Merge "Caching of changes"

Documentation/config-gerrit.txt

@@ -476,6 +476,15 @@ for the client to use as potential delta bases.  Push over smart HTTP
 requires two HTTP requests, and this cache tries to carry state from
 the first request into the second to ensure it can complete.
 
+cache `"changes"`::
++
+Each item caches all changes tied to one project. Default size
+is 1024, which means all changes for up to 1024 projects can be held
+in the cache. This cache should probably be disabled in a multi-master
+setup where change updates are not communicated between servers. The
+cache should be flushed whenever the database changes table is modified
+outside of gerrit.
+
 cache `"diff"`::
 +
 Each item caches the differences between two commits, at both the

gerrit-httpd/src/main/java/com/google/gerrit/httpd/GitOverHttpServlet.java

@@ -23,6 +23,7 @@ import com.google.gerrit.server.AnonymousUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.cache.CacheModule;
 import com.google.gerrit.server.git.AsyncReceiveCommits;
+import com.google.gerrit.server.git.ChangeCache;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.ReceiveCommits;
 import com.google.gerrit.server.git.TagCache;
@@ -198,11 +199,13 @@ public class GitOverHttpServlet extends GitServlet {
   static class UploadFilter implements Filter {
     private final Provider<ReviewDb> db;
     private final TagCache tagCache;
+    private final ChangeCache changeCache;
 
     @Inject
-    UploadFilter(Provider<ReviewDb> db, TagCache tagCache) {
+    UploadFilter(Provider<ReviewDb> db, TagCache tagCache, ChangeCache changeCache) {
       this.db = db;
       this.tagCache = tagCache;
+      this.changeCache = changeCache;
     }
 
     @Override
@@ -221,7 +224,7 @@ public class GitOverHttpServlet extends GitServlet {
       }
 
       if (!pc.allRefsAreVisible()) {
-        up.setAdvertiseRefsHook(new VisibleRefFilter(tagCache, repo, pc, db.get(), true));
+        up.setAdvertiseRefsHook(new VisibleRefFilter(tagCache, changeCache, repo, pc, db.get(), true));
       }
 
       next.doFilter(request, response);

gerrit-server/src/main/java/com/google/gerrit/server/config/GerritGlobalModule.java

@@ -52,6 +52,7 @@ import com.google.gerrit.server.auth.ldap.LdapModule;
 import com.google.gerrit.server.cache.CacheRemovalListener;
 import com.google.gerrit.server.events.EventFactory;
 import com.google.gerrit.server.extensions.events.GitReferenceUpdated;
+import com.google.gerrit.server.git.ChangeCache;
 import com.google.gerrit.server.git.ChangeMergeQueue;
 import com.google.gerrit.server.git.GitModule;
 import com.google.gerrit.server.git.MergeQueue;
@@ -125,6 +126,8 @@ public class GerritGlobalModule extends FactoryModule {
     install(ProjectCacheImpl.module());
     install(SectionSortCache.module());
     install(TagCache.module());
+    install(ChangeCache.module());
+
     install(new AccessControlModule());
     install(new GitModule());
     install(new PrologModule());
@@ -176,6 +179,7 @@ public class GerritGlobalModule extends FactoryModule {
     DynamicSet.setOf(binder(), CacheRemovalListener.class);
     DynamicSet.setOf(binder(), GitReferenceUpdatedListener.class);
     DynamicSet.setOf(binder(), NewProjectCreatedListener.class);
+    DynamicSet.bind(binder(), GitReferenceUpdatedListener.class).to(ChangeCache.class);
 
     bind(AnonymousUser.class);
   }

gerrit-server/src/main/java/com/google/gerrit/server/git/ChangeCache.java

@@ -0,0 +1,101 @@
+// Copyright (C) 2012 The Android Open Source Project
+//
+// Licensed 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 com.google.gerrit.server.git;
+
+package com.google.gerrit.server.git;
+
+import com.google.common.cache.CacheLoader;
+import com.google.common.cache.LoadingCache;
+import com.google.gerrit.extensions.events.GitReferenceUpdatedListener;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Project;
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.cache.CacheModule;
+import com.google.gwtorm.server.SchemaFactory;
+import com.google.inject.Inject;
+import com.google.inject.Module;
+import com.google.inject.Singleton;
+import com.google.inject.TypeLiteral;
+import com.google.inject.name.Named;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.Collections;
+import java.util.List;
+import java.util.concurrent.ExecutionException;
+
+@Singleton
+public class ChangeCache implements GitReferenceUpdatedListener {
+  private static final Logger log =
+      LoggerFactory.getLogger(ChangeCache.class);
+  private static final String ID_CACHE = "changes";
+
+  public static Module module() {
+    return new CacheModule() {
+      @Override
+      protected void configure() {
+        cache(ID_CACHE,
+            Project.NameKey.class,
+            new TypeLiteral<List<Change>>() {})
+          .maximumWeight(1024)
+          .loader(Loader.class);
+      }
+    };
+  }
+
+  private final LoadingCache<Project.NameKey, List<Change>> cache;
+
+  @Inject
+  ChangeCache(@Named(ID_CACHE) LoadingCache<Project.NameKey, List<Change>> cache) {
+    this.cache = cache;
+  }
+
+  List<Change> get(Project.NameKey name) {
+    try {
+      return cache.get(name);
+    } catch (ExecutionException e) {
+      log.warn("Cannot fetch changes for " + name, e);
+      return Collections.emptyList();
+    }
+  }
+
+  @Override
+  public void onGitReferenceUpdated(GitReferenceUpdatedListener.Event event) {
+    for (GitReferenceUpdatedListener.Update u : event.getUpdates()) {
+      if (u.getRefName().startsWith("refs/changes/")) {
+        cache.invalidate(new Project.NameKey(event.getProjectName()));
+        break;
+      }
+    }
+  }
+
+  static class Loader extends CacheLoader<Project.NameKey, List<Change>> {
+    private final SchemaFactory<ReviewDb> schema;
+
+    @Inject
+    Loader(SchemaFactory<ReviewDb> schema) {
+      this.schema = schema;
+    }
+
+    @Override
+    public List<Change> load(Project.NameKey key) throws Exception {
+      final ReviewDb db = schema.open();
+      try {
+        return Collections.unmodifiableList(db.changes().byProject(key).toList());
+      } finally {
+        db.close();
+      }
+    }
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/git/ReceiveCommits.java

