ableegoldman commented on a change in pull request #9157:
URL: https://github.com/apache/kafka/pull/9157#discussion_r485222996
##########
File path:
streams/src/main/java/org/apache/kafka/streams/kstream/internals/KStreamSlidingWindowAggregate.java
##########
@@ -146,96 +165,203 @@ public void processInOrder(final K key, final V value,
final long timestamp) {
boolean leftWinAlreadyCreated = false;
boolean rightWinAlreadyCreated = false;
- // keep the left type window closest to the record
- Window latestLeftTypeWindow = null;
+ Long previousRecordTimestamp = null;
+
try (
final KeyValueIterator<Windowed<K>, ValueAndTimestamp<Agg>>
iterator = windowStore.fetch(
key,
key,
- timestamp - 2 * windows.timeDifferenceMs(),
+ Math.max(0, inputRecordTimestamp - 2 *
windows.timeDifferenceMs()),
// to catch the current record's right window, if it
exists, without more calls to the store
- timestamp + 1)
+ inputRecordTimestamp + 1)
) {
while (iterator.hasNext()) {
- final KeyValue<Windowed<K>, ValueAndTimestamp<Agg>> next =
iterator.next();
- windowStartTimes.add(next.key.window().start());
- final long startTime = next.key.window().start();
+ final KeyValue<Windowed<K>, ValueAndTimestamp<Agg>>
windowBeingProcessed = iterator.next();
+ final long startTime =
windowBeingProcessed.key.window().start();
+ windowStartTimes.add(startTime);
final long endTime = startTime +
windows.timeDifferenceMs();
+ final long windowMaxRecordTimestamp =
windowBeingProcessed.value.timestamp();
- if (endTime < timestamp) {
- leftWinAgg = next.value;
- if (isLeftWindow(next)) {
- latestLeftTypeWindow = next.key.window();
- }
- } else if (endTime == timestamp) {
+ if (endTime < inputRecordTimestamp) {
+ leftWinAgg = windowBeingProcessed.value;
+ previousRecordTimestamp = windowMaxRecordTimestamp;
+ } else if (endTime == inputRecordTimestamp) {
leftWinAlreadyCreated = true;
- putAndForward(next.key.window(), next.value, key,
value, closeTime, timestamp);
- } else if (endTime > timestamp && startTime <= timestamp) {
- rightWinAgg = next.value;
- putAndForward(next.key.window(), next.value, key,
value, closeTime, timestamp);
- } else {
+ if (windowMaxRecordTimestamp < inputRecordTimestamp) {
+ previousRecordTimestamp = windowMaxRecordTimestamp;
+ }
+
updateWindowAndForward(windowBeingProcessed.key.window(),
windowBeingProcessed.value, key, value, closeTime, inputRecordTimestamp);
+ } else if (endTime > inputRecordTimestamp && startTime <=
inputRecordTimestamp) {
+ rightWinAgg = windowBeingProcessed.value;
+
updateWindowAndForward(windowBeingProcessed.key.window(),
windowBeingProcessed.value, key, value, closeTime, inputRecordTimestamp);
+ } else if (startTime == inputRecordTimestamp + 1) {
rightWinAlreadyCreated = true;
+ } else {
+ throw new IllegalStateException("Unexpected window
found when processing sliding windows");
}
}
}
//create right window for previous record
- if (latestLeftTypeWindow != null) {
- final long rightWinStart = latestLeftTypeWindow.end() + 1;
- if (!windowStartTimes.contains(rightWinStart)) {
- final TimeWindow window = new TimeWindow(rightWinStart,
rightWinStart + windows.timeDifferenceMs());
- final ValueAndTimestamp<Agg> valueAndTime =
ValueAndTimestamp.make(initializer.apply(), timestamp);
- putAndForward(window, valueAndTime, key, value, closeTime,
timestamp);
+ if (previousRecordTimestamp != null) {
+ final long previousRightWinStart = previousRecordTimestamp + 1;
+ if (rightWindowNecessaryAndPossible(windowStartTimes,
previousRightWinStart, inputRecordTimestamp)) {
+ final TimeWindow window = new
TimeWindow(previousRightWinStart, previousRightWinStart +
windows.timeDifferenceMs());
+ final ValueAndTimestamp<Agg> valueAndTime =
ValueAndTimestamp.make(initializer.apply(), inputRecordTimestamp);
+ updateWindowAndForward(window, valueAndTime, key, value,
closeTime, inputRecordTimestamp);
}
}
//create left window for new record
if (!leftWinAlreadyCreated) {
final ValueAndTimestamp<Agg> valueAndTime;
- //there's a right window that the new record could create -->
new record's left window is not empty
- if (latestLeftTypeWindow != null) {
- valueAndTime = ValueAndTimestamp.make(leftWinAgg.value(),
timestamp);
+ // if there's a right window that the new record could create
&& previous record falls within left window -> new record's left window is not
empty
+ if (leftWindowNotEmpty(previousRecordTimestamp,
inputRecordTimestamp)) {
+ valueAndTime = ValueAndTimestamp.make(leftWinAgg.value(),
inputRecordTimestamp);
} else {
- valueAndTime = ValueAndTimestamp.make(initializer.apply(),
timestamp);
+ valueAndTime = ValueAndTimestamp.make(initializer.apply(),
inputRecordTimestamp);
}
