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Posted to github@beam.apache.org by GitBox <gi...@apache.org> on 2022/11/30 21:10:12 UTC
[GitHub] [beam] lukecwik commented on a diff in pull request #23491: Add MultimapState API
lukecwik commented on code in PR #23491:
URL: https://github.com/apache/beam/pull/23491#discussion_r1036396180
##########
sdks/java/core/src/main/java/org/apache/beam/sdk/state/MultimapState.java:
##########
@@ -0,0 +1,86 @@
+/*
+ * 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.state;
+
+import java.util.Map;
+import org.apache.beam.sdk.annotations.Experimental;
+import org.apache.beam.sdk.annotations.Experimental.Kind;
+
+/**
+ * A {@link ReadableState} cell mapping keys to bags of values. Keys are considered equivalent if
+ * their structural values are equivalent, see
+ * {@link org.apache.beam.sdk.coders.Coder#structuralValue} for additional details.
+ *
+ * <p>Implementations of this form of state are expected to implement multimap operations
+ * efficiently as supported by some associated backing key-value store.
+ *
+ * @param <K> the type of keys maintained by this multimap
+ * @param <V> the type of mapped values
+ */
+@Experimental(Kind.STATE)
+public interface MultimapState<K, V> extends State {
+
+ /**
+ * Associates the specified value with the specified key in this multimap. Existing values
+ * associated with the same key will not be removed.
+ *
+ * <p>Changes will not be reflected in the results returned by previous calls to {@link
+ * ReadableState#read} on the results any of the reading methods({@link #get}, {@link #keys},
+ * {@link #entries}).
+ */
+ void put(K key, V value);
+
+ /**
+ * A deferred lookup, returns an empty iterable if the item is not found.
+ *
+ * <p>A user is encouraged to call {@code get} for all relevant keys and call {@code readLater()}
+ * on the results.
+ *
+ * <p>When {@code read} is called, a particular state implementation is encouraged to perform all
+ * pending reads in a single batch.
+ */
+ ReadableState<Iterable<V>> get(K key);
+
+ /**
+ * Removes all values associated with the key from this multimap if exists.
Review Comment:
```suggestion
* Removes all values associated with the key from this multimap. This is a no-op if the key is not contained within the multimap.
```
##########
sdks/java/core/src/main/java/org/apache/beam/sdk/state/MultimapState.java:
##########
@@ -0,0 +1,86 @@
+/*
+ * 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.state;
+
+import java.util.Map;
+import org.apache.beam.sdk.annotations.Experimental;
+import org.apache.beam.sdk.annotations.Experimental.Kind;
+
+/**
+ * A {@link ReadableState} cell mapping keys to bags of values. Keys are considered equivalent if
+ * their structural values are equivalent, see
+ * {@link org.apache.beam.sdk.coders.Coder#structuralValue} for additional details.
+ *
+ * <p>Implementations of this form of state are expected to implement multimap operations
+ * efficiently as supported by some associated backing key-value store.
+ *
+ * @param <K> the type of keys maintained by this multimap
+ * @param <V> the type of mapped values
+ */
+@Experimental(Kind.STATE)
+public interface MultimapState<K, V> extends State {
+
+ /**
+ * Associates the specified value with the specified key in this multimap. Existing values
+ * associated with the same key will not be removed.
+ *
+ * <p>Changes will not be reflected in the results returned by previous calls to {@link
+ * ReadableState#read} on the results any of the reading methods({@link #get}, {@link #keys},
+ * {@link #entries}).
+ */
+ void put(K key, V value);
+
+ /**
+ * A deferred lookup, returns an empty iterable if the item is not found.
+ *
+ * <p>A user is encouraged to call {@code get} for all relevant keys and call {@code readLater()}
+ * on the results.
+ *
+ * <p>When {@code read} is called, a particular state implementation is encouraged to perform all
+ * pending reads in a single batch.
+ */
+ ReadableState<Iterable<V>> get(K key);
+
+ /**
+ * Removes all values associated with the key from this multimap if exists.
