SONAR-13093 Optimize cache of issues in Compute Engine

20 files changed, 712 insertions, 234 deletions

diff --git a/server/sonar-ce-task-projectanalysis/build.gradle b/server/sonar-ce-task-projectanalysis/build.gradle
index 5cfdd62a4d6..fdef5bf68b5 100644
--- a/server/sonar-ce-task-projectanalysis/build.gradle
+++ b/server/sonar-ce-task-projectanalysis/build.gradle
@@ -43,6 +43,8 @@ dependencies {
 
   compileOnly 'com.google.code.findbugs:jsr305'
 
+  compile project(':server:sonar-db-dao')
+
   testCompile 'com.google.code.findbugs:jsr305'
   testCompile 'com.tngtech.java:junit-dataprovider'
   testCompile 'org.apache.logging.log4j:log4j-api'
@@ -59,4 +61,5 @@ dependencies {
   testFixturesApi testFixtures(project(':server:sonar-ce-task'))
 
   testFixturesCompileOnly 'com.google.code.findbugs:jsr305'
+
 }
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/container/ProjectAnalysisTaskContainerPopulator.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/container/ProjectAnalysisTaskContainerPopulator.java
index ed5b4fd315c..f38405ef195 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/container/ProjectAnalysisTaskContainerPopulator.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/container/ProjectAnalysisTaskContainerPopulator.java
@@ -62,7 +62,7 @@ import org.sonar.ce.task.projectanalysis.issue.DefaultAssignee;
 import org.sonar.ce.task.projectanalysis.issue.EffortAggregator;
 import org.sonar.ce.task.projectanalysis.issue.IntegrateIssuesVisitor;
 import org.sonar.ce.task.projectanalysis.issue.IssueAssigner;
-import org.sonar.ce.task.projectanalysis.issue.IssueCache;
+import org.sonar.ce.task.projectanalysis.issue.ProtoIssueCache;
 import org.sonar.ce.task.projectanalysis.issue.IssueCounter;
 import org.sonar.ce.task.projectanalysis.issue.IssueCreationDateCalculator;
 import org.sonar.ce.task.projectanalysis.issue.IssueLifecycle;
@@ -231,7 +231,7 @@ public final class ProjectAnalysisTaskContainerPopulator implements ContainerPop
       RuleRepositoryImpl.class,
       ScmAccountToUserLoader.class,
       ScmAccountToUser.class,
-      IssueCache.class,
+      ProtoIssueCache.class,
       DefaultAssignee.class,
       IssueVisitors.class,
       IssueLifecycle.class,
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/CloseIssuesOnRemovedComponentsVisitor.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/CloseIssuesOnRemovedComponentsVisitor.java
index e941137ac67..2e4ec262ca8 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/CloseIssuesOnRemovedComponentsVisitor.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/CloseIssuesOnRemovedComponentsVisitor.java
@@ -24,7 +24,7 @@ import java.util.Set;
 import org.sonar.ce.task.projectanalysis.component.Component;
 import org.sonar.ce.task.projectanalysis.component.CrawlerDepthLimit;
 import org.sonar.ce.task.projectanalysis.component.TypeAwareVisitorAdapter;
-import org.sonar.ce.task.projectanalysis.util.cache.DiskCache;
+import org.sonar.ce.task.projectanalysis.util.cache.DiskCache.CacheAppender;
 import org.sonar.core.issue.DefaultIssue;
 
 import static org.sonar.ce.task.projectanalysis.component.ComponentVisitor.Order.POST_ORDER;
@@ -36,15 +36,15 @@ public class CloseIssuesOnRemovedComponentsVisitor extends TypeAwareVisitorAdapt
 
   private final ComponentIssuesLoader issuesLoader;
   private final ComponentsWithUnprocessedIssues componentsWithUnprocessedIssues;
-  private final IssueCache issueCache;
+  private final ProtoIssueCache protoIssueCache;
   private final IssueLifecycle issueLifecycle;
 
