apache/shardingsphere · warning · UnsupportedVariableException

12010

12010

Error message

Can not support variable '%s'.

What it means

UnsupportedVariableException (error code 12010) thrown by ShowDistVariableExecutor.checkVariableName while handling SHOW DIST VARIABLE. The executor supports exactly one variable, CACHED_CONNECTIONS: the name must parse via DistSQLVariable.valueOf(...) AND equal CACHED_CONNECTIONS. An unknown name (IllegalArgumentException from valueOf) or a known-but-unsupported enum constant both raise this exception.

Source

Thrown at proxy/backend/core/src/main/java/org/apache/shardingsphere/proxy/backend/handler/distsql/ral/queryable/variable/ShowDistVariableExecutor.java:91

    private boolean isTemporaryConfigurationKey(final String variableName) {
        return TemporaryConfigurationPropertyKey.getKeyNames().contains(variableName);
    }
    
    private String getTemporaryConfigurationValue(final ShardingSphereMetaData metaData, final String variableName) {
        return getStringResult(metaData.getTemporaryProps().getValue(TemporaryConfigurationPropertyKey.valueOf(variableName)));
    }
    
    private String getConnectionSize(final String variableName) {
        checkVariableName(variableName);
        return String.valueOf(connectionContext.getConnectionSize());
    }
    
    private void checkVariableName(final String variableName) {
        DistSQLVariable distSQLVariable;
        try {
            distSQLVariable = DistSQLVariable.valueOf(variableName.toUpperCase());
        } catch (final IllegalArgumentException ignored) {
            throw new UnsupportedVariableException(variableName);
        }
        ShardingSpherePreconditions.checkState(DistSQLVariable.CACHED_CONNECTIONS == distSQLVariable, () -> new UnsupportedVariableException(variableName));
    }
    
    private String getStringResult(final Object value) {
        if (null == value) {
            return "";
        }
        return value instanceof TypedSPI ? ((TypedSPI) value).getType().toString() : value.toString();
    }
    
    @Override
    public Class<ShowDistVariableStatement> getType() {
        return ShowDistVariableStatement.class;
    }
}

View on GitHub (pinned to e952770a21)

Solutions

1. Use SHOW DIST VARIABLE WHERE NAME = 'CACHED_CONNECTIONS' — the only supported show target
2. To inspect configuration properties, use SHOW PROPERTIES (proxy props) instead of SHOW DIST VARIABLE
3. Check the variable name spelling and the version's DistSQL reference for which variables each command supports

Example fix

-- before
SHOW DIST VARIABLE WHERE NAME = 'max_connections';

-- after
SHOW DIST VARIABLE WHERE NAME = 'CACHED_CONNECTIONS';

private static final Set<String> SHOWABLE_DIST_VARIABLES = Set.of("CACHED_CONNECTIONS");

public void showDistVariable(final String name) {
    if (!SHOWABLE_DIST_VARIABLES.contains(name.toUpperCase())) {
        throw new IllegalArgumentException("Only CACHED_CONNECTIONS is showable; use SHOW PROPERTIES for props");
    }
    // proceed with SHOW DIST VARIABLE WHERE NAME = name
}

When it happens

Trigger: Running SHOW DIST VARIABLE WHERE NAME = '<x>' where <x> is not CACHED_CONNECTIONS — either not a DistSQLVariable constant at all, or a valid DistSQLVariable constant other than CACHED_CONNECTIONS.

Common situations: Users assuming all SET DIST VARIABLE names are showable (e.g. SHOW DIST VARIABLE WHERE NAME = 'max-connections-size-per-query'); typos in the variable name; new DistSQLVariable enum constants added for SET but not yet supported by SHOW.

Related errors

• 12010
• 12011
• Either key generator name or algorithm segment must be provi
• 1
• 0

AI-assisted analysis of apache/shardingsphere@e952770a21 (2026-08-14). Data as JSON: /api/errors/4022af22cefcc879. Report an issue: GitHub.