apache/seatunnel · error · IOException

Exceeded maxBatchSendAttempts=${maxBatchSendAttempts} withou

Error message

Exceeded maxBatchSendAttempts=${maxBatchSendAttempts} without RECEIVED for batch ${batchId}

What it means

sendBatchUntilReceived retries a batch only up to config.getMaxBatchSendAttempts() times (driven by RETRY replies, which increment the counter). If the attempt budget is exhausted without ever receiving RECEIVED, the loop exits and this IOException is thrown, meaning the batch was not acknowledged by the collector.

Source

Thrown at seatunnel-edge-agent/seatunnel-edge-agent-transport/src/main/java/org/apache/seatunnel/edge/agent/transport/socket/EdgeSocketLineTransport.java:84

            }
            if (EdgeSocketProtocol.RESP_DECRYPT_FAILED.equals(reply)) {
                throw new IOException(
                        "Edge socket ingress decryption failed (DECRYPT_FAILED): verify "
                                + "output.aes-secret-key-base64 matches EdgeSocket source "
                                + "secret_key");
            }
            throw new IOException(
                    "Unexpected batch response: "
                            + reply
                            + " (expected "
                            + EdgeSocketProtocol.RESP_RECEIVED
                            + ", "
                            + EdgeSocketProtocol.RESP_RETRY
                            + ", or "
                            + EdgeSocketProtocol.RESP_QUEUE_FULL_PREFIX
                            + "<ms>)");
        }
        throw new IOException(
                "Exceeded maxBatchSendAttempts="
                        + config.getMaxBatchSendAttempts()
                        + " without RECEIVED for batch "
                        + batchId);
    }

    private static void handleAuthResponse(String reply) throws IOException {
        if (EdgeSocketProtocol.RESP_REJECTED.equals(reply)) {
            throw new EdgeSocketCollectorRejectedException();
        }
        if (EdgeSocketProtocol.RESP_AUTH_FAILED.equals(reply)) {
            throw new EdgeSocketCollectorRejectedException(
                    "Edge socket authentication rejected (AUTH_FAILED): check output token matches"
                            + " EdgeSocket source secret_key");
        }
        if (!EdgeSocketProtocol.RESP_ACK.equals(reply)) {
            throw new IOException(
                    "Unexpected auth response: "

View on GitHub (pinned to cf67b549a7)

Solutions

Increase maxBatchSendAttempts (and/or initialBackoffMs/maxBackoffMs) in EdgeTransportConfig to tolerate longer collector overload
Check collector-side logs/metrics for overload or downstream sink slowness and relieve the bottleneck
Persist/requeue the failed batch (WAL) and resend with the same batchId after the collector recovers
Verify network latency between agent and collector is within expected bounds

Example fix

// before
config.setMaxBatchSendAttempts(3);
// after
config.setMaxBatchSendAttempts(20);
config.setMaxBackoffMs(30_000);

Defensive patterns

Strategy: retry

Validate before calling

// pre-check config
if (config.getMaxBatchSendAttempts() < 5) log.warn("maxBatchSendAttempts too low for unstable links");

Try / catch

try { client.send(batchId, payload); } catch (IOException e) { if (e.getMessage().contains("Exceeded maxBatchSendAttempts")) { wal.requeue(batchId, payload); } }

Prevention

Size maxBatchSendAttempts for worst-case collector load
Monitor collector queue depth and tune QUEUE_FULL backoffs
Keep the WAL so unacknowledged batches can be replayed
Alert on collector backlog before clients exhaust attempts

When it happens

Trigger: Collector keeps answering RETRY (or QUEUE_FULL) for maxBatchSendAttempts consecutive attempts — persistent collector overload, backpressure, or slow ingestion — while never confirming the batch.

Common situations: Collector under heavy load with a small maxBatchSendAttempts; maxBatchSendAttempts set to a very low value in config; network latency causing long round trips combined with tight backoff caps; collector stuck processing a downstream sink.

Understand the failure class

Background: Request timed out: what client-side request timeouts mean across libraries (Request timed out, TIMED_OUT, APITimeoutError) — this error's family across 39 libraries.

Related errors

AI-assisted analysis of apache/seatunnel@cf67b549a7 (2026-09-10). Data as JSON: /api/errors/176438960602411d. Report an issue: GitHub.