apache/shardingsphere · error · UnsupportedSQLOperationException

30001

30001

Error message

Unsupported SQL operation: %s.

What it means

UnsupportedSQLOperationException (error code 30001) thrown by DatabaseOperateProxyBackendHandlerFactory.createProxyBackendHandler when a parsed SQLStatement reaches this factory but is neither a CreateDatabaseStatement nor a DropDatabaseStatement. The factory only builds handlers for database-level CREATE/DROP operations; any other statement type is a programming or routing error at the caller.

Source

Thrown at proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/handler/database/DatabaseOperateProxyBackendHandlerFactory.java:58

     * Create new instance of database operate backend handler.
     *
     * @param sqlStatement SQL statement
     * @param connectionSession connection session
     * @return created instance
     */
    public static ProxyBackendHandler newInstance(final SQLStatement sqlStatement, final ConnectionSession connectionSession) {
        return createProxyBackendHandler(sqlStatement, connectionSession);
    }
    
    private static ProxyBackendHandler createProxyBackendHandler(final SQLStatement sqlStatement, final ConnectionSession connectionSession) {
        ContextManager contextManager = ProxyContext.getInstance().getContextManager();
        if (sqlStatement instanceof CreateDatabaseStatement) {
            return new CreateDatabaseProxyBackendHandler((CreateDatabaseStatement) sqlStatement, contextManager);
        }
        if (sqlStatement instanceof DropDatabaseStatement) {
            return new DropDatabaseProxyBackendHandler((DropDatabaseStatement) sqlStatement, contextManager, connectionSession);
        }
        throw new UnsupportedSQLOperationException(sqlStatement.getClass().getName());
    }
}

View on GitHub (pinned to e952770a21)

Solutions

1. Route only CREATE/DROP DATABASE statements to this factory; other statements belong in the regular SQL or DistSQL handler factories
2. If you added a new database-operate statement type, add an instanceof branch constructing the proper ProxyBackendHandler before the throw
3. Align frontend parser and backend-core versions so recognized statement types match

Example fix

// before
if (sqlStatement instanceof CreateDatabaseStatement) { ... }
if (sqlStatement instanceof DropDatabaseStatement) { ... }
throw new UnsupportedSQLOperationException(sqlStatement.getClass().getName());

// after (supporting a new statement type)
if (sqlStatement instanceof CreateDatabaseStatement) { ... }
if (sqlStatement instanceof DropDatabaseStatement) { ... }
if (sqlStatement instanceof AlterDatabaseStatement) {
    return new AlterDatabaseProxyBackendHandler((AlterDatabaseStatement) sqlStatement, contextManager);
}
throw new UnsupportedSQLOperationException(sqlStatement.getClass().getName());

private boolean isSupportedDatabaseOperateStatement(final SQLStatement stmt) {
    return stmt instanceof CreateDatabaseStatement || stmt instanceof DropDatabaseStatement;
}

try {
    handler = DatabaseOperateProxyBackendHandlerFactory.newInstance(stmt, connectionSession);
} catch (final UnsupportedSQLOperationException ex) {
    // statement was routed to the wrong factory; route to the standard SQL handler chain instead
}

When it happens

Trigger: Calling DatabaseOperateProxyBackendHandlerFactory.newInstance(sqlStatement, connectionSession) with a statement class outside {CreateDatabaseStatement, DropDatabaseStatement} — e.g. a new database-operate statement type added to the parser without a matching handler branch here.

Common situations: Extending the proxy with new DDL statement types and forgetting to register a handler; version skew where the parser (dialect frontend) produces statement classes newer than the backend handler factory knows; misconfigured statement classification in a custom frontend protocol.

Related errors

• 30001
• Statement is not supported by the MCP contract.
• Algorithm `%s` is unsupported to decrypt
• 40
• getUnicodeStream

AI-assisted analysis of apache/shardingsphere@e952770a21 (2026-08-14). Data as JSON: /api/errors/4870014f7e9d68fc. Report an issue: GitHub.