swamirishi commented on code in PR #5619: URL: https://github.com/apache/ozone/pull/5619#discussion_r1399626254
########## hadoop-ozone/ozone-manager/src/main/java/org/apache/hadoop/ozone/om/ListIterator.java: ########## @@ -0,0 +1,355 @@ +/* + * 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 + * <p> + * http://www.apache.org/licenses/LICENSE-2.0 + * <p> + * 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.hadoop.ozone.om; + +import org.apache.commons.lang3.StringUtils; +import org.apache.hadoop.hdds.utils.db.CopyObject; +import org.apache.hadoop.hdds.utils.db.Table; +import org.apache.hadoop.hdds.utils.db.TableIterator; +import org.apache.hadoop.hdds.utils.db.cache.CacheKey; +import org.apache.hadoop.hdds.utils.db.cache.CacheValue; +import org.apache.hadoop.ozone.om.helpers.BucketLayout; + +import java.io.Closeable; +import java.io.IOException; +import java.util.ArrayList; +import java.util.Comparator; +import java.util.Iterator; +import java.util.Map; +import java.util.NoSuchElementException; +import java.util.PriorityQueue; +import java.util.TreeMap; + +import static org.apache.hadoop.ozone.om.lock.OzoneManagerLock.Resource.BUCKET_LOCK; + +/** + * Common class to do listing of resources after merging + * rocksDB table cache & actual table. + */ +public class ListIterator { + + /** + * Interface for iteration of Heap Entries. + */ + public interface ClosableIterator extends Iterator<HeapEntry>, Closeable { + + } + + /** + * Entry to be added to the heap. + */ + public static class HeapEntry implements Comparable<HeapEntry> { + private final int entryInteratorId; + private final String tableName; + private final String key; + private final Object value; + + HeapEntry(int entryInteratorId, String tableName, String key, + Object value) { + this.entryInteratorId = entryInteratorId; + this.tableName = tableName; + this.key = key; + this.value = value; + } + + public String getKey() { + return this.key; + } + + private int getEntryInteratorId() { + return this.entryInteratorId; + } + + public String getTableName() { + return tableName; + } + + public Object getValue() { + return value; + } + + public int compareTo(HeapEntry other) { + return Comparator.comparing(HeapEntry::getKey) + .thenComparing(HeapEntry::getEntryInteratorId).compare(this, other); + } + + public boolean equals(Object other) { + if (other == null) { + return false; + } + + if (!(other instanceof HeapEntry)) { + return false; + } + + + HeapEntry that = (HeapEntry) other; + return this.compareTo(that) == 0; + } + + public int hashCode() { + return key.hashCode(); + } + } + + /** + * Iterator for DB entries in a Dir and File Table. + */ + public static class RawIter<Value> implements + ClosableIterator { + private final int entryInteratorId; + private final String prefixKey; + private final TableIterator<String, + ? extends Table.KeyValue<String, Value>> tableIterator; + + private final Table<String, Value> table; + private HeapEntry currentKey; + + RawIter(int entryInteratorId, Table<String, Value> table, + String prefixKey, String startKey) throws IOException { + this.entryInteratorId = entryInteratorId; + this.table = table; + this.tableIterator = table.iterator(prefixKey); + this.prefixKey = prefixKey; + this.currentKey = null; + + // only seek for the start key if the start key is lexicographically + // after the prefix key. For example + // Prefix key = 1024/c, Start key = 1024/a + // then do not seek for the start key + // + // on the other hand, + // Prefix key = 1024/a, Start key = 1024/c + // then seek for the start key + if (!StringUtils.isBlank(startKey) && + startKey.compareTo(prefixKey) > 0) { + tableIterator.seek(startKey); + } + + getNextKey(); + } + + private void getNextKey() throws IOException { + while (tableIterator.hasNext() && currentKey == null) { + Table.KeyValue<String, Value> entry = tableIterator.next(); + String entryKey = entry.getKey(); + if (entryKey.startsWith(prefixKey)) { + if (!KeyManagerImpl.isKeyDeleted(entryKey, table)) { + currentKey = new HeapEntry(entryInteratorId, + table.getName(), entryKey, entry.getValue()); + } + } else { + // if the prefix key does not match, then break + // as the iterator is beyond the prefix. + break; + } + } + } + + public boolean hasNext() { + try { + getNextKey(); + } catch (Throwable t) { + throw new NoSuchElementException(); + } + return currentKey != null; + } + + public HeapEntry next() { + try { + getNextKey(); + } catch (Throwable t) { + throw new NoSuchElementException(); + } + HeapEntry ret = currentKey; + currentKey = null; + + return ret; + } + + public void close() throws IOException { + tableIterator.close(); + } + } + + /** + * Iterator for Cache entries in a Dir and File Table. + */ + public static class CacheIter<Value> + implements ClosableIterator { + private final