YunaiV/yudao-cloud · critical · FlowableException

couldn't deduct database type from database product name '{}

Error message

couldn't deduct database type from database product name '{}'

What it means

Flowable reads DatabaseMetaData.getDatabaseProductName() and maps it to an internal databaseType via the databaseTypeMappings Properties table. If the product name (after CockroachDB special-casing) has no entry, it throws this FlowableException showing the unrecognized name.

Source

Thrown at sql/dm/flowable-patch/src/main/java/org/flowable/common/engine/impl/AbstractEngineConfiguration.java:522

            // CRDB does not expose the version through the jdbc driver, so we need to fetch it through version().
            if (PRODUCT_NAME_POSTGRES.equalsIgnoreCase(databaseProductName)) {
                try (PreparedStatement preparedStatement = connection.prepareStatement("select version() as version;");
                     ResultSet resultSet = preparedStatement.executeQuery()) {
                    String version = null;
                    if (resultSet.next()) {
                        version = resultSet.getString("version");
                    }

                    if (StringUtils.isNotEmpty(version) && version.toLowerCase().startsWith(PRODUCT_NAME_CRDB.toLowerCase())) {
                        databaseProductName = PRODUCT_NAME_CRDB;
                        logger.info("CockroachDB version '{}' detected", version);
                    }
                }
            }

            databaseType = databaseTypeMappings.getProperty(databaseProductName);
            if (databaseType == null) {
                throw new FlowableException("couldn't deduct database type from database product name '" + databaseProductName + "'");
            }
            logger.debug("using database type: {}", databaseType);

        } catch (SQLException e) {
            throw new RuntimeException("Exception while initializing Database connection", e);
        } finally {
            try {
                if (connection != null) {
                    connection.close();
                }
            } catch (SQLException e) {
                logger.error("Exception while closing the Database connection", e);
            }
        }

        // Special care for MSSQL, as it has a hard limit of 2000 params per statement (incl bulk statement).
        // Especially with executions, with 100 as default, this limit is passed.
        if (DATABASE_TYPE_MSSQL.equals(databaseType)) {

View on GitHub (pinned to 477be9dd49)

Solutions

1. Set the database type explicitly so the mapping lookup is skipped: cfg.setDatabaseType("oracle") (or the closest compatible type).
2. Add a mapping before engine build: cfg.setDatabaseTypeMappings(custom) or databaseTypeMappings.put('<product name>', 'oracle') on the configuration.
3. Patch the driver/URL so the product name matches an expected key (some DM drivers accept a compatibility flag that reports 'Oracle').
4. Verify the actual name via a quick JDBC snippet printing metaData.getDatabaseProductName().

Example fix

// before
ProcessEngineConfiguration cfg = ...; // auto-detect fails on DM DBMS

// after
ProcessEngineConfiguration cfg = ...;
cfg.setDatabaseType("oracle"); // DM is Oracle-compatible

try (Connection c = ds.getConnection()) {
    String product = c.getMetaData().getDatabaseProductName();
    String type = databaseTypeMappings.getProperty(product);
    if (type == null) type = "oracle"; // DM fallback
    cfg.setDatabaseType(type); // bypass auto-detection
}

try { engine = cfg.buildProcessEngine(); }
catch (FlowableException e) {
    if (e.getMessage().contains("couldn't deduct database type")) {
        cfg.setDatabaseType("oracle"); // retry once with explicit type
        engine = cfg.buildProcessEngine();
    } else throw e;
}

When it happens

Trigger: Connecting to a database whose product name is not a key in the built-in mappings — e.g. 'DM DBMS' from Dameng, 'OSCAR', a new Derby/H2 version string, or a proxy/wrapper driver that reports its own name. Only names like Oracle, MySQL, PostgreSQL, H2, SQL Server, DB2, etc. are mapped by default.

Common situations: Using DM (Dameng) or another national database with unpatched Flowable; a vendor-patched driver that changes DatabaseMetaData.getDatabaseProductName(); running against a database fork whose name string drifted (e.g. 'PostgreSQL-XL').

Related errors

• Error while building ibatis SqlSessionFactory: {}
• Cannot determine the Oracle database version number
• couldn't lookup datasource from {}: {}
• DataSource or JDBC properties have to be specified in a proc
• Exception while initializing Database connection

AI-assisted analysis of YunaiV/yudao-cloud@477be9dd49 (2026-08-14). Data as JSON: /api/errors/26a7b816bb4b1582. Report an issue: GitHub.