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https://issues.apache.org/jira/browse/KAFKA-20854?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Ken Huang updated KAFKA-20854:
------------------------------
Description:
AsyncKafkaConsumer wakes up the background thread to process the poll request:
{code:java}
if (inflightPoll == null) {
inflightPoll = new AsyncPollEvent(calculateDeadlineMs(timer),
time.milliseconds());
newlySubmittedEvent = true;
log.trace("Inflight event {} submitted", inflightPoll);
applicationEventHandler.add(inflightPoll);
}
{code}
And `FetchRequestManager` wakes up the main thread if there are no requests to
send:
{code:java}
if (fetchRequests.isEmpty()) {
// If there's nothing to fetch, wake up the FetchBuffer so it
doesn't needlessly wait for a wakeup
// that won't come until the data in the fetch buffer is
consumed.
fetchBuffer.wakeup();
pendingFetchRequestFuture.complete(null);
return PollResult.EMPTY;
}
{code}
This is an existing issue, and it has become more obvious after KIP-909, since
we moved DNS resolution into the poll phase. This means no requests can be sent
until DNS resolution completes..
was:
AsyncKafkaConsumer wakes up the background thread to process the poll request:
{code:java}
if (inflightPoll == null) {
inflightPoll = new AsyncPollEvent(calculateDeadlineMs(timer),
time.milliseconds());
newlySubmittedEvent = true;
log.trace("Inflight event {} submitted", inflightPoll);
applicationEventHandler.add(inflightPoll);
}
{code}
And `FetchRequestManager` wakes up the main thread if there are no requests to
send:
{code:java}
if (fetchRequests.isEmpty()) {
// If there's nothing to fetch, wake up the FetchBuffer so it
doesn't needlessly wait for a wakeup
// that won't come until the data in the fetch buffer is
consumed.
fetchBuffer.wakeup();
pendingFetchRequestFuture.complete(null);
return PollResult.EMPTY;
}
{code}
This is an existing issue, and it has become more obvious after KIP-919, since
we moved DNS resolution into the poll phase. This means no requests can be sent
until DNS resolution completes..
> A more obvious busy loop due to KIP-909
> ---------------------------------------
>
> Key: KAFKA-20854
> URL: https://issues.apache.org/jira/browse/KAFKA-20854
> Project: Kafka
> Issue Type: Bug
> Reporter: Chia-Ping Tsai
> Assignee: Ken Huang
> Priority: Critical
>
> AsyncKafkaConsumer wakes up the background thread to process the poll request:
> {code:java}
> if (inflightPoll == null) {
> inflightPoll = new AsyncPollEvent(calculateDeadlineMs(timer),
> time.milliseconds());
> newlySubmittedEvent = true;
> log.trace("Inflight event {} submitted", inflightPoll);
> applicationEventHandler.add(inflightPoll);
> }
> {code}
> And `FetchRequestManager` wakes up the main thread if there are no requests
> to send:
> {code:java}
> if (fetchRequests.isEmpty()) {
> // If there's nothing to fetch, wake up the FetchBuffer so it
> doesn't needlessly wait for a wakeup
> // that won't come until the data in the fetch buffer is
> consumed.
> fetchBuffer.wakeup();
> pendingFetchRequestFuture.complete(null);
> return PollResult.EMPTY;
> }
> {code}
> This is an existing issue, and it has become more obvious after KIP-909,
> since we moved DNS resolution into the poll phase. This means no requests can
> be sent until DNS resolution completes..
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