smiklosovic commented on code in PR #4399: URL: https://github.com/apache/cassandra/pull/4399#discussion_r2410953126
########## src/java/org/apache/cassandra/db/compression/CompressionDictionaryManager.java: ########## @@ -0,0 +1,346 @@ +/* + * 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.cassandra.db.compression; + +import java.nio.ByteBuffer; +import java.util.Map; +import javax.annotation.Nullable; + +import com.google.common.annotations.VisibleForTesting; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.cassandra.config.DatabaseDescriptor; +import org.apache.cassandra.db.ColumnFamilyStore; +import org.apache.cassandra.db.compression.ICompressionDictionaryTrainer.TrainingStatus; +import org.apache.cassandra.schema.CompressionParams; +import org.apache.cassandra.schema.SystemDistributedKeyspace; +import org.apache.cassandra.utils.MBeanWrapper; +import org.apache.cassandra.utils.MBeanWrapper.OnException; + +public class CompressionDictionaryManager implements CompressionDictionaryManagerMBean, + ICompressionDictionaryCache, + ICompressionDictionaryEventHandler, + AutoCloseable +{ + private static final Logger logger = LoggerFactory.getLogger(CompressionDictionaryManager.class); + + private final String keyspaceName; + private final String tableName; + private volatile boolean mbeanRegistered; + private volatile boolean isEnabled; + + // Components + private final ICompressionDictionaryEventHandler eventHandler; + private final ICompressionDictionaryCache cache; + private final ICompressionDictionaryScheduler scheduler; + private ICompressionDictionaryTrainer trainer = null; + + public CompressionDictionaryManager(ColumnFamilyStore columnFamilyStore, boolean registerBookkeeping) + { + this.keyspaceName = columnFamilyStore.keyspace.getName(); + this.tableName = columnFamilyStore.getTableName(); + + this.isEnabled = columnFamilyStore.metadata().params.compression.isDictionaryCompressionEnabled(); + this.cache = new CompressionDictionaryCache(); + this.eventHandler = new CompressionDictionaryEventHandler(columnFamilyStore, cache); + this.scheduler = new CompressionDictionaryScheduler(keyspaceName, tableName, cache, isEnabled); + if (isEnabled) + { + // Initialize components + this.trainer = ICompressionDictionaryTrainer.create(keyspaceName, tableName, + columnFamilyStore.metadata().params.compression, + createTrainingConfig()); + trainer.setDictionaryTrainedListener(this::handleNewDictionary); + + scheduler.scheduleRefreshTask(); + + trainer.start(false); + } + + if (registerBookkeeping) + { + MBeanWrapper.instance.registerMBean(this, mbeanName(keyspaceName, tableName)); + } + mbeanRegistered = registerBookkeeping; + } + + static String mbeanName(String keyspaceName, String tableName) + { + return "org.apache.cassandra.db.compression:type=CompressionDictionaryManager" + + ",keyspace=" + keyspaceName + ",table=" + tableName; + } + + public boolean isEnabled() + { + return isEnabled; + } + + /** + * Reloads dictionary management configuration when compression parameters change. + * This method enables or disables dictionary compression based on the new parameters, + * and properly manages the lifecycle of training and refresh tasks. + * + * @param newParams the new compression parameters to apply + */ + public synchronized void maybeReloadFromSchema(CompressionParams newParams) + { + this.isEnabled = newParams.isDictionaryCompressionEnabled(); + scheduler.setEnabled(isEnabled); + if (isEnabled) + { + // Check if we need a new trainer due to compression parameter changes + boolean needsNewTrainer = shouldCreateNewTrainer(newParams); + + if (needsNewTrainer) + { + // The manual training should be cancelled if a new trainer is needed + scheduler.cancelManualTraining(); + // Close existing trainer and create a new one + if (trainer != null) + { + try + { + trainer.close(); + } + catch (Exception e) + { + logger.warn("Failed to close existing trainer for {}.{}", keyspaceName, tableName, e); + } + } + + trainer = ICompressionDictionaryTrainer.create(keyspaceName, tableName, newParams, createTrainingConfig()); + trainer.setDictionaryTrainedListener(this::handleNewDictionary); + } + + scheduler.scheduleRefreshTask(); + + // Start trainer if it exists + if (trainer != null) + { + trainer.start(false); + } + return; + } + + // Clean up when dictionary compression is disabled + try + { + close(); + } + catch (Exception e) + { + logger.warn("Failed to close CompressionDictionaryManager on disabling " + + "dictionary-based compression for table {}.