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Posted to github@beam.apache.org by GitBox <gi...@apache.org> on 2020/05/15 16:10:53 UTC
[GitHub] [beam] lukecwik commented on a change in pull request #11715: [BEAM-9977] Implement GrowableOffsetRangeTracker
lukecwik commented on a change in pull request #11715:
URL: https://github.com/apache/beam/pull/11715#discussion_r425885914
##########
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();
+ }
Review comment:
```suggestion
@FunctionalInterface
public interface RangeEndEstimator {
long estimate();
}
```
##########
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:
nit: Doesn't super.trySplit handle the to == from case already?
##########
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
Review comment:
The user should return Long.MIN_VALUE and then we will use the current position and the estimate will not take into effect.
##########
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();
+ }
Review comment:
We might want to suggest people wrap their estimator with https://guava.dev/releases/19.0/api/docs/com/google/common/base/Suppliers.html#memoizeWithExpiration(com.google.common.base.Supplier,%20long,%20java.util.concurrent.TimeUnit) if calling the estimator is expensive.
##########
File path: sdks/java/core/src/test/java/org/apache/beam/sdk/transforms/splittabledofn/GrowableOffsetRangeTrackerTest.java
##########
@@ -0,0 +1,212 @@
+/*
+ * 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.junit.Assert.assertEquals;
+import static org.junit.Assert.assertFalse;
+import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
+
+import org.apache.beam.sdk.io.range.OffsetRange;
+import org.apache.beam.sdk.transforms.splittabledofn.RestrictionTracker.Progress;
+import org.junit.Rule;
+import org.junit.Test;
+import org.junit.rules.ExpectedException;
+import org.junit.runner.RunWith;
+import org.junit.runners.JUnit4;
+
+/** Tests for {@link GrowableOffsetRangeTracker}. */
+@RunWith(JUnit4.class)
+public class GrowableOffsetRangeTrackerTest {
+ private static class SimplePoller implements GrowableOffsetRangeTracker.OffsetPoller {
+ private long estimateRangeEnd = 0;
+
+ @Override
+ public long estimateRangeEnd() {
+ return estimateRangeEnd;
+ }
+
+ public void setEstimateRangeEnd(long offset) {
+ estimateRangeEnd = offset;
+ }
+ }
+
+ @Rule public final ExpectedException expected = ExpectedException.none();
+
+ @Test
+ public void testIllegalInitialization() throws Exception {
+ expected.expect(NullPointerException.class);
+ GrowableOffsetRangeTracker tracker = new GrowableOffsetRangeTracker(0L, null);
+ }
+
+ @Test
+ public void testTryClaim() throws Exception {
+ GrowableOffsetRangeTracker tracker = new GrowableOffsetRangeTracker(0L, new SimplePoller());
+ assertTrue(tracker.tryClaim(10L));
+ assertTrue(tracker.tryClaim(100L));
+ assertFalse(tracker.tryClaim(Long.MAX_VALUE));
+ tracker.checkDone();
+ }
+
+ @Test
+ public void testCheckpointBeforeStart() throws Exception {
+ SimplePoller poller = new SimplePoller();
+ GrowableOffsetRangeTracker tracker = new GrowableOffsetRangeTracker(0L, poller);
+ poller.setEstimateRangeEnd(10);
+ SplitResult res = tracker.trySplit(0);
+ tracker.checkDone();
+ assertEquals(new OffsetRange(0, 0), res.getPrimary());
+ assertEquals(new OffsetRange(0, 0), tracker.currentRestriction());
+ assertEquals(new OffsetRange(0, Long.MAX_VALUE), res.getResidual());
+ }
+
+ @Test
+ public void testCheckpointJustStar() throws Exception {
Review comment:
```suggestion
public void testCheckpointJustStarted() throws Exception {
```
##########
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;
Review comment:
nit: poller -> estimator
##########
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
Review comment:
It might be worthwhile to add this comment to OffsetRangeTracker that the largest position is Long.MAX_VALUE - 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.
Review comment:
```suggestion
* <p>{@code estimateRangeEnd} is called to give the end offset when {@code trySplit} or {@code
* getProgress} is invoked. The end offset is exclusive for the range. It is not necessary to
* increase monotonically as its only taken into consideration when it is larger than the current
* position. When returning {@code Long.MAX_VALUE} as estimate, it means the largest possible position for
* the range is {@code Long.MAX_VALUE - 1}. Having a good estimate is important for providing a good
* signal of progress and splitting at a proper position.
```
##########
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).
Review comment:
```suggestion
* An {@link OffsetRangeTracker} for tracking a growable offset range. {@code Long.MAX_VALUE} is
* used as end range to indicate the possibility of infinity.
*
* <p>An offset range is considered growable when the end offset could grow (or change) during
* execution time (e.g., Kafka topic partition offset, appended file, ...).
```
##########
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 {
Review comment:
We should mention in this class comment that the user marks the growable offset range tracker as done by claiming Long.MAX_VALUE when they detect "end of stream"
##########
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:
Why not construct a new OffsetRangeTracker over `[cur, estimateLatestOffset)` and call trySplit on it?
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