lihaosky commented on a change in pull request #11917: URL: https://github.com/apache/kafka/pull/11917#discussion_r836944209
########## File path: streams/src/main/java/org/apache/kafka/streams/state/internals/AbstractRocksDBTimeOrderedSegmentedBytesStore.java ########## @@ -0,0 +1,266 @@ +/* + * 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.kafka.streams.state.internals; Review comment: Right ########## File path: streams/src/main/java/org/apache/kafka/streams/state/internals/PrefixedSessionKeySchemas.java ########## @@ -0,0 +1,376 @@ +/* + * 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.kafka.streams.state.internals; + +import org.apache.kafka.common.serialization.Deserializer; +import org.apache.kafka.common.serialization.Serializer; +import org.apache.kafka.common.utils.Bytes; +import org.apache.kafka.streams.kstream.Window; +import org.apache.kafka.streams.kstream.Windowed; + +import java.nio.ByteBuffer; +import java.util.List; +import org.apache.kafka.streams.kstream.internals.SessionWindow; +import org.apache.kafka.streams.state.internals.SegmentedBytesStore.KeySchema; + +import static org.apache.kafka.streams.state.StateSerdes.TIMESTAMP_SIZE; + +public class PrefixedSessionKeySchemas { + + private static final int PREFIX_SIZE = 1; + private static final byte TIME_FIRST_PREFIX = 0; + private static final byte KEY_FIRST_PREFIX = 1; + + private static byte extractPrefix(final byte[] binaryBytes) { + return binaryBytes[0]; + } + + public static class TimeFirstSessionKeySchema implements KeySchema { + + @Override + public Bytes upperRange(final Bytes key, final long to) { + if (key == null) { + // Put next prefix instead of null so that we can start from right prefix + // when scanning backwards + final byte nextPrefix = TIME_FIRST_PREFIX + 1; + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE).put(nextPrefix).array()); + } + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + 2 * TIMESTAMP_SIZE + key.get().length) + .put(TIME_FIRST_PREFIX) + // the end timestamp can be as large as possible as long as it's larger than start time + .putLong(Long.MAX_VALUE) + // this is the start timestamp + .putLong(to) + .put(key.get()) + .array()); + } + + @Override + public Bytes lowerRange(final Bytes key, final long from) { + if (key == null) { + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + TIMESTAMP_SIZE) + .put(TIME_FIRST_PREFIX) + .putLong(from) + .array()); + } + + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + 2 * TIMESTAMP_SIZE + key.get().length) + .put(TIME_FIRST_PREFIX) + .putLong(from) + .putLong(0L) + .put(key.get()) + .array()); + } + + /** + * + * @param key the key in the range + * @param to the latest start time + * @return + */ + @Override + public Bytes upperRangeFixedSize(final Bytes key, final long to) { + return toBinary(key, to, Long.MAX_VALUE); + } + + /** + * + * @param key the key in the range + * @param from the earliest end timestamp in the range + * @return + */ + @Override + public Bytes lowerRangeFixedSize(final Bytes key, final long from) { + return toBinary(key, 0, Math.max(0, from)); + } + + @Override + public long segmentTimestamp(final Bytes key) { + return extractEndTimestamp(key.get()); + } + + @Override + public HasNextCondition hasNextCondition(final Bytes binaryKeyFrom, + final Bytes binaryKeyTo, final long from, final long to, final boolean forward) { + return iterator -> { + while (iterator.hasNext()) { + final Bytes bytes = iterator.peekNextKey(); + final byte prefix = extractPrefix(bytes.get()); + + if (prefix != TIME_FIRST_PREFIX) { + return false; + } + + final Windowed<Bytes> windowedKey = from(bytes); + final long endTime = windowedKey.window().end(); + final