| // 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.impala.catalog; |
| |
| import java.util.Map; |
| import java.util.concurrent.ConcurrentHashMap; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import com.google.common.base.Preconditions; |
| import com.google.common.base.Strings; |
| |
| // A log of topic update information for each catalog object. An entry is added to |
| // the log when a catalog object is processed (added/removed/skipped) in a topic |
| // update and it is replaced every time the catalog object is processed in a |
| // topic update. |
| // |
| // To prevent the log from growing indefinitely, the oldest entries |
| // (in terms of last topic update that processed the associated catalog objects) are |
| // garbage collected every TOPIC_UPDATE_LOG_GC_FREQUENCY topic updates. That will cause |
| // entries of deleted catalog objects or entries of objects that haven't been processed |
| // by the catalog for at least TOPIC_UPDATE_LOG_GC_FREQUENCY updates to be removed from |
| // the log. |
| public class TopicUpdateLog { |
| private static final Logger LOG = LoggerFactory.getLogger(TopicUpdateLog.class); |
| // Frequency at which the entries of the topic update log are garbage collected. |
| // An entry may survive for (2 * TOPIC_UPDATE_LOG_GC_FREQUENCY) - 1 topic updates. |
| private final static int TOPIC_UPDATE_LOG_GC_FREQUENCY = 1000; |
| |
| // Number of topic updates left to trigger a gc of topic update log entries. |
| private int numTopicUpdatesToGc_ = TOPIC_UPDATE_LOG_GC_FREQUENCY; |
| |
| // In the next gc cycle of topic update log entries, all the entries that were last |
| // added to a topic update with version less than or equal to |
| // 'oldestTopicUpdateToGc_' are removed from the update log. |
| private long oldestTopicUpdateToGc_ = -1; |
| |
| // Represents an entry in the topic update log. A topic update log entry is |
| // associated with a catalog object and stores information about the last topic update |
| // that processed that object. |
| public static class Entry { |
| // Number of times the entry has skipped a topic update. |
| private final int numSkippedUpdates_; |
| // Last version of the corresponding catalog object that was added to a topic |
| // update. -1 if the object was never added to a topic update. |
| private final long lastSentVersion_; |
| // Version of the last topic update to include the corresponding catalog object. |
| // -1 if the object was never added to a topic update. |
| private final long lastSentTopicUpdate_; |
| |
| Entry() { |
| numSkippedUpdates_ = 0; |
| lastSentVersion_ = -1; |
| lastSentTopicUpdate_ = -1; |
| } |
| |
| Entry(int numSkippedUpdates, long lastSentVersion, long lastSentCatalogUpdate) { |
| numSkippedUpdates_ = numSkippedUpdates; |
| lastSentVersion_ = lastSentVersion; |
| lastSentTopicUpdate_ = lastSentCatalogUpdate; |
| } |
| |
| public int getNumSkippedTopicUpdates() { return numSkippedUpdates_; } |
| public long getLastSentVersion() { return lastSentVersion_; } |
| public long getLastSentCatalogUpdate() { return lastSentTopicUpdate_; } |
| |
| @Override |
| public boolean equals(Object other) { |
| if (this.getClass() != other.getClass()) return false; |
| Entry entry = (Entry) other; |
| return numSkippedUpdates_ == entry.getNumSkippedTopicUpdates() |
| && lastSentVersion_ == entry.getLastSentVersion() |
| && lastSentTopicUpdate_ == entry.getLastSentCatalogUpdate(); |
| } |
| } |
| |
| // Entries in the topic update log stored as a map of catalog object keys to |
| // Entry objects. |
| private final Map<String, Entry> topicLogEntries_ = |
| new ConcurrentHashMap<>(); |
| |
| /** |
| * Garbage-collects topic update log entries. These are entries that haven't been |
| * added to any of the last TOPIC_UPDATE_LOG_GC_FREQUENCY topic updates. |
| */ |
| public void garbageCollectUpdateLogEntries(long lastTopicUpdateVersion) { |
| if (oldestTopicUpdateToGc_ == -1) { |
| oldestTopicUpdateToGc_ = lastTopicUpdateVersion; |
| return; |
| } |
| if (numTopicUpdatesToGc_ == 0) { |
| LOG.info("Topic update log GC started. GC-ing topics with versions " + |
| "<= {}", oldestTopicUpdateToGc_); |
| Preconditions.checkState(oldestTopicUpdateToGc_ > 0); |
| int numEntriesRemoved = 0; |
| for (Map.Entry<String, Entry> entry: |
| topicLogEntries_.entrySet()) { |
| if (entry.getValue().getLastSentVersion() == -1) continue; |
| if (entry.getValue().getLastSentCatalogUpdate() <= oldestTopicUpdateToGc_) { |
| if (topicLogEntries_.remove(entry.getKey(), entry.getValue())) { |
| ++numEntriesRemoved; |
| } |
| } |
| } |
| numTopicUpdatesToGc_ = TOPIC_UPDATE_LOG_GC_FREQUENCY; |
| oldestTopicUpdateToGc_ = lastTopicUpdateVersion; |
| LOG.info("Topic update log GC finished. Removed {} entries.", |
| numEntriesRemoved); |
| } else { |
| --numTopicUpdatesToGc_; |
| } |
| } |
| |
| public void add(String catalogObjectKey, Entry logEntry) { |
| Preconditions.checkState(!Strings.isNullOrEmpty(catalogObjectKey)); |
| Preconditions.checkNotNull(logEntry); |
| topicLogEntries_.put(catalogObjectKey, logEntry); |
| } |
| |
| public Entry get(String catalogObjectKey) { |
| Preconditions.checkState(!Strings.isNullOrEmpty(catalogObjectKey)); |
| return topicLogEntries_.get(catalogObjectKey); |
| } |
| |
| // Returns the topic update log entry for the catalog object with key |
| // 'catalogObjectKey'. If the key does not exist, a newly constructed log entry is |
| // returned. |
| public Entry getOrCreateLogEntry(String catalogObjectKey) { |
| Preconditions.checkState(!Strings.isNullOrEmpty(catalogObjectKey)); |
| Entry entry = topicLogEntries_.get(catalogObjectKey); |
| if (entry == null) entry = new Entry(); |
| return entry; |
| } |
| } |
| |