Map<String, Value> cacheKeyMap; + + private final Iterator<Map.Entry<String, Value>> + cacheCreatedKeyIter; + private final Iterator<Map.Entry<CacheKey<String>, CacheValue<Value>>> + cacheIter; + private final String prefixKey; + private final String startKey; + private final String tableName; + + private final int entryInteratorId; + + CacheIter(int entryInteratorId, String tableName, + Iterator<Map.Entry<CacheKey<String>, + CacheValue<Value>>> cacheIter, String startKey, + String prefixKey) { + this.cacheKeyMap = new TreeMap<>(); + + this.cacheIter = cacheIter; + this.startKey = startKey; + this.prefixKey = prefixKey; + this.tableName = tableName; + this.entryInteratorId = entryInteratorId; + + getCacheValues(); + + cacheCreatedKeyIter = cacheKeyMap.entrySet().iterator(); + } + + private void getCacheValues() { + while (cacheIter.hasNext()) { + Map.Entry<CacheKey<String>, CacheValue<Value>> entry = + cacheIter.next(); + String cacheKey = entry.getKey().getCacheKey(); + Value cacheOmInfo = entry.getValue().getCacheValue(); + + // Copy cache value to local copy and work on it + if (cacheOmInfo instanceof CopyObject) { + cacheOmInfo = ((CopyObject<Value>) cacheOmInfo).copyObject(); + } + if (StringUtils.isBlank(startKey)) { + // startKey is null or empty, then the seekKeyInDB="1024/" + if (cacheKey.startsWith(prefixKey)) { + cacheKeyMap.put(cacheKey, cacheOmInfo); + } + } else { + // startKey not empty, then the seekKeyInDB="1024/b" and + // seekKeyInDBWithOnlyParentID = "1024/". This is to avoid case of + // parentID with "102444" cache entries. + // Here, it has to list all the keys after "1024/b" and requires >=0 + // string comparison. + if (cacheKey.startsWith(prefixKey) && + cacheKey.compareTo(startKey) >= 0) { + cacheKeyMap.put(cacheKey, cacheOmInfo); + } + } + } + } + + public boolean hasNext() { + return cacheCreatedKeyIter.hasNext(); + } + + public HeapEntry next() { + Map.Entry<String, Value> entry = cacheCreatedKeyIter.next(); + return new HeapEntry(this.entryInteratorId, this.tableName, + entry.getKey(), entry.getValue()); + } + + public void close() { + // Nothing to close here + } + } + + /** + * Implement lexicographical sorting of the file status by sorting file status + * across multiple lists. Each of these lists are sorted internally. + * + * This class implements sorted output by implementing a min heap based + * iterator where the initial element from each of sorted list is inserted. + * + * The least entry is removed and the next entry from the same list from + * which the entry is removed is added into the list. + * + * For example + * RawDir - a1, a3, a5, a7 + * RawFile - a2, a4, a6, a8 + * + * Min Heap is initially composed of {(a1, RawDir), (a2, RawFile)} + * THe least element is removed i.e a1 and then next entry from RawDir + * is inserted into minheap resulting in {(a2, RawFile), (a3, RawDir)} + * + * This process is repeated till both the lists are exhausted. + */ + public static class MinHeapIterator implements ClosableIterator { + private final PriorityQueue<HeapEntry> minHeap = new PriorityQueue<>(); + private final ArrayList<ClosableIterator> iterators = new ArrayList<>(); + + MinHeapIterator(OMMetadataManager omMetadataManager, String prefixKey, + BucketLayout bucketLayout, String startKey, + String volumeName, String bucketName) throws IOException { + + this(omMetadataManager, prefixKey, startKey, volumeName, + bucketName, omMetadataManager.getDirectoryTable(), + omMetadataManager.getKeyTable(bucketLayout)); + } + + MinHeapIterator(OMMetadataManager omMetadataManager, String prefixKey, + String startKey, String volumeName, String bucketName, + Table... tables) throws IOException { + omMetadataManager.getLock().acquireReadLock(BUCKET_LOCK, volumeName, + bucketName); + try { + int iteratorId = 0; + for (Table table : tables) { + iterators.add(new CacheIter<>(iteratorId, table.getName(), + table.cacheIterator(), startKey, prefixKey)); + iteratorId++; + iterators.add(new RawIter<>(iteratorId, + omMetadataManager.getDirectoryTable(), + prefixKey, startKey)); + iteratorId++; + } + } finally { + omMetadataManager.getLock().releaseReadLock(BUCKET_LOCK, volumeName, + bucketName); + } + + // Insert the element from each of the iterator + for (Iterator<HeapEntry> iter : iterators) { + if (iter.hasNext()) { + minHeap.add(iter.next()); + } + } + + } + + public boolean hasNext() { + return !minHeap.isEmpty(); + } + + public HeapEntry next() { + HeapEntry heapEntry = minHeap.remove(); + // remove the least element and + // reinsert the next element from the same iterator + Iterator<HeapEntry> iter = iterators.get(heapEntry.getEntryInteratorId()); Review Comment: yeah I guess there was a bug in the previous code as well. This was being used for listing keys & dirs for FSO buckets. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