-  public CloseIssuesOnRemovedComponentsVisitor(ComponentIssuesLoader issuesLoader, ComponentsWithUnprocessedIssues componentsWithUnprocessedIssues, IssueCache issueCache,
+  public CloseIssuesOnRemovedComponentsVisitor(ComponentIssuesLoader issuesLoader, ComponentsWithUnprocessedIssues componentsWithUnprocessedIssues, ProtoIssueCache protoIssueCache,
     IssueLifecycle issueLifecycle) {
     super(CrawlerDepthLimit.PROJECT, POST_ORDER);
     this.issuesLoader = issuesLoader;
     this.componentsWithUnprocessedIssues = componentsWithUnprocessedIssues;
-    this.issueCache = issueCache;
+    this.protoIssueCache = protoIssueCache;
     this.issueLifecycle = issueLifecycle;
   }
 
@@ -54,7 +54,7 @@ public class CloseIssuesOnRemovedComponentsVisitor extends TypeAwareVisitorAdapt
   }
 
   private void closeIssuesForDeletedComponentUuids(Set<String> deletedComponentUuids) {
-    try (DiskCache<DefaultIssue>.DiskAppender cacheAppender = issueCache.newAppender()) {
+    try (CacheAppender<DefaultIssue> cacheAppender = protoIssueCache.newAppender()) {
       for (String deletedComponentUuid : deletedComponentUuids) {
         List<DefaultIssue> issues = issuesLoader.loadOpenIssues(deletedComponentUuid);
         for (DefaultIssue issue : issues) {
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IntegrateIssuesVisitor.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IntegrateIssuesVisitor.java
index d3c25226230..316f3477db7 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IntegrateIssuesVisitor.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IntegrateIssuesVisitor.java
@@ -26,7 +26,7 @@ import org.sonar.ce.task.projectanalysis.component.Component;
 import org.sonar.ce.task.projectanalysis.component.CrawlerDepthLimit;
 import org.sonar.ce.task.projectanalysis.component.ReferenceBranchComponentUuids;
 import org.sonar.ce.task.projectanalysis.component.TypeAwareVisitorAdapter;
-import org.sonar.ce.task.projectanalysis.util.cache.DiskCache;
+import org.sonar.ce.task.projectanalysis.util.cache.DiskCache.CacheAppender;
 import org.sonar.core.issue.DefaultIssue;
 import org.sonar.core.util.stream.MoreCollectors;
 
@@ -34,17 +34,17 @@ import static org.sonar.ce.task.projectanalysis.component.ComponentVisitor.Order
 
 public class IntegrateIssuesVisitor extends TypeAwareVisitorAdapter {
 
-  private final IssueCache issueCache;
+  private final ProtoIssueCache protoIssueCache;
   private final IssueLifecycle issueLifecycle;
   private final IssueVisitors issueVisitors;
   private final IssueTrackingDelegator issueTracking;
   private final SiblingsIssueMerger issueStatusCopier;
   private final ReferenceBranchComponentUuids referenceBranchComponentUuids;
 
-  public IntegrateIssuesVisitor(IssueCache issueCache, IssueLifecycle issueLifecycle, IssueVisitors issueVisitors, IssueTrackingDelegator issueTracking,
+  public IntegrateIssuesVisitor(ProtoIssueCache protoIssueCache, IssueLifecycle issueLifecycle, IssueVisitors issueVisitors, IssueTrackingDelegator issueTracking,
     SiblingsIssueMerger issueStatusCopier, ReferenceBranchComponentUuids referenceBranchComponentUuids) {
     super(CrawlerDepthLimit.FILE, POST_ORDER);
-    this.issueCache = issueCache;
+    this.protoIssueCache = protoIssueCache;
     this.issueLifecycle = issueLifecycle;
     this.issueVisitors = issueVisitors;
     this.issueTracking = issueTracking;
@@ -54,7 +54,7 @@ public class IntegrateIssuesVisitor extends TypeAwareVisitorAdapter {
 
   @Override
   public void visitAny(Component component) {
-    try (DiskCache<DefaultIssue>.DiskAppender cacheAppender = issueCache.newAppender()) {
+    try (CacheAppender<DefaultIssue> cacheAppender = protoIssueCache.newAppender()) {
       issueVisitors.beforeComponent(component);
       TrackingResult tracking = issueTracking.track(component);
       fillNewOpenIssues(component, tracking.newIssues(), cacheAppender);
@@ -67,7 +67,7 @@ public class IntegrateIssuesVisitor extends TypeAwareVisitorAdapter {
     }
   }
 
