TPS分析优化案例原创
{ : "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" }
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 failureThe 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
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！
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。
