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https://issues.apache.org/jira/browse/BEAM-9977?focusedWorklogId=433840&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-433840
]
ASF GitHub Bot logged work on BEAM-9977:
----------------------------------------
Author: ASF GitHub Bot
Created on: 15/May/20 18:49
Start Date: 15/May/20 18:49
Worklog Time Spent: 10m
Work Description: boyuanzz commented on a change in pull request #11715:
URL: https://github.com/apache/beam/pull/11715#discussion_r425986350
##########
File path:
sdks/java/core/src/main/java/org/apache/beam/sdk/transforms/splittabledofn/GrowableOffsetRangeTracker.java
##########
@@ -0,0 +1,103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.transforms.splittabledofn;
+
+import static
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkNotNull;
+
+import org.apache.beam.sdk.annotations.Experimental;
+import org.apache.beam.sdk.annotations.Experimental.Kind;
+import org.apache.beam.sdk.io.range.OffsetRange;
+
+/**
+ * A special {@link OffsetRangeTracker} for tracking a growable offset range.
The Long.MAX_VALUE is
+ * used as end range to indicate the possibility of infinity.
+ *
+ * <p>A offset range is considered as growable when the end offset could
grow(or change) during
+ * execution time(e.g., Kafka backlog, appended file).
+ */
+@Experimental(Kind.SPLITTABLE_DO_FN)
+public class GrowableOffsetRangeTracker extends OffsetRangeTracker {
+ /**
+ * An interface that should be implemented to fetch estimated end offset of
range.
+ *
+ * <p>{@code estimateRangeEnd} is called to give te end offset when {@code
trySplit} or {@code
+ * getProgress} is invoked. The end offset is exclusive for the range. It's
not necessary to
+ * increase monotonically but it's only taken into computation when it's
larger than the current
+ * position. When returning Long.MAX_VALUE as estimate, it means the largest
possible position for
+ * the range is Long.MAX_VALUE - 1. Having a good estimate is important for
providing a good
+ * signal of progress and splitting at a proper position.
+ */
+ public interface OffsetPoller {
+ long estimateRangeEnd();
+ }
+
+ private final OffsetPoller poller;
+
+ public GrowableOffsetRangeTracker(long start, OffsetPoller offsetPoller) {
+ super(new OffsetRange(start, Long.MAX_VALUE));
+ this.poller = checkNotNull(offsetPoller);
+ }
+
+ @Override
+ public SplitResult<OffsetRange> trySplit(double fractionOfRemainder) {
+ // If current tracking range is no longer growable, split it as a normal
range.
+ if (range.getTo() != Long.MAX_VALUE || range.getTo() == range.getFrom()) {
+ return super.trySplit(fractionOfRemainder);
+ }
+ long cur = (lastAttemptedOffset == null) ? range.getFrom() - 1 :
lastAttemptedOffset;
+
+ // If current range has been done, there is no more space to split.
+ if (cur == Long.MAX_VALUE) {
+ return null;
+ }
+ // Fetch the estimated end offset. If the estimated end is smaller than
the next offset, use
+ // the next offset as end.
+ long estimateLatestOffset = Long.max(poller.estimateRangeEnd(), cur + 1);
+ long splitPos =
+ cur
+ + Math.max(
+ 1L,
+ (Double.valueOf((estimateLatestOffset - cur) *
fractionOfRemainder)).longValue());
+
+ if (splitPos > estimateLatestOffset) {
+ return null;
+ }
+ OffsetRange res = new OffsetRange(splitPos, range.getTo());
+ this.range = new OffsetRange(range.getFrom(), splitPos);
+ return SplitResult.of(range, res);
Review comment:
There is a slight difference around comparison of `splitPos` and `end`.
`GrowableOffsetTracker` allows split when `splitPos <= end` but
`OffsetRangeTracker` allows split when `splitPos < end`. The purpose of
`OffsetRangeTracker` is to reduce resuming from an empty range. The purpose of
`GrowableOffsetRangeTracker` is to handle split at `cur + 1`.
##########
File path:
sdks/java/core/src/main/java/org/apache/beam/sdk/transforms/splittabledofn/GrowableOffsetRangeTracker.java
##########
@@ -0,0 +1,103 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements. See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership. The ASF licenses this file
+ * to you under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance
+ * with the License. You may obtain a copy of the License at
+ *
+ * http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package org.apache.beam.sdk.transforms.splittabledofn;
+
+import static
org.apache.beam.vendor.guava.v26_0_jre.com.google.common.base.Preconditions.checkNotNull;
+
+import org.apache.beam.sdk.annotations.Experimental;
+import org.apache.beam.sdk.annotations.Experimental.Kind;
+import org.apache.beam.sdk.io.range.OffsetRange;
+
+/**
+ * A special {@link OffsetRangeTracker} for tracking a growable offset range.
The Long.MAX_VALUE is
+ * used as end range to indicate the possibility of infinity.
+ *
+ * <p>A offset range is considered as growable when the end offset could
grow(or change) during
+ * execution time(e.g., Kafka backlog, appended file).
+ */
+@Experimental(Kind.SPLITTABLE_DO_FN)
+public class GrowableOffsetRangeTracker extends OffsetRangeTracker {
+ /**
+ * An interface that should be implemented to fetch estimated end offset of
range.
+ *
+ * <p>{@code estimateRangeEnd} is called to give te end offset when {@code
trySplit} or {@code
+ * getProgress} is invoked. The end offset is exclusive for the range. It's
not necessary to
+ * increase monotonically but it's only taken into computation when it's
larger than the current
+ * position. When returning Long.MAX_VALUE as estimate, it means the largest
possible position for
+ * the range is Long.MAX_VALUE - 1. Having a good estimate is important for
providing a good
+ * signal of progress and splitting at a proper position.
+ */
+ public interface OffsetPoller {
+ long estimateRangeEnd();
+ }
+
+ private final OffsetPoller poller;
+
+ public GrowableOffsetRangeTracker(long start, OffsetPoller offsetPoller) {
+ super(new OffsetRange(start, Long.MAX_VALUE));
+ this.poller = checkNotNull(offsetPoller);
+ }
+
+ @Override
+ public SplitResult<OffsetRange> trySplit(double fractionOfRemainder) {
+ // If current tracking range is no longer growable, split it as a normal
range.
+ if (range.getTo() != Long.MAX_VALUE || range.getTo() == range.getFrom()) {
Review comment:
Yes `super.trySplit()` handles empty range. The special case here is to
handle `range.getTo() == range.getFrom == Long.MAX_VALUE`.
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Issue Time Tracking
-------------------
Worklog Id: (was: 433840)
Time Spent: 50m (was: 40m)
> Build Kafka Read on top of Java SplittableDoFn
> ----------------------------------------------
>
> Key: BEAM-9977
> URL: https://issues.apache.org/jira/browse/BEAM-9977
> Project: Beam
> Issue Type: New Feature
> Components: io-java-kafka
> Reporter: Boyuan Zhang
> Assignee: Boyuan Zhang
> Priority: Major
> Time Spent: 50m
> Remaining Estimate: 0h
>
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