-  private void fillNewOpenIssues(Component component, Stream<DefaultIssue> newIssues, DiskCache<DefaultIssue>.DiskAppender cacheAppender) {
+  private void fillNewOpenIssues(Component component, Stream<DefaultIssue> newIssues, CacheAppender<DefaultIssue> cacheAppender) {
     List<DefaultIssue> newIssuesList = newIssues
       .peek(issueLifecycle::initNewOpenIssue)
       .collect(MoreCollectors.toList());
@@ -83,7 +83,7 @@ public class IntegrateIssuesVisitor extends TypeAwareVisitorAdapter {
     }
   }
 
-  private void copyIssues(Component component, Map<DefaultIssue, DefaultIssue> matched, DiskCache<DefaultIssue>.DiskAppender cacheAppender) {
+  private void copyIssues(Component component, Map<DefaultIssue, DefaultIssue> matched, CacheAppender<DefaultIssue> cacheAppender) {
     for (Map.Entry<DefaultIssue, DefaultIssue> entry : matched.entrySet()) {
       DefaultIssue raw = entry.getKey();
       DefaultIssue base = entry.getValue();
@@ -92,7 +92,7 @@ public class IntegrateIssuesVisitor extends TypeAwareVisitorAdapter {
     }
   }
 
-  private void fillExistingOpenIssues(Component component, Map<DefaultIssue, DefaultIssue> matched, DiskCache<DefaultIssue>.DiskAppender cacheAppender) {
+  private void fillExistingOpenIssues(Component component, Map<DefaultIssue, DefaultIssue> matched, CacheAppender<DefaultIssue> cacheAppender) {
     for (Map.Entry<DefaultIssue, DefaultIssue> entry : matched.entrySet()) {
       DefaultIssue raw = entry.getKey();
       DefaultIssue base = entry.getValue();
@@ -101,7 +101,7 @@ public class IntegrateIssuesVisitor extends TypeAwareVisitorAdapter {
     }
   }
 
-  private void closeIssues(Component component, Stream<DefaultIssue> issues, DiskCache<DefaultIssue>.DiskAppender cacheAppender) {
+  private void closeIssues(Component component, Stream<DefaultIssue> issues, CacheAppender<DefaultIssue> cacheAppender) {
     issues.forEach(issue -> {
       // TODO should replace flag "beingClosed" by express call to transition "automaticClose"
       issue.setBeingClosed(true);
@@ -110,10 +110,12 @@ public class IntegrateIssuesVisitor extends TypeAwareVisitorAdapter {
     });
   }
 
-  private void process(Component component, DefaultIssue issue, DiskCache<DefaultIssue>.DiskAppender cacheAppender) {
+  private void process(Component component, DefaultIssue issue, CacheAppender<DefaultIssue> cacheAppender) {
     issueLifecycle.doAutomaticTransition(issue);
     issueVisitors.onIssue(component, issue);
-    cacheAppender.append(issue);
+    if (issue.isNew() || issue.isChanged() || issue.isCopied()) {
+      cacheAppender.append(issue);
+    }
   }
 
 }
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IssueLifecycle.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IssueLifecycle.java
index 72526f97d2e..7fe33850709 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IssueLifecycle.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IssueLifecycle.java
@@ -147,7 +147,8 @@ public class IssueLifecycle {
     result.setUserUuid(c.userUuid());
     result.setCreationDate(c.creationDate());
     // Don't copy "file" changelogs as they refer to file uuids that might later be purged
-    c.diffs().entrySet().stream().filter(e -> !e.getKey().equals(IssueFieldsSetter.FILE))
+    c.diffs().entrySet().stream()
+      .filter(e -> !e.getKey().equals(IssueFieldsSetter.FILE))
       .forEach(e -> result.setDiff(e.getKey(), e.getValue().oldValue(), e.getValue().newValue()));
     if (result.diffs().isEmpty()) {
       return Optional.empty();
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IssueCache.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/ProtoIssueCache.java
index dafcb1561fd..bf1ee1ef29a 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/IssueCache.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/issue/ProtoIssueCache.java
@@ -22,21 +22,20 @@ package org.sonar.ce.task.projectanalysis.issue;
 import java.io.File;
 import org.sonar.api.utils.System2;
 import org.sonar.api.utils.TempFolder;
-import org.sonar.ce.task.projectanalysis.util.cache.DiskCache;
-import org.sonar.core.issue.DefaultIssue;
+import org.sonar.ce.task.projectanalysis.util.cache.ProtobufIssueDiskCache;
 
