Github user jfenc91 commented on a diff in the pull request:
https://github.com/apache/storm/pull/1679#discussion_r79662312
--- Diff:
external/storm-kafka-client/src/main/java/org/apache/storm/kafka/spout/KafkaSpout.java
---
@@ -479,16 +487,17 @@ public OffsetAndMetadata findNextCommitOffset() {
KafkaSpoutMessageId nextCommitMsg = null; // this is a
convenience variable to make it faster to create OffsetAndMetadata
for (KafkaSpoutMessageId currAckedMsg : ackedMsgs) { //
complexity is that of a linear scan on a TreeMap
- if ((currOffset = currAckedMsg.offset()) ==
initialFetchOffset || currOffset == nextCommitOffset + 1) { // found
the next offset to commit
+ if ((currOffset = currAckedMsg.offset()) ==
nextCommitOffset + 1) { // found the next offset to commit
found = true;
nextCommitMsg = currAckedMsg;
nextCommitOffset = currOffset;
} else if (currAckedMsg.offset() > nextCommitOffset + 1) {
// offset found is not continuous to the offsets listed to go in the next
commit, so stop search
LOG.debug("topic-partition [{}] has non-continuous
offset [{}]. It will be processed in a subsequent batch.", tp, currOffset);
break;
} else {
- LOG.debug("topic-partition [{}] has unexpected offset
[{}].", tp, currOffset);
- break;
+ //Received a redundant ack. Ignore and continue
processing.
--- End diff --
I saw this a couple of times before I figured it out. I have not taken the
time to reproduce this in a toy/test case, but given the error message this is
clearly a storm or storm-kafka-client issue. I got to this state in about 30
minutes of running a topology processing 800k-300k tuples a minute with about
10s latency. The input to the topology was on the order of 2k-10k tuples per
minute with a bolt that separated each input into multiple tuples. At startup
there was a high amount of failures after the separation (I was making requests
against an unwarmed ELB). I would guess that that is enough to reproduce with
random data/failures.
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