spena commented on a change in pull request #10462:
URL: https://github.com/apache/kafka/pull/10462#discussion_r611915606
##########
File path:
streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamKStreamJoin.java
##########
@@ -102,14 +127,98 @@ public void process(final K key, final V1 value) {
while (iter.hasNext()) {
needOuterJoin = false;
final KeyValue<Long, V2> otherRecord = iter.next();
+ final long otherRecordTimestamp = otherRecord.key;
context().forward(
key,
joiner.apply(key, value, otherRecord.value),
- To.all().withTimestamp(Math.max(inputRecordTimestamp,
otherRecord.key)));
+ To.all().withTimestamp(Math.max(inputRecordTimestamp,
otherRecordTimestamp)));
+
+ outerJoinWindowStore.ifPresent(store -> {
+ // Delete the other joined key from the outer
non-joined store now to prevent
+ // further processing
+ final KeyAndJoinSide<K> otherJoinKey =
KeyAndJoinSide.make(!thisJoin, key);
+ if (store.fetch(otherJoinKey, otherRecordTimestamp) !=
null) {
+ store.put(otherJoinKey, null,
otherRecordTimestamp);
+ }
+ });
}
if (needOuterJoin) {
- context().forward(key, joiner.apply(key, value, null));
+ // The maxStreamTime contains the max time observed in
both sides of the join.
+ // Having access to the time observed in the other join
side fixes the following
+ // problem:
+ //
+ // Say we have a window size of 5 seconds
+ // 1. A non-joined record wth time T10 is seen in the
left-topic (maxLeftStreamTime: 10)
+ // The record is not processed yet, and is added to
the outer-join store
+ // 2. A non-joined record with time T2 is seen in the
right-topic (maxRightStreamTime: 2)
+ // The record is not processed yet, and is added to
the outer-join store
+ // 3. A joined record with time T11 is seen in the
left-topic (maxLeftStreamTime: 11)
+ // It is time to look at the expired records. T10 and
T2 should be emitted, but
+ // because T2 was late, then it is not fetched by the
window store, so it is not processed
+ //
+ // See KStreamKStreamLeftJoinTest.testLowerWindowBound()
tests
+ //
+ // the condition below allows us to process the late
record without the need
+ // to hold it in the temporary outer store
+ if (timeTo < maxStreamTime) {
+ context().forward(key, joiner.apply(key, value, null));
+ } else {
+ outerJoinWindowStore.ifPresent(store -> store.put(
+ KeyAndJoinSide.make(thisJoin, key),
+ makeValueOrOtherValue(thisJoin, value),
+ inputRecordTimestamp));
+ }
+ }
+
+ outerJoinWindowStore.ifPresent(store -> {
+ // only emit left/outer non-joined if the stream time has
advanced (inputRecordTime = maxStreamTime)
+ // if the current record is late, then there is no need to
check for expired records
+ if (inputRecordTimestamp == maxStreamTime) {
+ maybeEmitOuterExpiryRecords(store, maxStreamTime);
+ }
+ });
+ }
+ }
+
+ private ValueOrOtherValue makeValueOrOtherValue(final boolean
thisJoin, final V1 value) {
Review comment:
Done
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