long startTime = windowedKey.window().start(); + + // We can return false directly here since keys are sorted by end time and if + // we get time smaller than `from`, there won't be time within range. + if (!forward && endTime < from) { + return false; + } + + if ((binaryKeyFrom == null || windowedKey.key().compareTo(binaryKeyFrom) >= 0) + && (binaryKeyTo == null || windowedKey.key().compareTo(binaryKeyTo) <= 0) + && endTime >= from && startTime <= to) { + return true; + } + iterator.next(); + } + return false; + }; + } + + @Override + public <S extends Segment> List<S> segmentsToSearch(final Segments<S> segments, + final long from, + final long to, + final boolean forward) { + return segments.segments(from, Long.MAX_VALUE, forward); + } + + static long extractStartTimestamp(final byte[] binaryKey) { + return ByteBuffer.wrap(binaryKey).getLong(PREFIX_SIZE + TIMESTAMP_SIZE); + } + + static long extractEndTimestamp(final byte[] binaryKey) { + return ByteBuffer.wrap(binaryKey).getLong(PREFIX_SIZE); Review comment: `binaryKey.length - TIMESTAMP_SIZE` and `binaryKey.length - 2 * TIMESTAMP_SIZE` are used in `KeyFirstSessionKeySchema` functions since time are put after key? ########## File path: streams/src/main/java/org/apache/kafka/streams/state/internals/RocksDBTimeOrderedSessionSegmentedBytesStore.java ########## @@ -0,0 +1,136 @@ +/* + * 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.kafka.streams.state.internals; + +import java.util.Collection; +import java.util.HashMap; +import java.util.Map; +import java.util.Optional; +import org.apache.kafka.clients.consumer.ConsumerRecord; +import org.apache.kafka.common.utils.Bytes; +import org.apache.kafka.streams.KeyValue; +import org.apache.kafka.streams.errors.ProcessorStateException; +import org.apache.kafka.streams.kstream.Window; +import org.apache.kafka.streams.kstream.Windowed; +import org.apache.kafka.streams.processor.internals.ChangelogRecordDeserializationHelper; +import org.apache.kafka.streams.state.KeyValueIterator; +import org.apache.kafka.streams.state.internals.PrefixedSessionKeySchemas.KeyFirstSessionKeySchema; +import org.apache.kafka.streams.state.internals.PrefixedSessionKeySchemas.TimeFirstSessionKeySchema; +import org.rocksdb.RocksDBException; +import org.rocksdb.WriteBatch; + +/** + * A RocksDB backed time-ordered segmented bytes store for session key schema. + */ +public class RocksDBTimeOrderedSessionSegmentedBytesStore extends AbstractRocksDBTimeOrderedSegmentedBytesStore { + + private class SessionKeySchemaIndexToBaseStoreIterator extends IndexToBaseStoreIterator { + SessionKeySchemaIndexToBaseStoreIterator(final KeyValueIterator<Bytes, byte[]> indexIterator) { + super(indexIterator); + } + + @Override + protected Bytes getBaseKey(final Bytes indexKey) { + final Window window = KeyFirstSessionKeySchema.extractWindow(indexKey.get()); + final byte[] key = KeyFirstSessionKeySchema.extractKeyBytes(indexKey.get()); + + return TimeFirstSessionKeySchema.toBinary(Bytes.wrap(key), window.start(), window.end()); + } + } + + RocksDBTimeOrderedSessionSegmentedBytesStore(final String name, + final String metricsScope, + final long retention, + final long segmentInterval, + final boolean withIndex) { + super(name, metricsScope, retention, segmentInterval, new TimeFirstSessionKeySchema(), + Optional.ofNullable(withIndex ? new KeyFirstSessionKeySchema() : null)); + } + + public byte[] fetchSession(final Bytes key, + final long earliestSessionEndTime, + final long latestSessionStartTime) { + return get(TimeFirstSessionKeySchema.toBinary( + key, + earliestSessionEndTime, + latestSessionStartTime + )); + } + + public void remove(final