 /**
  * Cache of all the issues involved in the analysis. Their state is as it will be
  * persisted in database (after issue tracking, auto-assignment, ...)
  */
-public class IssueCache extends DiskCache<DefaultIssue> {
+public class ProtoIssueCache extends ProtobufIssueDiskCache {
 
   // this constructor is used by picocontainer
-  public IssueCache(TempFolder tempFolder, System2 system2) {
+  public ProtoIssueCache(TempFolder tempFolder, System2 system2) {
     super(tempFolder.newFile("issues", ".dat"), system2);
   }
 
-  public IssueCache(File file, System2 system2) {
+  public ProtoIssueCache(File file, System2 system2) {
     super(file, system2);
   }
 }
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/PersistIssuesStep.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/PersistIssuesStep.java
index d7a61ff8840..d4db74ea7da 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/PersistIssuesStep.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/PersistIssuesStep.java
@@ -22,8 +22,9 @@ package org.sonar.ce.task.projectanalysis.step;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.Map;
+import org.apache.commons.io.FileUtils;
 import org.sonar.api.utils.System2;
-import org.sonar.ce.task.projectanalysis.issue.IssueCache;
+import org.sonar.ce.task.projectanalysis.issue.ProtoIssueCache;
 import org.sonar.ce.task.projectanalysis.issue.RuleRepository;
 import org.sonar.ce.task.projectanalysis.issue.UpdateConflictResolver;
 import org.sonar.ce.task.step.ComputationStep;
@@ -49,24 +50,26 @@ public class PersistIssuesStep implements ComputationStep {
   private final System2 system2;
   private final UpdateConflictResolver conflictResolver;
   private final RuleRepository ruleRepository;
-  private final IssueCache issueCache;
+  private final ProtoIssueCache protoIssueCache;
   private final IssueStorage issueStorage;
 
   public PersistIssuesStep(DbClient dbClient, System2 system2, UpdateConflictResolver conflictResolver,
-    RuleRepository ruleRepository, IssueCache issueCache, IssueStorage issueStorage) {
+    RuleRepository ruleRepository, ProtoIssueCache protoIssueCache, IssueStorage issueStorage) {
     this.dbClient = dbClient;
     this.system2 = system2;
     this.conflictResolver = conflictResolver;
     this.ruleRepository = ruleRepository;
-    this.issueCache = issueCache;
+    this.protoIssueCache = protoIssueCache;
     this.issueStorage = issueStorage;
   }
 
   @Override
   public void execute(ComputationStep.Context context) {
+    context.getStatistics().add("cacheSize", FileUtils.byteCountToDisplaySize(protoIssueCache.fileSize()));
     IssueStatistics statistics = new IssueStatistics();
     try (DbSession dbSession = dbClient.openSession(true);
-      CloseableIterator<DefaultIssue> issues = issueCache.traverse()) {
+
+      CloseableIterator<DefaultIssue> issues = protoIssueCache.traverse()) {
       List<DefaultIssue> addedIssues = new ArrayList<>(ISSUE_BATCHING_SIZE);
       List<DefaultIssue> updatedIssues = new ArrayList<>(ISSUE_BATCHING_SIZE);
 
@@ -86,8 +89,6 @@ public class PersistIssuesStep implements ComputationStep {
             persistUpdatedIssues(statistics, updatedIssues, mapper, changeMapper);
             updatedIssues.clear();
           }
-        } else {
-          statistics.untouched++;
         }
       }
       persistNewIssues(statistics, addedIssues, mapper, changeMapper);
@@ -156,14 +157,12 @@ public class PersistIssuesStep implements ComputationStep {
     private int inserts = 0;
     private int updates = 0;
     private int merged = 0;
-    private int untouched = 0;
 