@@ -252,6 +252,7 @@ public class ReceiveCommits {
   private final PersonIdent gerritIdent;
   private final TrackingFooters trackingFooters;
   private final TagCache tagCache;
+  private final ChangeCache changeCache;
   private final WorkQueue workQueue;
   private final ListeningExecutorService changeUpdateExector;
   private final RequestScopePropagator requestScopePropagator;
@@ -302,6 +303,7 @@ public class ReceiveCommits {
       final ProjectCache projectCache,
       final GitRepositoryManager repoManager,
       final TagCache tagCache,
+      final ChangeCache changeCache,
       @CanonicalWebUrl @Nullable final String canonicalWebUrl,
       @GerritPersonIdent final PersonIdent gerritIdent,
       final TrackingFooters trackingFooters,
@@ -330,6 +332,7 @@ public class ReceiveCommits {
     this.gerritIdent = gerritIdent;
     this.trackingFooters = trackingFooters;
     this.tagCache = tagCache;
+    this.changeCache = changeCache;
     this.workQueue = workQueue;
     this.changeUpdateExector = changeUpdateExector;
     this.requestScopePropagator = requestScopePropagator;
@@ -352,7 +355,7 @@ public class ReceiveCommits {
 
     if (!projectControl.allRefsAreVisible()) {
       rp.setCheckReferencedObjectsAreReachable(true);
-      rp.setAdvertiseRefsHook(new VisibleRefFilter(tagCache, repo, projectControl, db, false));
+      rp.setAdvertiseRefsHook(new VisibleRefFilter(tagCache, changeCache, repo, projectControl, db, false));
     }
     List<AdvertiseRefsHook> advHooks = new ArrayList<AdvertiseRefsHook>(2);
     advHooks.add(rp.getAdvertiseRefsHook());

gerrit-server/src/main/java/com/google/gerrit/server/git/VisibleRefFilter.java

@@ -22,7 +22,6 @@ import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.project.ProjectControl;
 import com.google.gwtorm.server.OrmException;
-
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.Ref;
 import org.eclipse.jgit.lib.Repository;
@@ -44,16 +43,19 @@ public class VisibleRefFilter extends AbstractAdvertiseRefsHook {
       LoggerFactory.getLogger(VisibleRefFilter.class);
 
   private final TagCache tagCache;
+  private final ChangeCache changeCache;
   private final Repository db;
   private final Project.NameKey projectName;
   private final ProjectControl projectCtl;
   private final ReviewDb reviewDb;
   private final boolean showChanges;
 
-  public VisibleRefFilter(final TagCache tagCache, final Repository db,
+  public VisibleRefFilter(final TagCache tagCache, final ChangeCache changeCache,
+      final Repository db,
       final ProjectControl projectControl, final ReviewDb reviewDb,
       final boolean showChanges) {
     this.tagCache = tagCache;
+    this.changeCache = changeCache;
     this.db = db;
     this.projectName = projectControl.getProject().getNameKey();
     this.projectCtl = projectControl;
@@ -133,7 +135,7 @@ public class VisibleRefFilter extends AbstractAdvertiseRefsHook {
     final Project project = projectCtl.getProject();
     try {
       final Set<Change.Id> visibleChanges = new HashSet<Change.Id>();
-      for (Change change : reviewDb.changes().byProject(project.getNameKey())) {
+      for (Change change : changeCache.get(project.getNameKey())) {
         if (projectCtl.controlFor(change).isVisible(reviewDb)) {
           visibleChanges.add(change.getId());
         }

gerrit-sshd/src/main/java/com/google/gerrit/sshd/commands/Upload.java

@@ -15,6 +15,7 @@
 package com.google.gerrit.sshd.commands;
 
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.git.ChangeCache;
 import com.google.gerrit.server.git.TagCache;
 import com.google.gerrit.server.git.TransferConfig;
 import com.google.gerrit.server.git.VisibleRefFilter;
@@ -37,6 +38,9 @@ final class Upload extends AbstractGitCommand {
   @Inject
   private TagCache tagCache;
 
+  @Inject
+  private ChangeCache changeCache;
+
   @Override
   protected void runImpl() throws IOException, Failure {
     if (!projectControl.canRunUploadPack()) {
@@ -45,7 +49,7 @@ final class Upload extends AbstractGitCommand {
 
     final UploadPack up = new UploadPack(repo);
     if (!projectControl.allRefsAreVisible()) {
-      up.setAdvertiseRefsHook(new VisibleRefFilter(tagCache, repo,
+      up.setAdvertiseRefsHook(new VisibleRefFilter(tagCache, changeCache, repo,
           projectControl, db.get(), true));
     }
     up.setPackConfig(config.getPackConfig());