Windowed<Bytes> key) { + remove(TimeFirstSessionKeySchema.toBinary(key)); + } + + public void put(final Windowed<Bytes> sessionKey, final byte[] aggregate) { + put(TimeFirstSessionKeySchema.toBinary(sessionKey), aggregate); + } + + @Override + protected KeyValue<Bytes, byte[]> getIndexKeyValue(final Bytes baseKey, final byte[] baseValue) { + final Window window = TimeFirstSessionKeySchema.extractWindow(baseKey.get()); + final byte[] key = TimeFirstSessionKeySchema.extractKeyBytes(baseKey.get()); + return KeyValue.pair(KeyFirstSessionKeySchema.toBinary(Bytes.wrap(key), window.start(), window.end()), new byte[0]); + } + + @Override + Map<KeyValueSegment, WriteBatch> getWriteBatches( + final Collection<ConsumerRecord<byte[], byte[]>> records) { + // advance stream time to the max timestamp in the batch + for (final ConsumerRecord<byte[], byte[]> record : records) { + final long timestamp = SessionKeySchema.extractEndTimestamp(record.key()); + observedStreamTime = Math.max(observedStreamTime, timestamp); + } + + final Map<KeyValueSegment, WriteBatch> writeBatchMap = new HashMap<>(); + for (final ConsumerRecord<byte[], byte[]> record : records) { + final long timestamp = SessionKeySchema.extractEndTimestamp(record.key()); + final long segmentId = segments.segmentId(timestamp); + final KeyValueSegment segment = segments.getOrCreateSegmentIfLive(segmentId, context, observedStreamTime); + if (segment != null) { + ChangelogRecordDeserializationHelper.applyChecksAndUpdatePosition( + record, + consistencyEnabled, + position + ); + try { + final WriteBatch batch = writeBatchMap.computeIfAbsent(segment, s -> new WriteBatch()); + + // Assuming changelog record is serialized using SessionKeySchema + // from ChangeLoggingSessionBytesStore. Reconstruct key/value to restore + if (hasIndex()) { + final byte[] indexKey = KeyFirstSessionKeySchema.fromNonPrefixSessionKey(record.key()); + // Take care of tombstone + final byte[] value = record.value() == null ? null : new byte[0]; + segment.addToBatch(new KeyValue<>(indexKey, value), batch); + } + + final byte[] baseKey = TimeFirstSessionKeySchema.fromNonPrefixSessionKey(record.key()); Review comment: Do you mean less efficient than `RocksDBTimeOrderedSegmentedBytesStore`? It's similar to that one. But that one is also not efficient... ########## File path: streams/src/main/java/org/apache/kafka/streams/state/internals/PrefixedSessionKeySchemas.java ########## @@ -0,0 +1,376 @@ +/* + * 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.kafka.streams.state.internals; + +import org.apache.kafka.common.serialization.Deserializer; +import org.apache.kafka.common.serialization.Serializer; +import org.apache.kafka.common.utils.Bytes; +import org.apache.kafka.streams.kstream.Window; +import org.apache.kafka.streams.kstream.Windowed; + +import java.nio.ByteBuffer; +import java.util.List; +import org.apache.kafka.streams.kstream.internals.SessionWindow; +import org.apache.kafka.streams.state.internals.SegmentedBytesStore.KeySchema; + +import static org.apache.kafka.streams.state.StateSerdes.TIMESTAMP_SIZE; + +public class PrefixedSessionKeySchemas { + + private static final int PREFIX_SIZE = 1; + private static final byte TIME_FIRST_PREFIX = 0; + private static final byte KEY_FIRST_PREFIX = 1; + + private static byte extractPrefix(final byte[] binaryBytes) { + return binaryBytes[0]; + } + + public static class TimeFirstSessionKeySchema implements KeySchema { + + @Override + public Bytes upperRange(final Bytes key, final long to) { + if (key == null) { + // Put next prefix instead of null so that we can start from right prefix + // when scanning backwards + final byte nextPrefix = TIME_FIRST_PREFIX + 1; + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE).put(nextPrefix).array()); + } + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + 2 * TIMESTAMP_SIZE + key.get().length) + .put(TIME_FIRST_PREFIX) + // the end timestamp can be as large as possible as long as it's larger than start time + .putLong(Long.MAX_VALUE) + // this is the start timestamp + .putLong(to) + .put(key.get()) + .array()); + } + + @Override + public Bytes lowerRange(final Bytes key, final long from) { + if (key == null) { + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + TIMESTAMP_SIZE) + .put(TIME_FIRST_PREFIX) + .putLong(from) + .array()); + } + + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + 2 * TIMESTAMP_SIZE + key.get().length) + .put(TIME_FIRST_PREFIX) + .putLong(from) + .putLong(0L) + .put(key.get()) + .array()); + } + + /** + * + * @param key the key in the range + * @param to the latest start time + * @return + */ + @Override + public Bytes upperRangeFixedSize(final Bytes key, final long to) { + return toBinary(key, to, Long.MAX_VALUE); + } + + /** + * + * @param key the key in the range + * @param from the earliest end timestamp in the range + * @return + */ + @Override + public Bytes lowerRangeFixedSize(final Bytes key, final long from) { + return toBinary(key, 0, Math.max(0, from)); + } + + @Override + public long segmentTimestamp(final Bytes key) { + return extractEndTimestamp(key.get()); + } + + @Override + public HasNextCondition hasNextCondition(final Bytes binaryKeyFrom, + final Bytes binaryKeyTo, final long from, final long to, final boolean forward) { + return iterator -> { + while (iterator.hasNext()) { + final Bytes bytes = iterator.peekNextKey(); + final byte prefix = extractPrefix(bytes.get()); + + if (prefix != TIME_FIRST_PREFIX) { + return false; + } + + final Windowed<Bytes> windowedKey = from(bytes); + final long endTime = windowedKey.window().end(); + final long startTime = windowedKey.window().start(); + + // We can return false directly here since keys are sorted by end time and if + // we get time smaller than `from`, there won't be time within range. + if (!forward && endTime < from) { + return false; + } + + if ((binaryKeyFrom == null || windowedKey.key().compareTo(binaryKeyFrom) >= 0) + && (binaryKeyTo == null || windowedKey.key().compareTo(binaryKeyTo) <= 0) + && endTime >= from && startTime <= to) { + return true; + } + iterator.next(); + } + return false; + }; + } + + @Override + public <S extends Segment> List<S> segmentsToSearch(final Segments<S> segments, + final long from, + final long to, + final boolean forward) { + return segments.segments(from, Long.MAX_VALUE, forward); + } + + static long extractStartTimestamp(final byte[] binaryKey) { + return ByteBuffer.wrap(binaryKey).getLong(PREFIX_SIZE + TIMESTAMP_SIZE); + } + + static long extractEndTimestamp(final byte[] binaryKey) { + return ByteBuffer.wrap(binaryKey).getLong(PREFIX_SIZE); + } + + private static <K> K extractKey(final byte[] binaryKey, + final Deserializer<K> deserializer, + final String topic) { + return deserializer.deserialize(topic, extractKeyBytes(binaryKey)); + } + + static byte[] extractKeyBytes(final byte[] binaryKey) { + final byte[] bytes = new byte[binaryKey.length - 2 * TIMESTAMP_SIZE - PREFIX_SIZE]; + System.arraycopy(binaryKey, PREFIX_SIZE + 2 * TIMESTAMP_SIZE, bytes, 0, bytes.length); + return bytes; + } + + static Window extractWindow(final byte[] binaryKey) { + final ByteBuffer buffer = ByteBuffer.wrap(binaryKey); + final long start = buffer.getLong(PREFIX_SIZE + TIMESTAMP_SIZE); + final long end = buffer.getLong(PREFIX_SIZE); + return new SessionWindow(start, end); + } + + public static Windowed<Bytes> from(final