- final TimeWindow window = new TimeWindow(timestamp -
windows.timeDifferenceMs(), timestamp);
- putAndForward(window, valueAndTime, key, value, closeTime,
timestamp);
+ final TimeWindow window = new TimeWindow(inputRecordTimestamp
- windows.timeDifferenceMs(), inputRecordTimestamp);
+ updateWindowAndForward(window, valueAndTime, key, value,
closeTime, inputRecordTimestamp);
}
- //create right window for new record
- if (!rightWinAlreadyCreated && rightWindowIsNotEmpty(rightWinAgg,
timestamp)) {
- final TimeWindow window = new TimeWindow(timestamp + 1,
timestamp + 1 + windows.timeDifferenceMs());
- final ValueAndTimestamp<Agg> valueAndTime =
ValueAndTimestamp.make(getValueOrNull(rightWinAgg),
Math.max(rightWinAgg.timestamp(), timestamp));
- putAndForward(window, valueAndTime, key, value, closeTime,
timestamp);
+ if (!rightWinAlreadyCreated && rightWindowIsNotEmpty(rightWinAgg,
inputRecordTimestamp)) {
+ createCurrentRecordRightWindow(inputRecordTimestamp,
rightWinAgg, key);
}
}
- private boolean rightWindowIsNotEmpty(final ValueAndTimestamp<Agg>
rightWinAgg, final long timestamp) {
- return rightWinAgg != null && rightWinAgg.timestamp() > timestamp;
+ /**
+ * Created to handle records where 0 < inputRecordTimestamp <
timeDifferenceMs. These records would create
+ * windows with negative start times, which is not supported. Instead,
we will put them into the [0, timeDifferenceMs]
+ * window as a "workaround", and we will update or create their right
windows as new records come in later
+ */
+ private void processEarly(final K key, final V value, final long
inputRecordTimestamp, final long closeTime) {
+ if (inputRecordTimestamp < 0 || inputRecordTimestamp >=
windows.timeDifferenceMs()) {
+ throw new IllegalArgumentException("Early record for sliding
windows must fall between 0 < inputRecordTimestamp < timeDifferenceMs");
+ }
+
+ // A window from [0, timeDifferenceMs] that holds all early records
+ KeyValue<Windowed<K>, ValueAndTimestamp<Agg>> combinedWindow =
null;
+ ValueAndTimestamp<Agg> rightWinAgg = null;
+ boolean rightWinAlreadyCreated = false;
+ final Set<Long> windowStartTimes = new HashSet<>();
+
+ Long previousRecordTimestamp = null;
+
+ try (
+ final KeyValueIterator<Windowed<K>, ValueAndTimestamp<Agg>>
iterator = windowStore.fetch(
+ key,
+ key,
+ 0,
+ // to catch the current record's right window, if it
exists, without more calls to the store
+ inputRecordTimestamp + 1)
+ ) {
+ while (iterator.hasNext()) {
+ final KeyValue<Windowed<K>, ValueAndTimestamp<Agg>>
windowBeingProcessed = iterator.next();
+ final long startTime =
windowBeingProcessed.key.window().start();
+ windowStartTimes.add(startTime);
+ final long windowMaxRecordTimestamp =
windowBeingProcessed.value.timestamp();
+
+ if (startTime == 0) {
+ combinedWindow = windowBeingProcessed;
+ //We don't need to store previousRecordTimestamp if
maxRecordTimestamp > timestamp
+ // because the previous record's right window (if
there is a previous record)
+ // would have already been created by
maxRecordTimestamp
+ if (windowMaxRecordTimestamp < inputRecordTimestamp) {
+ previousRecordTimestamp = windowMaxRecordTimestamp;
+ }
+
+ } else if (startTime <= inputRecordTimestamp) {
+ rightWinAgg = windowBeingProcessed.value;
+
updateWindowAndForward(windowBeingProcessed.key.window(),
windowBeingProcessed.value, key, value, closeTime, inputRecordTimestamp);
+ } else if (startTime == inputRecordTimestamp + 1) {
+ rightWinAlreadyCreated = true;
+ } else {
+ throw new IllegalStateException("Unexpected window
found when processing sliding windows");
+ }
+ }
+ }
+
+ // If there wasn't a right window agg found and we need a right
window for our new record,
+ // the current aggregate in the combined window will go in the new
record's right window. We can be sure that the combined
+ // window only holds records that fall into the current record's
right window for two reasons:
+ // 1. If there were records earlier than the current record AND
later than the current record, there would be a right window found
+ // when we looked for right window agg.
+ // 2. If there was only a record before the current record, we
wouldn't need a right window for the current record and wouldn't update the
+ // rightWinAgg value here, as the combinedWindow.value.timestamp()
< inputRecordTimestamp
+ if (rightWinAgg == null && combinedWindow != null &&
combinedWindow.value.timestamp() > inputRecordTimestamp) {
+ rightWinAgg = combinedWindow.value;
+ }
+
+ //create right window for new record if needed
Review comment:
nit: this code is pretty self-explanatory now, so the comment isn't
really adding anything
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