zhisheng17/flink-learning · error · RuntimeException

Unsupported command: {}

Error message

Unsupported command: {}

What it means

Planner.callCommand throws a generic RuntimeException when a SqlCommandCall parsed from the script carries a command enum value the planner's switch does not handle. Every parsed statement must map to a planner branch (callInsert, callUpdate, explain, callCreateFunction); unhandled values hit the default case. It indicates a gap between the parser's command registry and the planner's dispatch.

Source

Thrown at flink-learning-sql/flink-learning-sql-client/src/main/java/com/zhisheng/sql/planner/Planner.java:90

                break;
            case CREATE_TABLE:
            case CREATE_CATALOG:
            case USER_CATALOG:
            case CREATE_VIEW:
                callUpdate(cmdCall);
                break;
            case EXPLAIN_FOR:
                explain(cmdCall);
                break;
            case INSERT_INTO:
            case INSERT_OVERWRITE:
                callInsert(cmdCall);
                break;
            case CREATE_FUNCTION:
                callCreateFunction(cmdCall);
                break;
            default:
                throw new RuntimeException("Unsupported command: " + cmdCall.command);
        }
    }

    private void callInsert(SqlCommandParser.SqlCommandCall cmdCall) {
        String dml = cmdCall.operands[0];
        statementSet.addInsertSql(dml);
    }

    private void callSet(SqlCommandParser.SqlCommandCall cmdCall) {
        LOG.info("set:" + cmdCall.operands[0] + "=" + cmdCall.operands[1]);
        String key = cmdCall.operands[0];
        String value = cmdCall.operands[1];

        if (Constant.IDLE_STATERETENTIOO_TIME.equals(key)) {
            String unit = value.replaceAll("\\d+", "");
            String number = value.replaceAll("\\w+", "");
            UnitEnum duration = UnitEnum.valueOf(unit);
            switch (duration) {

View on GitHub (pinned to d731cee761)

Solutions

1. Remove or replace the unsupported statement in your SQL script with one the planner handles (INSERT, CREATE TABLE, CREATE FUNCTION, etc.)
2. Add a case for the missing SqlCommand in Planner.callCommand that routes it to the appropriate handler
3. Compare the SqlCommand enum's values against the switch cases in callCommand to find the unhandled command

Example fix

// before
case CREATE_FUNCTION:
    callCreateFunction(cmdCall);
    break;
default:
    throw new RuntimeException("Unsupported command: " + cmdCall.command);
// after
case CREATE_FUNCTION:
    callCreateFunction(cmdCall);
    break;
case SET:
    callSet(cmdCall);
    break;
default:
    throw new RuntimeException("Unsupported command: " + cmdCall.command);

SqlCommand cmd = cmdCall.command;
if (!EnumSet.of(INSERT_INTO, CREATE_TABLE, CREATE_FUNCTION, EXPLAIN).contains(cmd)) {
    throw new UnsupportedOperationException("Command not handled by planner: " + cmd);
}

try {
    planner.callCommand(cmdCall);
} catch (RuntimeException e) {
    LOG.error("Planner rejected command {}: {}", cmdCall.command, e.getMessage());
    throw e;
}

When it happens

Trigger: A statement parses into a SqlCommand (e.g. SET, SELECT, BEGIN/COMMIT style commands) that the Planner's switch statement in callCommand has no case for, so execution falls through to the default throw.

Common situations: SQL scripts using client-utility statements (SET, RESET, HELP, QUIT, SELECT) that the parser recognizes but this simplified planner does not dispatch; adding a new SqlCommand enum value without adding a corresponding case in callCommand.

Understand the failure class

Background: UnsupportedOperationException and "is not supported" errors: when a library deliberately refuses a call — this error's family across 30 libraries.

Related errors

• Unsupported command '{}'
• SQL parse failed: {}
• invalid elasticsearch hosts format
• invalid elasticsearch hosts format
• Unsupported client type - cannot happen

AI-assisted analysis of zhisheng17/flink-learning@d731cee761 (2026-09-06). Data as JSON: /api/errors/30795221352a764f. Report an issue: GitHub.