     private void dumpTo(ComputationStep.Context context) {
       context.getStatistics()
         .add("inserts", String.valueOf(inserts))
         .add("updates", String.valueOf(updates))
-        .add("merged", String.valueOf(merged))
-        .add("untouched", String.valueOf(untouched));
+        .add("merged", String.valueOf(merged));
     }
   }
 }
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/SendIssueNotificationsStep.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/SendIssueNotificationsStep.java
index 72fd08f6c2d..46d91525b7a 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/SendIssueNotificationsStep.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/step/SendIssueNotificationsStep.java
@@ -39,7 +39,7 @@ import org.sonar.ce.task.projectanalysis.analysis.AnalysisMetadataHolder;
 import org.sonar.ce.task.projectanalysis.analysis.Branch;
 import org.sonar.ce.task.projectanalysis.component.Component;
 import org.sonar.ce.task.projectanalysis.component.TreeRootHolder;
-import org.sonar.ce.task.projectanalysis.issue.IssueCache;
+import org.sonar.ce.task.projectanalysis.issue.ProtoIssueCache;
 import org.sonar.ce.task.projectanalysis.notification.NotificationFactory;
 import org.sonar.ce.task.step.ComputationStep;
 import org.sonar.core.issue.DefaultIssue;
@@ -72,17 +72,17 @@ public class SendIssueNotificationsStep implements ComputationStep {
    */
   static final Set<Class<? extends Notification>> NOTIF_TYPES = ImmutableSet.of(NewIssuesNotification.class, MyNewIssuesNotification.class, IssuesChangesNotification.class);
 
-  private final IssueCache issueCache;
+  private final ProtoIssueCache protoIssueCache;
   private final TreeRootHolder treeRootHolder;
   private final NotificationService service;
   private final AnalysisMetadataHolder analysisMetadataHolder;
   private final NotificationFactory notificationFactory;
   private final DbClient dbClient;
 
-  public SendIssueNotificationsStep(IssueCache issueCache, TreeRootHolder treeRootHolder,
+  public SendIssueNotificationsStep(ProtoIssueCache protoIssueCache, TreeRootHolder treeRootHolder,
     NotificationService service, AnalysisMetadataHolder analysisMetadataHolder,
     NotificationFactory notificationFactory, DbClient dbClient) {
-    this.issueCache = issueCache;
+    this.protoIssueCache = protoIssueCache;
     this.treeRootHolder = treeRootHolder;
     this.service = service;
     this.analysisMetadataHolder = analysisMetadataHolder;
@@ -111,12 +111,12 @@ public class SendIssueNotificationsStep implements ComputationStep {
     NewIssuesStatistics newIssuesStats = new NewIssuesStatistics(onCurrentAnalysis);
     Map<String, UserDto> assigneesByUuid;
     try (DbSession dbSession = dbClient.openSession(false)) {
-      Iterable<DefaultIssue> iterable = issueCache::traverse;
+      Iterable<DefaultIssue> iterable = protoIssueCache::traverse;
       Set<String> assigneeUuids = stream(iterable.spliterator(), false).map(DefaultIssue::assignee).filter(Objects::nonNull).collect(Collectors.toSet());
       assigneesByUuid = dbClient.userDao().selectByUuids(dbSession, assigneeUuids).stream().collect(toMap(UserDto::getUuid, dto -> dto));
     }
 
-    try (CloseableIterator<DefaultIssue> issues = issueCache.traverse()) {
+    try (CloseableIterator<DefaultIssue> issues = protoIssueCache.traverse()) {
       processIssues(newIssuesStats, issues, assigneesByUuid, notificationStatistics);
     }
     if (newIssuesStats.hasIssuesOnCurrentAnalysis()) {
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/DiskCache.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/DiskCache.java
index 81fa28b2548..d278ce84637 100644
--- a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/DiskCache.java
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/DiskCache.java
@@ -19,90 +19,20 @@
  */
 package org.sonar.ce.task.projectanalysis.util.cache;
 
-import java.io.File;
-import java.io.FileOutputStream;
-import java.io.IOException;
-import java.io.ObjectOutputStream;
-import java.io.OutputStream;
 import java.io.Serializable;
-import org.apache.commons.io.FileUtils;
-import org.apache.commons.io.IOUtils;
-import org.sonar.api.utils.System2;
 import org.sonar.core.util.CloseableIterator;
 