Bytes bytesKey) { + final byte[] binaryKey = bytesKey.get(); + final Window window = extractWindow(binaryKey); + return new Windowed<>(Bytes.wrap(extractKeyBytes(binaryKey)), window); + } + + public static <K> Windowed<K> from(final byte[] binaryKey, + final Deserializer<K> keyDeserializer, + final String topic) { + final K key = extractKey(binaryKey, keyDeserializer, topic); + final Window window = extractWindow(binaryKey); + return new Windowed<>(key, window); + } + + public static <K> byte[] toBinary(final Windowed<K> sessionKey, + final Serializer<K> serializer, + final String topic) { + final byte[] bytes = serializer.serialize(topic, sessionKey.key()); + return toBinary(Bytes.wrap(bytes), sessionKey.window().start(), sessionKey.window().end()).get(); + } + + public static Bytes toBinary(final Windowed<Bytes> sessionKey) { Review comment: Do you mean consolidate the `toBinary` in `KeyFirstSessionKeySchema` with `toBinary` in `SessionKeySchema`? `toBinary` here is different not only because of first byte. ########## File path: streams/src/main/java/org/apache/kafka/streams/state/internals/PrefixedSessionKeySchemas.java ########## @@ -0,0 +1,376 @@ +/* + * 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.kafka.streams.state.internals; + +import org.apache.kafka.common.serialization.Deserializer; +import org.apache.kafka.common.serialization.Serializer; +import org.apache.kafka.common.utils.Bytes; +import org.apache.kafka.streams.kstream.Window; +import org.apache.kafka.streams.kstream.Windowed; + +import java.nio.ByteBuffer; +import java.util.List; +import org.apache.kafka.streams.kstream.internals.SessionWindow; +import org.apache.kafka.streams.state.internals.SegmentedBytesStore.KeySchema; + +import static org.apache.kafka.streams.state.StateSerdes.TIMESTAMP_SIZE; + +public class PrefixedSessionKeySchemas { + + private static final int PREFIX_SIZE = 1; + private static final byte TIME_FIRST_PREFIX = 0; + private static final byte KEY_FIRST_PREFIX = 1; + + private static byte extractPrefix(final byte[] binaryBytes) { + return binaryBytes[0]; + } + + public static class TimeFirstSessionKeySchema implements KeySchema { + + @Override + public Bytes upperRange(final Bytes key, final long to) { + if (key == null) { + // Put next prefix instead of null so that we can start from right prefix + // when scanning backwards + final byte nextPrefix = TIME_FIRST_PREFIX + 1; + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE).put(nextPrefix).array()); + } + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + 2 * TIMESTAMP_SIZE + key.get().length) + .put(TIME_FIRST_PREFIX) + // the end timestamp can be as large as possible as long as it's larger than start time + .putLong(Long.MAX_VALUE) + // this is the start timestamp + .putLong(to) + .put(key.get()) + .array()); + } + + @Override + public Bytes lowerRange(final Bytes key, final long from) { + if (key == null) { + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + TIMESTAMP_SIZE) + .put(TIME_FIRST_PREFIX) + .putLong(from) + .array()); + } + + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + 2 * TIMESTAMP_SIZE + key.get().length) + .put(TIME_FIRST_PREFIX) + .putLong(from) + .putLong(0L) + .put(key.get()) + .array()); + } + + /** + * + * @param key the key in the range + * @param to the latest start time + * @return + */ + @Override + public Bytes upperRangeFixedSize(final Bytes key, final long to) { + return toBinary(key, to, Long.MAX_VALUE); + } + + /** + * + * @param key the key in the range + * @param from the earliest end timestamp in the range + * @return + */ + @Override + public Bytes lowerRangeFixedSize(final Bytes key, final long from) { + return