apache/dolphinscheduler · error · RegistryException

key: not exist

Error message

key:  not exist

What it means

Thrown by JdbcRegistry.get when the queried key has no row in the registry database. The JDBC registry stores registry data in DB tables; unlike ZooKeeper, a missing key is surfaced as a RegistryException rather than a null return, so callers must treat absence as exceptional.

Source

Thrown at dolphinscheduler-registry/dolphinscheduler-registry-plugins/dolphinscheduler-registry-jdbc/src/main/java/org/apache/dolphinscheduler/plugin/registry/jdbc/JdbcRegistry.java:134

            public void onDisConnected() {
                listener.onUpdate(ConnectionState.DISCONNECTED);
            }

            @Override
            public void onReconnected() {
                listener.onUpdate(ConnectionState.RECONNECTED);
            }
        });
    }

    @Override
    public String get(String key) {
        try {
            // get the key value
            // Directly get from the db?
            Optional<JdbcRegistryDataDTO> jdbcRegistryDataOptional = jdbcRegistryClient.getJdbcRegistryDataByKey(key);
            if (!jdbcRegistryDataOptional.isPresent()) {
                throw new RegistryException("key: " + key + " not exist");
            }
            return jdbcRegistryDataOptional.get().getDataValue();
        } catch (RegistryException registryException) {
            throw registryException;
        } catch (Exception e) {
            throw new RegistryException(String.format("Get key: %s error", key), e);
        }
    }

    @Override
    public void put(String key, String value, boolean deleteOnDisconnect) {
        try {
            DataType dataType = deleteOnDisconnect ? DataType.EPHEMERAL : DataType.PERSISTENT;
            jdbcRegistryClient.putJdbcRegistryData(key, value, dataType);
        } catch (Exception ex) {
            throw new RegistryException(String.format("put key:%s, value:%s error", key, value), ex);
        }
    }

View on GitHub (pinned to 02eac45a1b)

Solutions

  1. Check key existence with registry.exists(key) before calling get
  2. Verify the key string matches what was written by put (path prefix, no typos, trailing-slash conventions)
  3. Re-put or recreate the expected registry data if it should exist
  4. Wrap get in try-catch for RegistryException and fall back to a default or re-lookup

Example fix

// before
String value = registry.get(key);
// after
if (registry.exists(key)) {
    String value = registry.get(key);
} else {
    // handle missing key
}
Defensive patterns

Strategy: validation

Validate before calling

if (!registry.exists(key)) { throw new IllegalStateException("registry key missing: " + key); }

Try / catch

try { value = registry.get(key); } catch (RegistryException e) { if (e.getMessage().contains("not exist")) { /* handle absence */ } else { throw e; } }

Prevention

When it happens

Trigger: Calling registry.get(path) for a path that was never put, was already deleted, or whose ephemeral node disappeared when the owning session disconnected.

Common situations: A master/worker looks up a task or process path after its owner died and cleanup removed the ephemeral key; a typo or stale prefix in the constructed key; racing another component's delete.

Understand the failure class

Background: Record Not Found Errors: "not found", RecordNotFound, and "was not found" — what they mean and how to fix them — this error's family across 28 libraries.

Related errors

AI-assisted analysis of apache/dolphinscheduler@02eac45a1b (2026-09-06). Data as JSON: /api/errors/0d03a78af9c37df0. Report an issue: GitHub.