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https://issues.apache.org/jira/browse/KAFKA-13388?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17456854#comment-17456854
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David Mao commented on KAFKA-13388:
-----------------------------------
[~dhofftgt]
Looking at where the NetworkClient enters the CHECKING_API_VERSIONS state, we
see:
{code:java}
if (discoverBrokerVersions) {
this.connectionStates.checkingApiVersions(node);
nodesNeedingApiVersionsFetch.put(node, new ApiVersionsRequest.Builder());
{code}
which is a separate queue for nodes needing to send the api versions request.
Then in
{code:java}
private void handleInitiateApiVersionRequests(long now) {
Iterator<Map.Entry<String, ApiVersionsRequest.Builder>> iter =
nodesNeedingApiVersionsFetch.entrySet().iterator();
while (iter.hasNext()) {
Map.Entry<String, ApiVersionsRequest.Builder> entry = iter.next();
String node = entry.getKey();
if (selector.isChannelReady(node) &&
inFlightRequests.canSendMore(node)) {
log.debug("Initiating API versions fetch from node {}.", node);
ApiVersionsRequest.Builder apiVersionRequestBuilder =
entry.getValue();
ClientRequest clientRequest = newClientRequest(node,
apiVersionRequestBuilder, now, true);
doSend(clientRequest, true, now);
iter.remove();
}{code}
we only send out the api versions request if the channel is ready (TLS
handshake complete, SASL handshake complete).
This is actually a pretty insidious bug because I think we end up in a state
where we do not apply any request timeout to the channel, since the inflight
requests are empty.
> Kafka Producer nodes stuck in CHECKING_API_VERSIONS
> ---------------------------------------------------
>
> Key: KAFKA-13388
> URL: https://issues.apache.org/jira/browse/KAFKA-13388
> Project: Kafka
> Issue Type: Bug
> Components: core
> Reporter: David Hoffman
> Priority: Minor
> Attachments: Screen Shot 2021-10-25 at 10.28.48 AM.png,
> image-2021-10-21-13-42-06-528.png
>
>
> I have been seeing expired batch errors in my app.
> {code:java}
> org.apache.kafka.common.errors.TimeoutException: Expiring 51 record(s) for
> xxx-17:120002 ms has passed since batch creation
> {code}
> I would have assumed a request timout or connection timeout should have also
> been logged. I could not find any other associated errors.
> I added some instrumenting to my app and have traced this down to broker
> connections hanging in CHECKING_API_VERSIONS state. -It appears there is no
> effective timeout for Kafka Producer broker connections in
> CHECKING_API_VERSIONS state.-
> In the code see the after the NetworkClient connects to a broker node it
> makes a request to check api versions, when it receives the response it marks
> the node as ready. -I am seeing that sometimes a reply is not received for
> the check api versions request the connection just hangs in
> CHECKING_API_VERSIONS state until it is disposed I assume after the idle
> connection timeout.-
> Update: not actually sure what causes the connection to get stuck in
> CHECKING_API_VERSIONS.
> -I am guessing the connection setup timeout should be still in play for this,
> but it is not.-
> -There is a connectingNodes set that is consulted when checking timeouts and
> the node is removed-
> -when ClusterConnectionStates.checkingApiVersions(String id) is called to
> transition the node into CHECKING_API_VERSIONS-
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