apache/seatunnel · error · DebeziumException

Timed out after <actualSeconds> seconds while waiting to con

Error message

Timed out after <actualSeconds> seconds while waiting to connect to MySQL at <hostname>:<port> with user '<username>'

What it means

The streaming source executes a JDBC connect to MySQL inside a loop that is expected to abort via InterruptedIOException/timeout when the configured connect timeout elapses. To distinguish a genuine network timeout from a too-short timeout or an interrupted connect, it measures elapsed wall-clock time: if the exception arrived only after >=90% of the timeout had really passed, it concludes the server was actually unreachable and throws this DebeziumException naming host, port, user, and measured seconds.

Source

Thrown at seatunnel-connectors-v2/connector-cdc/connector-cdc-mysql/src/main/java/io/debezium/connector/mysql/MySqlStreamingChangeEventSource.java:1220

                            for (Thread t : binaryLogClientThreads.values()) {
                                if (t.getName().startsWith(KEEPALIVE_THREAD_NAME) && t.isAlive()) {
                                    LOGGER.info("Keepalive thread is running");
                                    keepAliveThreadRunning = true;
                                }
                            }
                            metronome.pause();
                        }
                    }
                } catch (TimeoutException e) {
                    // If the client thread is interrupted *before* the client could connect, the
                    // client throws a timeout exception
                    // The only way we can distinguish this is if we get the timeout exception
                    // before the specified timeout has
                    // elapsed, so we simply check this (within 10%) ...
                    long duration = clock.currentTimeInMillis() - started;
                    if (duration > (0.9 * timeout)) {
                        double actualSeconds = TimeUnit.MILLISECONDS.toSeconds(duration);
                        throw new DebeziumException(
                                "Timed out after "
                                        + actualSeconds
                                        + " seconds while waiting to connect to MySQL at "
                                        + connectorConfig.hostname()
                                        + ":"
                                        + connectorConfig.port()
                                        + " with user '"
                                        + connectorConfig.username()
                                        + "'",
                                e);
                    }
                    // Otherwise, we were told to shutdown, so we don't care about the timeout
                    // exception
                } catch (AuthenticationException e) {
                    throw new DebeziumException(
                            "Failed to authenticate to the MySQL database at "
                                    + connectorConfig.hostname()
                                    + ":"

View on GitHub (pinned to cf67b549a7)

Solutions

1. Verify network reachability from the connector host: `mysql -h <hostname> -P <port> -u <username> -p` or `nc -vz <hostname> <port>`.
2. Increase the connect timeout option (e.g. `database.connection.timeout` / serverTimezone-compatible JDBC connectTimeout in the connector config) if the server is merely slow to accept connections.
3. Check MySQL server state: is it running, is `max_connections` exhausted, are there firewall/security-group rules allowing the connector's IP?
4. Fix hostname resolution (use the correct service DNS/IP; replace 'localhost' with the MySQL container/service name in containerized deployments).
5. Confirm the account exists and is allowed from the connector's source host (`SHOW GRANTS FOR 'user'@'host'`) — though a plain auth refusal usually surfaces as a different error.

Example fix

// before: hostname unreachable from inside the job container
url = "jdbc:mysql://localhost:3306/orders"

// after: use the service-resolvable host and a longer timeout
url = "jdbc:mysql://mysql.database.svc.cluster.local:3306/orders?connectTimeout=60000"

// preflight check before starting the streaming source
if (!pingMysql(host, port, timeoutMillis)) {
  throw new IllegalStateException("Cannot reach MySQL at " + host + ":" + port + " — fix network/credentials first");
}

try {
  startStreamingSource(config);
} catch (DebeziumException e) {
  if (e.getMessage().startsWith("Timed out after") && e.getMessage().contains("waiting to connect to MySQL")) {
    retryWithBackoff(() -> startStreamingSource(config), 3);
  } else throw e;
}

When it happens

Trigger: JDBC connection attempts to connectorConfig.hostname():port keep failing/timing out until the cumulative elapsed time exceeds 0.9 * the configured connect timeout (database.connection.timeout / connection.timeout.ms), with user <username>; thrown from the MySqlStreamingChangeEventSource constructor.

Common situations: MySQL host unreachable or DNS misconfigured; firewall/security group blocking 3306; MySQL max_connections exhausted or server overloaded; wrong port or VPC/network peering missing; user account or host grants fine but network blackhole causes silent drop; containerized setups using 'localhost' from inside another container.

Understand the failure class

• Timeouts: ETIMEDOUT, deadlines, and hung requests — what actually expires when a request times out.

Related errors

• Unable to connect to the MySQL database at <hostname>:<port>
• Error reading MySQL variables: ${e.getMessage()}
• Read the binlog offset error
• Failed to get the JDBC source connection from the current st
• CREATE_ACTIVEMQ_CLIENT_FAILED

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/e6fe678997a76a62. Report an issue: GitHub.