-/**
- * Serialize and deserialize objects on disk. No search capabilities, only traversal (full scan).
- */
-public class DiskCache<O extends Serializable> {
-
-  private final File file;
-  private final System2 system2;
-
-  public DiskCache(File file, System2 system2) {
-    this.system2 = system2;
-    this.file = file;
-    OutputStream output = null;
-    boolean threw = true;
-    try {
-      // writes the serialization stream header required when calling "traverse()"
-      // on empty stream. Moreover it allows to call multiple times "newAppender()"
-      output = new ObjectOutputStream(new FileOutputStream(file));
-      output.flush();
-      threw = false;
-    } catch (IOException e) {
-      throw new IllegalStateException("Fail to write into file: " + file, e);
-    } finally {
-      if (threw) {
-        // do not hide initial exception
-        IOUtils.closeQuietly(output);
-      } else {
-        // raise an exception if can't close
-        system2.close(output);
-      }
-    }
-  }
-
-  public DiskAppender newAppender() {
-    return new DiskAppender();
-  }
-
-  public CloseableIterator<O> traverse() {
-    try {
-      return new ObjectInputStreamIterator<>(FileUtils.openInputStream(file));
-    } catch (IOException e) {
-      throw new IllegalStateException("Fail to traverse file: " + file, e);
-    }
-  }
+public interface DiskCache<O extends Serializable> {
+  long fileSize();
 
-  public class DiskAppender implements AutoCloseable {
-    private final ObjectOutputStream output;
+  CacheAppender<O> newAppender();
 
-    private DiskAppender() {
-      try {
-        this.output = new ObjectOutputStream(new FileOutputStream(file, true)) {
-          @Override
-          protected void writeStreamHeader() {
-            // do not write stream headers as it's already done in constructor of DiskCache
-          }
-        };
-      } catch (IOException e) {
-        throw new IllegalStateException("Fail to open file " + file, e);
-      }
-    }
+  CloseableIterator<O> traverse();
 
-    public DiskAppender append(O object) {
-      try {
-        output.writeObject(object);
-        output.reset();
-        return this;
-      } catch (IOException e) {
-        throw new IllegalStateException("Fail to write into file " + file, e);
-      }
-    }
+  interface CacheAppender<I extends Serializable> extends AutoCloseable {
+    CacheAppender<I> append(I object);
 
