Java tutorial
/* * 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.jackrabbit.oak.plugins.document.mongo; import java.util.List; import java.util.Set; import com.google.common.base.Function; import com.google.common.base.Joiner; import com.google.common.base.StandardSystemProperty; import com.google.common.collect.ImmutableList; import com.google.common.collect.Iterables; import com.mongodb.BasicDBObject; import com.mongodb.DBCollection; import com.mongodb.DBCursor; import com.mongodb.DBObject; import com.mongodb.QueryBuilder; import com.mongodb.ReadPreference; import org.apache.jackrabbit.oak.plugins.document.Document; import org.apache.jackrabbit.oak.plugins.document.NodeDocument; import org.apache.jackrabbit.oak.plugins.document.SplitDocumentCleanUp; import org.apache.jackrabbit.oak.plugins.document.VersionGCSupport; import org.apache.jackrabbit.oak.plugins.document.VersionGarbageCollector.VersionGCStats; import org.apache.jackrabbit.oak.plugins.document.util.CloseableIterable; import org.slf4j.Logger; import org.slf4j.LoggerFactory; import static com.google.common.collect.Iterables.transform; import static com.mongodb.QueryBuilder.start; import static org.apache.jackrabbit.oak.plugins.document.Collection.NODES; import static org.apache.jackrabbit.oak.plugins.document.NodeDocument.SplitDocType; /** * Mongo specific version of VersionGCSupport which uses mongo queries * to fetch required NodeDocuments * * <p>Version collection involves looking into old record and mostly unmodified * documents. In such case read from secondaries are preferred</p> */ public class MongoVersionGCSupport extends VersionGCSupport { private static final Logger LOG = LoggerFactory.getLogger(MongoVersionGCSupport.class); private final MongoDocumentStore store; /** * Disables the index hint sent to MongoDB. */ private final boolean disableIndexHint = Boolean.getBoolean("oak.mongo.disableVersionGCIndexHint"); public MongoVersionGCSupport(MongoDocumentStore store) { super(store); this.store = store; } @Override public CloseableIterable<NodeDocument> getPossiblyDeletedDocs(final long lastModifiedTime) { //_deletedOnce == true && _modified < lastModifiedTime DBObject query = start(NodeDocument.DELETED_ONCE).is(Boolean.TRUE).put(NodeDocument.MODIFIED_IN_SECS) .lessThan(NodeDocument.getModifiedInSecs(lastModifiedTime)).get(); DBCursor cursor = getNodeCollection().find(query).setReadPreference(ReadPreference.secondaryPreferred()); if (!disableIndexHint) { cursor.hint(new BasicDBObject(NodeDocument.DELETED_ONCE, 1)); } return CloseableIterable.wrap(transform(cursor, new Function<DBObject, NodeDocument>() { @Override public NodeDocument apply(DBObject input) { return store.convertFromDBObject(NODES, input); } }), cursor); } @Override protected SplitDocumentCleanUp createCleanUp(Set<SplitDocType> gcTypes, long oldestRevTimeStamp, VersionGCStats stats) { return new MongoSplitDocCleanUp(gcTypes, oldestRevTimeStamp, stats); } @Override protected Iterable<NodeDocument> identifyGarbage(final Set<SplitDocType> gcTypes, final long oldestRevTimeStamp) { return transform(getNodeCollection().find(createQuery(gcTypes, oldestRevTimeStamp)), new Function<DBObject, NodeDocument>() { @Override public NodeDocument apply(DBObject input) { return store.convertFromDBObject(NODES, input); } }); } private DBObject createQuery(Set<SplitDocType> gcTypes, long oldestRevTimeStamp) { //OR condition has to be first as we have a index for that //((type == DEFAULT_NO_CHILD || type == PROP_COMMIT_ONLY ..) && _sdMaxRevTime < oldestRevTimeStamp(in secs) QueryBuilder orClause = start(); for (SplitDocType type : gcTypes) { orClause.or(start(NodeDocument.SD_TYPE).is(type.typeCode()).get()); } return start().and(orClause.get(), start(NodeDocument.SD_MAX_REV_TIME_IN_SECS) .lessThan(NodeDocument.getModifiedInSecs(oldestRevTimeStamp)).get()).get(); } private void logSplitDocIdsTobeDeleted(DBObject query) { // Fetch only the id final BasicDBObject keys = new BasicDBObject(Document.ID, 1); List<String> ids; DBCursor cursor = getNodeCollection().find(query, keys) .setReadPreference(store.getConfiguredReadPreference(NODES)); try { ids = ImmutableList.copyOf(Iterables.transform(cursor, new Function<DBObject, String>() { @Override public String apply(DBObject input) { return (String) input.get(Document.ID); } })); } finally { cursor.close(); } StringBuilder sb = new StringBuilder("Split documents with following ids were deleted as part of GC \n"); Joiner.on(StandardSystemProperty.LINE_SEPARATOR.value()).appendTo(sb, ids); LOG.debug(sb.toString()); } private DBCollection getNodeCollection() { return store.getDBCollection(NODES); } private class MongoSplitDocCleanUp extends SplitDocumentCleanUp { protected final Set<SplitDocType> gcTypes; protected final long oldestRevTimeStamp; protected MongoSplitDocCleanUp(Set<SplitDocType> gcTypes, long oldestRevTimeStamp, VersionGCStats stats) { super(MongoVersionGCSupport.this.store, stats, identifyGarbage(gcTypes, oldestRevTimeStamp)); this.gcTypes = gcTypes; this.oldestRevTimeStamp = oldestRevTimeStamp; } @Override protected int deleteSplitDocuments() { DBObject query = createQuery(gcTypes, oldestRevTimeStamp); if (LOG.isDebugEnabled()) { //if debug level logging is on then determine the id of documents to be deleted //and log them logSplitDocIdsTobeDeleted(query); } return getNodeCollection().remove(query).getN(); } } }