Java connection using MariaDB 2.4.1 JDBC driver fails to load server variables

[marcel-dias]

Hey,

I'm trying to connect to Admin interface using Java MariaDB JDBC driver.

it fails to load the server variables as the variables had changed from the fix in #743

ProxySQL version: 2.0.3 in docker proxysql/proxysql:2.0.3
MariaDB JDBC version: 2.4.1

The exception is

java.sql.SQLNonTransientConnectionException: could not load system variables
	at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:240)
	at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.getException(ExceptionMapper.java:171)
	at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1128)
	at org.mariadb.jdbc.internal.util.Utils.retrieveProxy(Utils.java:560)
	at org.mariadb.jdbc.MariaDbConnection.newConnection(MariaDbConnection.java:174)
	at org.mariadb.jdbc.Driver.connect(Driver.java:92)
Caused by: java.sql.SQLNonTransientConnectionException: could not load system variables
	at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:240)
	at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.connException(ExceptionMapper.java:101)
	at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.requestSessionDataWithShow(AbstractConnectProtocol.java:628)
	at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.additionalData(AbstractConnectProtocol.java:641)
	at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connect(AbstractConnectProtocol.java:450)
	at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.connectWithoutProxy(AbstractConnectProtocol.java:1124)
	... 5 more
Caused by: java.sql.SQLNonTransientConnectionException: could not load system variables. socket connected: true
	at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.get(ExceptionMapper.java:240)
	at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.connException(ExceptionMapper.java:101)
	at org.mariadb.jdbc.internal.util.exceptions.ExceptionMapper.connException(ExceptionMapper.java:97)
	at org.mariadb.jdbc.internal.protocol.AbstractConnectProtocol.requestSessionDataWithShow(AbstractConnectProtocol.java:622)
	... 8 more

Debugging the driver I found the sql it executes to retrieve the server variables:

SHOW VARIABLES WHERE Variable_name in ('max_allowed_packet','system_time_zone','time_zone','auto_increment_increment');

And this the ProxySQL Admin interface return nothing to this query

> SHOW VARIABLES WHERE Variable_name in ('max_allowed_packet','system_time_zone','time_zone','auto_increment_increment');
Empty set (0.01 sec)

Could you implement a return for this query ?

Thank you!

[renecannao]

Fixed in 2.0.4