseAndReadPacket(MysqlIO.java:3462) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3905) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2530) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2683) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2495) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.mysql.jdbc.PreparedStatement.executeInternal(PreparedStatement.java:1903) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.mysql.jdbc.PreparedStatement.execute(PreparedStatement.java:1242) ~[mysql-connector-java-5.1.47.jar:5.1.47]
at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_execute(FilterChainImpl.java:3461) ~[druid-1.1.19.jar:1.1.19]
at com.alibaba.druid.filter.FilterEventAdapter.preparedStatement_execute(FilterEventAdapter.java:440) ~[druid-1.1.19.jar:1.1.19]
at com.alibaba.druid.filter.FilterChainImpl.preparedStatement_execute(FilterChainImpl.java:3459) ~[druid-1.1.19.jar:1.1.19]
at com.alibaba.druid.proxy.jdbc.PreparedStatementProxyImpl.execute(PreparedStatementProxyImpl.java:167) ~[druid-1.1.19.jar:1.1.19]
at com.alibaba.druid.pool.DruidPooledPreparedStatement.execute(DruidPooledPreparedStatement.java:497) ~[druid-1.1.19.jar:1.1.19]
at org.apache.ibatis.executor.statement.PreparedStatementHandler.query(PreparedStatementHandler.java:64) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.executor.statement.RoutingStatementHandler.query(RoutingStatementHandler.java:79) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.executor.SimpleExecutor.doQuery(SimpleExecutor.java:63) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.executor.BaseExecutor.queryFromDatabase(BaseExecutor.java:324) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.executor.BaseExecutor.query(BaseExecutor.java:156) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:109) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.executor.CachingExecutor.query(CachingExecutor.java:83) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:147) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectList(DefaultSqlSession.java:140) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.session.defaults.DefaultSqlSession.selectOne(DefaultSqlSession.java:76) ~[mybatis-3.5.1.jar:3.5.1]
at sun.reflect.GeneratedMethodAccessor82.invoke(Unknown Source) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_241]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_241]
at org.mybatis.spring.SqlSessionTemplate\(SqlSessionInterceptor.invoke(SqlSessionTemplate.java:426) ~[mybatis-spring-2.0.2.jar:2.0.2] at com.sun.proxy.\)Proxy96.selectOne(Unknown Source) ~[?:?]
at org.mybatis.spring.SqlSessionTemplate.selectOne(SqlSessionTemplate.java:159) ~[mybatis-spring-2.0.2.jar:2.0.2]
at org.apache.ibatis.binding.MapperMethod.execute(MapperMethod.java:87) ~[mybatis-3.5.1.jar:3.5.1]
at org.apache.ibatis.binding.MapperProxy.invoke(MapperProxy.java:58) ~[mybatis-3.5.1.jar:3.5.1]
at com.sun.proxy.$Proxy104.selectByLogin(Unknown Source) ~[?:?]
at com.xq.tmall.service.impl.UserServiceImpl.login(UserServiceImpl.java:47) ~[tmall.jar:?]
at sun.reflect.GeneratedMethodAccessor81.invoke(Unknown Source) ~[?:?]
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[?:1.8.0_241]
at java.lang.reflect.Method.invoke(Method.java:498) ~[?:1.8.0_241]
调用login方法的时候，mysql的IO队列阻塞了，数据包回不来。直接检查login调用的user表，看索引。
这张表里面对username加了索引，但是没有对password加，也没对realname加。实际上登录执行的是realname字段！
下面把索引补上
再次运行，tps稳定不抖动，后端无任何错误信息
应用和数据库分离
原先那个mysql应用和项目应用是在同一台服务器上面。后期调试的时候直接把mysql应用拉到了另一台服务器上。再次执行发现tps能够稳定在到800左右，无任何异常。