+ *
+ * <p>Changes will not be reflected in the results returned by previous calls to {@link
+ * ReadableState#read} on the results any of the reading methods({@link #get}, {@link #keys},
Review Comment:
```suggestion
* ReadableState#read} on the results of any of the reading methods({@link #get}, {@link #keys},
```
##########
runners/core-java/src/main/java/org/apache/beam/runners/core/InMemoryStateInternals.java:
##########
@@ -463,6 +476,121 @@ public InMemoryBag<T> copy() {
}
}
+ /** An {@link InMemoryState} implementation of {@link MultimapState}. */
+ public static final class InMemoryMultimap<K, V>
+ implements MultimapState<K, V>, InMemoryState<InMemoryMultimap<K, V>> {
+ private final Coder<K> keyCoder;
+ private final Coder<V> valueCoder;
+ private Multimap<Object, V> contents = ArrayListMultimap.create();
+ private Map<Object, K> structuralKeysMapping = Maps.newHashMap();
+
+ public InMemoryMultimap(Coder<K> keyCoder, Coder<V> valueCoder) {
+ this.keyCoder = keyCoder;
+ this.valueCoder = valueCoder;
+ }
+
+ @Override
+ public void clear() {
+ contents = ArrayListMultimap.create();
+ structuralKeysMapping = Maps.newHashMap();
+ }
+
+ @Override
+ public void put(K key, V value) {
+ Object structuralKey = keyCoder.structuralValue(key);
+ structuralKeysMapping.put(structuralKey, key);
+ contents.put(structuralKey, value);
+ }
+
+ @Override
+ public void remove(K key) {
+ Object structuralKey = keyCoder.structuralValue(key);
+ structuralKeysMapping.remove(structuralKey);
+ contents.removeAll(structuralKey);
+ }
+
+ @Override
+ public ReadableState<Iterable<V>> get(K key) {
+ return CollectionViewState.of(contents.get(keyCoder.structuralValue(key)));
Review Comment:
This returns a stale view in this order of operations:
```
mm.put("A", 1);
ReadableState<Iterable<V>> iter = mm.get("A");
mm.clear();
iter.read(); <-- will contain "1"
```
I believe there are other combinations where you won't get what you want. Please ensure that ParDoTest covers:
* `get` before and after remove/put/clear.
* `containsKey` before and after remove/put/clear
* `entries` before and after remove/put/clear
* `isEmpty` before and after remove/put/clear
* `keys` fore and after remove/put/clear
Currently I see your covering entries before and after put/remove.
##########
sdks/java/core/src/main/java/org/apache/beam/sdk/state/StateSpecs.java:
##########
@@ -247,6 +247,44 @@ public static <T> StateSpec<OrderedListState<T>> orderedList(Coder<T> elemCoder)
public static StateSpec<OrderedListState<Row>> rowOrderedList(Schema valueSchema) {
return new OrderedListStateSpec<>(RowCoder.of(valueSchema));
}
+
+ /**
+ * Create a {@link StateSpec} for a {@link MultimapState}, optimized for key lookups and writes.
+ *
+ * <p>This method attempts to infer the key and value coders automatically.
+ *
+ * <p>If the key and value types have schemas registered, then the schemas will be used to encode
+ * the elements.
+ *
+ * @see #multimap(Coder, Coder)
+ */
+ public static <K, V> StateSpec<MultimapState<K, V>> multimap() {
+ return new MultimapStateSpec<>(null, null);
+ }
+
+ /**
+ * Create a {@link StateSpec} for a {@link MultimapState}, optimized for key lookups and writes.
Review Comment:
```suggestion
* Create a {@link StateSpec} for a {@link MultimapState}, optimized for key lookups, key puts, and clear.
```
##########
sdks/java/core/src/main/java/org/apache/beam/sdk/state/StateSpecs.java:
##########
@@ -247,6 +247,44 @@ public static <T> StateSpec<OrderedListState<T>> orderedList(Coder<T> elemCoder)
public static StateSpec<OrderedListState<Row>> rowOrderedList(Schema valueSchema) {
return new OrderedListStateSpec<>(RowCoder.of(valueSchema));
}
+
+ /**
+ * Create a {@link StateSpec} for a {@link MultimapState}, optimized for key lookups and writes.