{}", keyspaceName, tableName); + } + } + + /** + * Adds a sample to the dictionary trainer for learning compression patterns. + * Samples are randomly selected to avoid bias and improve dictionary quality. + * + * @param sample the sample data to potentially add for training + */ + public void addSample(ByteBuffer sample) + { + ICompressionDictionaryTrainer dictionaryTrainer = trainer; + if (dictionaryTrainer != null && dictionaryTrainer.shouldSample()) + { + dictionaryTrainer.addSample(sample); + } + } + + @Nullable + @Override + public CompressionDictionary getCurrent() + { + return cache.getCurrent(); + } + + @Override + public CompressionDictionary get(CompressionDictionary.DictId dictId) + { + return cache.get(dictId); + } + + @Override + public void add(CompressionDictionary compressionDictionary) + { + cache.add(compressionDictionary); + } + + @Override + public void setCurrentIfNewer(@Nullable CompressionDictionary dictionary) + { + cache.setCurrentIfNewer(dictionary); + } + + @Override + public void onNewDictionaryTrained(long dictionaryId) + { + eventHandler.onNewDictionaryTrained(dictionaryId); + } + + @Override + public void onNewDictionaryAvailable(long dictionaryId) + { + eventHandler.onNewDictionaryAvailable(dictionaryId); + } + + @Override + public synchronized void train(Map<String, String> options) + { + // Validate table supports dictionary compression + if (!isEnabled) + { + throw new IllegalArgumentException("Table " + keyspaceName + '.' + tableName + " does not support dictionary compression"); + } + + if (trainer == null) + { + throw new IllegalStateException("Dictionary trainer is not available for table " + keyspaceName + '.' + tableName); + } + + // Parse and validate training options + ManualTrainingOptions trainingOptions = ManualTrainingOptions.fromStringMap(options); + + trainer.start(true); + scheduler.scheduleManualTraining(trainingOptions, trainer); Review Comment: we would not actually _scheduled_ anything in that method if trainer is no-op instance. ########## src/java/org/apache/cassandra/db/compression/CompressionDictionaryManager.java: ########## @@ -0,0 +1,346 @@ +/* + * 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.cassandra.db.compression; + +import java.nio.ByteBuffer; +import java.util.Map; +import javax.annotation.Nullable; + +import com.google.common.annotations.VisibleForTesting; +import org.slf4j.Logger; +import org.slf4j.LoggerFactory; + +import org.apache.cassandra.config.DatabaseDescriptor; +import org.apache.cassandra.db.ColumnFamilyStore; +import org.apache.cassandra.db.compression.ICompressionDictionaryTrainer.TrainingStatus; +import org.apache.cassandra.schema.CompressionParams; +import org.apache.cassandra.schema.SystemDistributedKeyspace; +import org.apache.cassandra.utils.MBeanWrapper; +import org.apache.cassandra.utils.MBeanWrapper.OnException; + +public class CompressionDictionaryManager implements CompressionDictionaryManagerMBean, + ICompressionDictionaryCache, + ICompressionDictionaryEventHandler, + AutoCloseable +{ + private static final Logger logger = LoggerFactory.getLogger(CompressionDictionaryManager.class); + + private final String keyspaceName; + private final String tableName; + private volatile boolean mbeanRegistered; + private volatile boolean isEnabled; + + // Components + private final ICompressionDictionaryEventHandler eventHandler; + private final ICompressionDictionaryCache cache; + private final ICompressionDictionaryScheduler scheduler; + private ICompressionDictionaryTrainer trainer = null; + + public CompressionDictionaryManager(ColumnFamilyStore columnFamilyStore, boolean registerBookkeeping) + { + this.keyspaceName = columnFamilyStore.keyspace.getName(); + this.tableName = columnFamilyStore.getTableName(); + + this.isEnabled = columnFamilyStore.metadata().params.compression.isDictionaryCompressionEnabled(); + this.cache = new CompressionDictionaryCache(); + this.eventHandler = new CompressionDictionaryEventHandler(columnFamilyStore, cache); + this.scheduler = new CompressionDictionaryScheduler(keyspaceName, tableName, cache, isEnabled); + if (isEnabled) + { + // Initialize components + this.trainer = ICompressionDictionaryTrainer.create(keyspaceName, tableName, + columnFamilyStore.metadata().params.compression, + createTrainingConfig()); + trainer.setDictionaryTrainedListener(this::handleNewDictionary); + + scheduler.scheduleRefreshTask(); + + trainer.start(false); + } + + if (registerBookkeeping) + { + MBeanWrapper.instance.registerMBean(this, mbeanName(keyspaceName, tableName)); + } + mbeanRegistered = registerBookkeeping; + } + + static String mbeanName(String keyspaceName, String tableName) + { + return "org.apache.cassandra.db.compression:type=CompressionDictionaryManager" + + ",keyspace=" + keyspaceName + ",table=" + tableName; + } + + public boolean isEnabled() + { + return isEnabled; + } + + /** + * Reloads dictionary management configuration when compression parameters change. + * This method enables or disables dictionary compression based on the new parameters, + * and properly manages the lifecycle of training and refresh tasks. + * + * @param newParams the new compression parameters to apply + */ + public synchronized void maybeReloadFromSchema(CompressionParams newParams) + { + this.isEnabled = newParams.isDictionaryCompressionEnabled(); + scheduler.setEnabled(isEnabled); + if (isEnabled) + { + // Check if we need a new trainer due to compression parameter changes + boolean needsNewTrainer = shouldCreateNewTrainer(newParams); + + if (needsNewTrainer) + { + // The manual training should be cancelled if a new trainer is needed + scheduler.cancelManualTraining(); + // Close existing trainer and create a new one + if (trainer != null) + { + try + { + trainer.close(); + } + catch (Exception e) + { + logger.warn("Failed to close existing trainer for {}.{}", keyspaceName, tableName, e); + } + } + + trainer = ICompressionDictionaryTrainer.create(keyspaceName, tableName, newParams, createTrainingConfig()); + trainer.setDictionaryTrainedListener(this::handleNewDictionary); + } + + scheduler.scheduleRefreshTask(); + + // Start trainer if it exists + if (trainer != null) + { + trainer.start(false); + } + return; + } + + // Clean up when dictionary compression is disabled + try + { + close(); + } + catch (Exception e) + { + logger.warn("Failed to close CompressionDictionaryManager on disabling " + + "dictionary-based compression for table {}.{}", keyspaceName, tableName); + } + } + + /** + * Adds a sample to the dictionary trainer for learning compression patterns. + * Samples are randomly selected to avoid bias and improve dictionary quality. + * + * @param sample the sample data to potentially add for training + */ + public void addSample(ByteBuffer sample) + { + ICompressionDictionaryTrainer dictionaryTrainer = trainer; + if (dictionaryTrainer != null && dictionaryTrainer.shouldSample()) + { + dictionaryTrainer.addSample(sample); + } + } + + @Nullable + @Override + public CompressionDictionary getCurrent() + { + return cache.getCurrent(); + } + + @Override + public CompressionDictionary get(CompressionDictionary.DictId dictId) + { + return cache.get(dictId); + } + + @Override + public void add(CompressionDictionary compressionDictionary) + { + cache.add(compressionDictionary); + } + + @Override + public void setCurrentIfNewer(@Nullable CompressionDictionary dictionary) + { + cache.setCurrentIfNewer(dictionary); + } + + @Override + public void onNewDictionaryTrained(long dictionaryId) + { + eventHandler.onNewDictionaryTrained(dictionaryId); + } + + @Override + public void onNewDictionaryAvailable(long dictionaryId) + { + eventHandler.onNewDictionaryAvailable(dictionaryId); + } + + @Override + public synchronized void train(Map<String, String> options) + { + // Validate table supports dictionary compression + if (!isEnabled) + { + throw new IllegalArgumentException("Table " + keyspaceName + '.' + tableName + " does not support dictionary compression"); + } + + if (trainer == null) + { + throw new IllegalStateException("Dictionary trainer is not available for table " + keyspaceName + '.' + tableName); + } + + // Parse and validate training options + ManualTrainingOptions trainingOptions = ManualTrainingOptions.fromStringMap(options); + + trainer.start(true); + scheduler.scheduleManualTraining(trainingOptions, trainer); + } + + @Override + public String getTrainingStatus() + { + ICompressionDictionaryTrainer dictionaryTrainer = trainer; + if (dictionaryTrainer == null) + { + return TrainingStatus.NOT_STARTED.toString(); + } + return dictionaryTrainer.getTrainingStatus().toString(); Review Comment: `getTrainingStatus` on no-op trainer would always return `NOT_STARTED`. -- This is an automated message from the Apache Git Service. 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