t8y2/dbx · error

unsupported IoTDB SQL dialect: %s

Error message

unsupported IoTDB SQL dialect: %s

What it means

parseConnectionConfig reads the sql_dialect (or dialect) query parameter, lowercases it, and only accepts client.TreeSqlDialect (tree) or client.TableSqlDialect (table). Any other value aborts connection setup with 'unsupported IoTDB SQL dialect: %s'.

Source

Thrown at agents/drivers/iotdb/driver.go:160

		}
		query = parsed.Query()
	}
	if raw := strings.TrimSpace(params.URLParams); raw != "" {
		values, err := url.ParseQuery(strings.TrimPrefix(raw, "?"))
		if err != nil {
			return connectionConfig{}, fmt.Errorf("parse IoTDB URL parameters: %w", err)
		}
		for key, entries := range values {
			query[key] = entries
		}
	}

	if dialect := strings.ToLower(strings.TrimSpace(firstQueryValue(query, "sql_dialect", "dialect"))); dialect != "" {
		switch dialect {
		case client.TreeSqlDialect, client.TableSqlDialect:
			config.Dialect = dialect
		default:
			return connectionConfig{}, fmt.Errorf("unsupported IoTDB SQL dialect: %s", dialect)
		}
	}
	if database := strings.TrimSpace(firstQueryValue(query, "database", "db")); database != "" {
		config.Database = database
	}
	if value := firstQueryValue(query, "fetch_size", "fetchSize"); value != "" {
		parsed, err := positiveInt(value, "fetch_size")
		if err != nil {
			return connectionConfig{}, err
		}
		config.FetchSize = int32(parsed)
	}
	if value := firstQueryValue(query, "time_zone", "timezone", "zone_id"); value != "" {
		config.TimeZone = value
	}
	if value := firstQueryValue(query, "connect_retry_max", "connectRetryMax"); value != "" {
		parsed, err := positiveInt(value, "connect_retry_max")
		if err != nil {

View on GitHub (pinned to c0390bff16)

Solutions

1. Use exactly 'tree' or 'table' (case-insensitive) as the sql_dialect/dialect value.
2. Remove the dialect parameter to fall back to the default tree dialect.
3. Verify your IoTDB server version supports the chosen dialect (table model requires 2.x).
4. Compare against the client constants client.TreeSqlDialect / client.TableSqlDialect.

Example fix

// before
"iotdb://root:root@127.0.0.1:6667?sql_dialect=treemodel"
// after
"iotdb://root:root@127.0.0.1:6667?sql_dialect=table"

func validDialect(params connectParams) error {
    for _, v := range []string{params.URLParams} {
        q, err := url.ParseQuery(strings.TrimPrefix(v, "?"))
        if err != nil {
            continue
        }
        for _, key := range []string{"sql_dialect", "dialect"} {
            if d := strings.ToLower(strings.TrimSpace(q.Get(key))); d != "" && d != "tree" && d != "table" {
                return fmt.Errorf("dialect %q must be tree or table", d)
            }
        }
    }
    return nil
}

_, err := newServer(params)
if err != nil && strings.Contains(err.Error(), "unsupported IoTDB SQL dialect") {
    params.URLParams = stripParam(params.URLParams, "sql_dialect") // fall back to default tree dialect
    _, err = newServer(params)
}

When it happens

Trigger: Passing sql_dialect=tree_model, dialect=TREE-MODEL, dialect=relational, or any typo'd/unknown value in the connection string query or URLParams.

Common situations: Users coming from JDBC docs write dialect values the IoTDB Go client doesn't recognize; server versions with different dialect naming; users assume the value matches the server-side config property name.

Related errors

• Hive host is required
• Hive endpoint is empty
• Hive JWT authentication requires jwt or the JWT environment
• Hive delegation token authentication requires delegationToke
• ZooKeeper server list is empty

AI-assisted analysis of t8y2/dbx@c0390bff16 (2026-09-05). Data as JSON: /api/errors/e41b8e27222e593b. Report an issue: GitHub.