Github user hmcl commented on a diff in the pull request:
https://github.com/apache/storm/pull/1679#discussion_r86892802
--- 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 --
@jfenc91 @srdo This behavior still seems quite surprising to me. However,
this fix probably won't have any bad side effect, so it should be OK. Perhaps
you can add to the log message that we are ignoring it as it is out of order,
duplicate, or something like that.
@revans2 can you please comment on why, or if it is possible a tuple to be
acked more than once?
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