The MySQL database is upgraded from 5.5.25 to 8.0.12 encountered several problems, recorded as follows:
After the database is installed, import the original data, start tomcat, error unable to load authentication caching_sha2_plugin, the solution is as follows:
ALTER USER 'root' @ 'localhost ' IDENTIFIED BY 'password' PASSWORD EXPIRE NEVER; # modify the encryption rule
'root' @ 'localhost' IDENTIFIED WITH mysql_native_password BY 'password' ALTER USER; # update about the user's password
FLUSH PRIVILEGES; # refresh permission
Internet also has said that by modifying my.ini, adding
[mysqld]
default_authentication_plugin=mysql_native_password
After my test, unsuccessful, I do not know why.
https://dev.mysql.com/doc/connector-j/8.0/en/connector-j-versions.html
| Connector/J version | JDBC version | MySQL Server version | JRE Supported | jDK Required for Compilation | Status |
| 8.0 | 4.2 | 5.6, 5.7, 8.0 | 1.8.x | 1.8.x | General availability. Recommended version. |
| 5.1 | 3.0, 4.0, 4.1, 4.2 | 5.6*, 5.7*, 8.0* | 1.5.x, 1.6.x, 1.7.x, 1.8.x* | 1.5.x and 1.8.x | General availability |
The figure shows more than 8.0 connector drive requires JDK1.8 support, 5.1.x version of the driver also supports 8.0. * Mysql, and then download a newer mysql-connector-java-5.1.46 (originally 5.1.21 ), tomcat start again, without being given!
When the project is running for some time, another error:
Expression #1 of SELECT list is not in GROUP BY clause and contains nonaggre
Online search a bit, meaning open ONLY_FULL_GROUP_BY SQL mode by default after the release of 5.7, can cause this problem, modify the my.ini, adding
[mysqld]
sql_mode=STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
That is, remove sql_mode in ONLY_FULL_GROUP_BY, and then restart mysql, restart TOMCAT, normal operation of the project.
Online said through set @@ sql_mode = 'STRICT_TRANS_TABLES, NO_ZERO_IN_DATE, NO_ZERO_DATE, ERROR_FOR_DIVISION_BY_ZERO, NO_AUTO_CREATE_USER, NO_ENGINE_SUBSTITUTION' modify global settings, I tested and can not succeed, some say global setting is only effective on the later of the new database. I did not verify. There is to know, please leave a message!
Conclusion is: a production environment, do not easily change the version!