java.sql.SQLException: Unknown system variable ‘query_cache_size‘

spencer_tseng2026-03-28 19:45

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Caused by: java.sql.SQLException: Unknown system variable 'query_cache_size'
	at com.mysql.jdbc.SQLError.createSQLException(SQLError.java:957)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3878)
	at com.mysql.jdbc.MysqlIO.checkErrorPacket(MysqlIO.java:3814)
	at com.mysql.jdbc.MysqlIO.sendCommand(MysqlIO.java:2478)
	at com.mysql.jdbc.MysqlIO.sqlQueryDirect(MysqlIO.java:2625)
	at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2547)
	at com.mysql.jdbc.ConnectionImpl.execSQL(ConnectionImpl.java:2505)
	at com.mysql.jdbc.StatementImpl.executeQuery(StatementImpl.java:1370)
	at com.mysql.jdbc.ConnectionImpl.loadServerVariables(ConnectionImpl.java:3862)
	at com.mysql.jdbc.ConnectionImpl.initializePropsFromServer(ConnectionImpl.java:3290)
	at com.mysql.jdbc.ConnectionImpl.connectWithRetries(ConnectionImpl.java:2128)
	... 37 more

query_cache_size 是 MySQL 5.7 专用 的系统变量，MySQL 8.0+ 已经删掉了这个变量，

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      <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.22</version>
        </dependency>