toBinary(key, 0, Math.max(0, from)); + } + + @Override + public long segmentTimestamp(final Bytes key) { + return extractEndTimestamp(key.get()); + } + + @Override + public HasNextCondition hasNextCondition(final Bytes binaryKeyFrom, + final Bytes binaryKeyTo, final long from, final long to, final boolean forward) { + return iterator -> { + while (iterator.hasNext()) { + final Bytes bytes = iterator.peekNextKey(); + final byte prefix = extractPrefix(bytes.get()); + + if (prefix != TIME_FIRST_PREFIX) { Review comment: Because keys with `KEY_FIRST_PREFIX` are stored in the same DB, if range query's upperrange is null, the end prefix is ``` final byte nextPrefix = TIME_FIRST_PREFIX + 1; return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE).put(nextPrefix).array()); ``` See line 46 - 50 ########## File path: streams/src/main/java/org/apache/kafka/streams/state/internals/PrefixedSessionKeySchemas.java ########## @@ -0,0 +1,376 @@ +/* + * 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.kafka.streams.state.internals; + +import org.apache.kafka.common.serialization.Deserializer; +import org.apache.kafka.common.serialization.Serializer; +import org.apache.kafka.common.utils.Bytes; +import org.apache.kafka.streams.kstream.Window; +import org.apache.kafka.streams.kstream.Windowed; + +import java.nio.ByteBuffer; +import java.util.List; +import org.apache.kafka.streams.kstream.internals.SessionWindow; +import org.apache.kafka.streams.state.internals.SegmentedBytesStore.KeySchema; + +import static org.apache.kafka.streams.state.StateSerdes.TIMESTAMP_SIZE; + +public class PrefixedSessionKeySchemas { + + private static final int PREFIX_SIZE = 1; + private static final byte TIME_FIRST_PREFIX = 0; + private static final byte KEY_FIRST_PREFIX = 1; + + private static byte extractPrefix(final byte[] binaryBytes) { + return binaryBytes[0]; + } + + public static class TimeFirstSessionKeySchema implements KeySchema { + + @Override + public Bytes upperRange(final Bytes key, final long to) { + if (key == null) { + // Put next prefix instead of null so that we can start from right prefix + // when scanning backwards + final byte nextPrefix = TIME_FIRST_PREFIX + 1; + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE).put(nextPrefix).array()); + } + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + 2 * TIMESTAMP_SIZE + key.get().length) + .put(TIME_FIRST_PREFIX) + // the end timestamp can be as large as possible as long as it's larger than start time + .putLong(Long.MAX_VALUE) + // this is the start timestamp + .putLong(to) + .put(key.get()) + .array()); + } + + @Override + public Bytes lowerRange(final Bytes key, final long from) { + if (key == null) { + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + TIMESTAMP_SIZE) + .put(TIME_FIRST_PREFIX) + .putLong(from) + .array()); + } + + return Bytes.wrap(ByteBuffer.allocate(PREFIX_SIZE + 2 * TIMESTAMP_SIZE + key.get().length) + .put(TIME_FIRST_PREFIX) + .putLong(from) + .putLong(0L) + .put(key.get()) + .array()); + } + + /** + * + * @param key the key in the range + * @param to the latest start time + * @return + */ + @Override + public Bytes upperRangeFixedSize(final Bytes key, final long to) { + return toBinary(key, to, Long.MAX_VALUE); + } + + /** + * + * @param key the key in the range + * @param from the earliest end timestamp in the range + * @return + */ + @Override + public Bytes lowerRangeFixedSize(final Bytes key, final long from) { + return toBinary(key, 0, Math.max(0, from)); + } + + @Override + public long segmentTimestamp(final Bytes key) { + return extractEndTimestamp(key.get()); + } + + @Override + public HasNextCondition hasNextCondition(final Bytes binaryKeyFrom, + final