Review Comment:
```suggestion
* Create a {@link StateSpec} for a {@link MultimapState}, optimized for key lookups, key puts, and clear.
```
##########
runners/core-java/src/main/java/org/apache/beam/runners/core/InMemoryStateInternals.java:
##########
@@ -463,6 +476,116 @@ public InMemoryBag<T> copy() {
}
}
+ /** An {@link InMemoryState} implementation of {@link MultimapState}. */
+ public static final class InMemoryMultimap<K, V>
+ implements MultimapState<K, V>, InMemoryState<InMemoryMultimap<K, V>> {
+ private final Coder<K> keyCoder;
+ private final Coder<V> valueCoder;
+ private Multimap<K, V> contents = ArrayListMultimap.create();
+
+ public InMemoryMultimap(Coder<K> keyCoder, Coder<V> valueCoder) {
+ this.keyCoder = keyCoder;
+ this.valueCoder = valueCoder;
+ }
+
+ @Override
+ public void clear() {
+ contents = ArrayListMultimap.create();
Review Comment:
+1
##########
sdks/java/core/src/main/java/org/apache/beam/sdk/testing/UsesMultimapState.java:
##########
@@ -0,0 +1,24 @@
+/*
+ * 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.testing;
+
+import org.apache.beam.sdk.annotations.Internal;
+
+/** Category tag for validation tests which utilize {@link UsesMultimapState}. */
Review Comment:
```suggestion
import org.apache.beam.sdk.state.MultimapState;
/** Category tag for validation tests which utilize {@link MultimapState}. */
```
##########
sdks/java/core/src/main/java/org/apache/beam/sdk/state/MultimapState.java:
##########
@@ -0,0 +1,83 @@
+/*
+ * 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.state;
+
+import java.util.Map;
+import org.apache.beam.sdk.annotations.Experimental;
+import org.apache.beam.sdk.annotations.Experimental.Kind;
+
+/**
+ * A {@link ReadableState} cell mapping keys to bags of values.
+ *
+ * <p>Implementations of this form of state are expected to implement multimap operations
+ * efficiently as supported by some associated backing key-value store.
+ *
+ * @param <K> the type of keys maintained by this multimap
+ * @param <V> the type of mapped values
+ */
+@Experimental(Kind.STATE)
+public interface MultimapState<K, V> extends State {
+
+ /**
+ * Associates the specified value with the specified key in this multimap.
+ *
+ * <p>Changes will not be reflected in the results returned by previous calls to {@link
+ * ReadableState#read} on the results any of the reading methods({@link #get}, {@link #keys},
+ * {@link #entries}).
+ */
+ void put(K key, V value);
+
+ /**
+ * A deferred lookup, using null values if the item is not found.
+ *
+ * <p>A user is encouraged to call {@code get} for all relevant keys and call {@code readLater()}
+ * on the results.
+ *
+ * <p>When {@code read} is called, a particular state implementation is encouraged to perform all
+ * pending reads in a single batch.
+ */
+ ReadableState<Iterable<V>> get(K key);
+
+ /**
+ * Removes all values associated with the key from this multimap if exists.
+ *
+ * <p>Changes will not be reflected in the results returned by previous calls to {@link
+ * ReadableState#read} on the results any of the reading methods({@link #get}, {@link #keys},
+ * {@link #entries}).
+ */
+ void remove(K key);
+
+ /** Returns an {@link Iterable} over the keys contained in this multimap. */
+ ReadableState<Iterable<K>> keys();
+
+ /** Returns an {@link Iterable} over all key-values pairs contained in this multimap. */
Review Comment:
I missed that we are returning `Entry<K, Iterable<V>>` which is why I suggested the swap to `key-value` over `key-values`.
Note that other map APIs use `Entry<K, V>`, see:
https://guava.dev/releases/23.0/api/docs/com/google/common/collect/ArrayListMultimap.html#entries--
https://commons.apache.org/proper/commons-collections/apidocs/org/apache/commons/collections4/MultiValuedMap.html#entries--
It would likely make sense to match what existing common libraries do on this front so we are idiomatic for Java users.
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