Bytes binaryKeyTo, final long from, final long to, final boolean forward) { + return iterator -> { + while (iterator.hasNext()) { + final Bytes bytes = iterator.peekNextKey(); + final byte prefix = extractPrefix(bytes.get()); + + if (prefix != TIME_FIRST_PREFIX) { + return false; + } + + final Windowed<Bytes> windowedKey = from(bytes); + final long endTime = windowedKey.window().end(); + final long startTime = windowedKey.window().start(); + + // We can return false directly here since keys are sorted by end time and if + // we get time smaller than `from`, there won't be time within range. + if (!forward && endTime < from) { + return false; + } + + if ((binaryKeyFrom == null || windowedKey.key().compareTo(binaryKeyFrom) >= 0) + && (binaryKeyTo == null || windowedKey.key().compareTo(binaryKeyTo) <= 0) + && endTime >= from && startTime <= to) { + return true; + } + iterator.next(); + } + return false; + }; + } + + @Override + public <S extends Segment> List<S> segmentsToSearch(final Segments<S> segments, + final long from, + final long to, + final boolean forward) { + return segments.segments(from, Long.MAX_VALUE, forward); + } + + static long extractStartTimestamp(final byte[] binaryKey) { + return ByteBuffer.wrap(binaryKey).getLong(PREFIX_SIZE + TIMESTAMP_SIZE); + } + + static long extractEndTimestamp(final byte[] binaryKey) { + return ByteBuffer.wrap(binaryKey).getLong(PREFIX_SIZE); + } + + private static <K> K extractKey(final byte[] binaryKey, + final Deserializer<K> deserializer, + final String topic) { + return deserializer.deserialize(topic, extractKeyBytes(binaryKey)); + } + + static byte[] extractKeyBytes(final byte[] binaryKey) { + final byte[] bytes = new byte[binaryKey.length - 2 * TIMESTAMP_SIZE - PREFIX_SIZE]; + System.arraycopy(binaryKey, PREFIX_SIZE + 2 * TIMESTAMP_SIZE, bytes, 0, bytes.length); + return bytes; + } + + static Window extractWindow(final byte[] binaryKey) { + final ByteBuffer buffer = ByteBuffer.wrap(binaryKey); + final long start = buffer.getLong(PREFIX_SIZE + TIMESTAMP_SIZE); + final long end = buffer.getLong(PREFIX_SIZE); + return new SessionWindow(start, end); + } + + public static Windowed<Bytes> from(final Bytes bytesKey) { + final byte[] binaryKey = bytesKey.get(); + final Window window = extractWindow(binaryKey); + return new Windowed<>(Bytes.wrap(extractKeyBytes(binaryKey)), window); + } + + public static <K> Windowed<K> from(final byte[] binaryKey, + final Deserializer<K> keyDeserializer, + final String topic) { + final K key = extractKey(binaryKey, keyDeserializer, topic); + final Window window = extractWindow(binaryKey); + return new Windowed<>(key, window); + } + + public static <K> byte[] toBinary(final Windowed<K> sessionKey, + final Serializer<K> serializer, + final String topic) { + final byte[] bytes = serializer.serialize(topic, sessionKey.key()); + return toBinary(Bytes.wrap(bytes), sessionKey.window().start(), sessionKey.window().end()).get(); + } + + public static Bytes toBinary(final Windowed<Bytes> sessionKey) { + return toBinary(sessionKey.key(), sessionKey.window().start(), sessionKey.window().end()); + } + + public static Bytes toBinary(final Bytes key, + final long startTime, + final long endTime) { + final byte[] bytes = key.get(); + final ByteBuffer buf = ByteBuffer.allocate(PREFIX_SIZE + bytes.length + 2 * TIMESTAMP_SIZE) + .put(TIME_FIRST_PREFIX) + .putLong(endTime) + .putLong(startTime) + .put(bytes); + return Bytes.wrap(buf.array()); + } + + public static byte[] fromNonPrefixSessionKey(final byte[] binaryKey) { Review comment: SGTM! -- This is an automated message from the Apache Git Service. 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