     @Override
-    public void close() {
-      system2.close(output);
-    }
+    void close();
   }
 }
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/JavaSerializationDiskCache.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/JavaSerializationDiskCache.java
new file mode 100644
index 00000000000..40e50783973
--- /dev/null
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/JavaSerializationDiskCache.java
@@ -0,0 +1,116 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2020 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.ce.task.projectanalysis.util.cache;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.ObjectOutputStream;
+import java.io.OutputStream;
+import java.io.Serializable;
+import org.apache.commons.io.FileUtils;
+import org.apache.commons.io.IOUtils;
+import org.sonar.api.utils.System2;
+import org.sonar.core.util.CloseableIterator;
+
+/**
+ * Serialize and deserialize objects on disk. No search capabilities, only traversal (full scan).
+ */
+public class JavaSerializationDiskCache<O extends Serializable> implements DiskCache<O> {
+
+  private final File file;
+  private final System2 system2;
+
+  public JavaSerializationDiskCache(File file, System2 system2) {
+    this.system2 = system2;
+    this.file = file;
+    OutputStream output = null;
+    boolean threw = true;
+    try {
+      // writes the serialization stream header required when calling "traverse()"
+      // on empty stream. Moreover it allows to call multiple times "newAppender()"
+      output = new ObjectOutputStream(new FileOutputStream(file));
+      output.flush();
+      threw = false;
+    } catch (IOException e) {
+      throw new IllegalStateException("Fail to write into file: " + file, e);
+    } finally {
+      if (threw) {
+        // do not hide initial exception
+        IOUtils.closeQuietly(output);
+      } else {
+        // raise an exception if can't close
+        system2.close(output);
+      }
+    }
+  }
+
+  @Override
+  public long fileSize() {
+    return file.length();
+  }
+
+  @Override
+  public CacheAppender<O> newAppender() {
+    return new JavaSerializationCacheAppender();
+  }
+
+  @Override
+  public CloseableIterator<O> traverse() {
+    try {
+      return new ObjectInputStreamIterator<>(FileUtils.openInputStream(file));
+    } catch (IOException e) {
+      throw new IllegalStateException("Fail to traverse file: " + file, e);
+    }
+  }
+
+  public class JavaSerializationCacheAppender<O extends Serializable> implements CacheAppender<O> {
+    private final ObjectOutputStream output;
+
+    private JavaSerializationCacheAppender() {
+      try {
+        this.output = new ObjectOutputStream(new FileOutputStream(file, true)) {
+          @Override
+          protected void writeStreamHeader() {
+            // do not write stream headers as it's already done in constructor of DiskCache
+          }
+        };
+      } catch (IOException e) {
+        throw new IllegalStateException("Fail to open file " + file, e);
+      }
+    }
+
+    @Override
+    public CacheAppender append(O object) {
+      try {
+        output.writeObject(object);
+        output.reset();
+        return this;
+      } catch (IOException e) {
+        throw new IllegalStateException("Fail to write into file " + file, e);
+      }
+    }
+
+    @Override
+    public void close() {
+      system2.close(output);
+    }
+  }
+}
diff --git a/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/ProtobufIssueDiskCache.java b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/ProtobufIssueDiskCache.java
new file mode 100644
index 00000000000..3dc527a31ad
--- /dev/null
+++ b/server/sonar-ce-task-projectanalysis/src/main/java/org/sonar/ce/task/projectanalysis/util/cache/ProtobufIssueDiskCache.java
@@ -0,0 +1,283 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2020 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.ce.task.projectanalysis.util.cache;
+
+import com.google.common.base.Joiner;
+import com.google.common.base.Splitter;
+import com.google.common.collect.ImmutableSet;
+import java.io.BufferedOutputStream;
+import java.io.File;
+import java.io.FileNotFoundException;
+import java.io.FileOutputStream;
+import java.io.OutputStream;
+import java.util.Collections;
+import java.util.Date;
+import java.util.Map;
+import javax.annotation.CheckForNull;
+import org.sonar.api.rule.RuleKey;
+import org.sonar.api.rules.RuleType;
+import org.sonar.api.utils.Duration;
+import org.sonar.api.utils.System2;
+import org.sonar.core.issue.DefaultIssue;
+import org.sonar.core.issue.DefaultIssueComment;
+import org.sonar.core.issue.FieldDiffs;
+import org.sonar.core.util.CloseableIterator;
+import org.sonar.core.util.Protobuf;
+import org.sonar.db.protobuf.DbIssues;
+
+import static java.util.Optional.ofNullable;
+
+public class ProtobufIssueDiskCache implements DiskCache<DefaultIssue> {
+  private static final String TAGS_SEPARATOR = ",";
+  private static final Splitter TAGS_SPLITTER = Splitter.on(',').trimResults().omitEmptyStrings();
+
+  private final File file;
+  private final System2 system2;
+
+  public ProtobufIssueDiskCache(File file, System2 system2) {
+    this.file = file;
+    this.system2 = system2;
+  }
+
+  @Override
+  public long fileSize() {
+    return file.length();
+  }
+
+  @Override
+  public CacheAppender<DefaultIssue> newAppender() {
+    try {
+      return new ProtoCacheAppender();
+    } catch (FileNotFoundException e) {
+      throw new IllegalStateException(e);
+    }
+  }
+
+  @Override
+  public CloseableIterator<DefaultIssue> traverse() {
+    CloseableIterator<IssueCache.Issue> protoIterator = Protobuf.readStream(file, IssueCache.Issue.parser());
+    return new CloseableIterator<DefaultIssue>() {
+      @CheckForNull
+      @Override
+      protected DefaultIssue doNext() {
+        if (protoIterator.hasNext()) {
+          return toDefaultIssue(protoIterator.next());
+        }
+        return null;
+      }
+
+      @Override
+      protected void doClose() {
+        protoIterator.close();
+      }
+    };
+  }
+
+  private static DefaultIssue toDefaultIssue(IssueCache.Issue next) {
+    DefaultIssue defaultIssue = new DefaultIssue();
+    defaultIssue.setKey(next.getKey());
+    defaultIssue.setType(RuleType.valueOf(next.getRuleType()));
+    defaultIssue.setComponentUuid(next.hasComponentUuid() ? next.getComponentUuid() : null);
+    defaultIssue.setComponentKey(next.getComponentKey());
+    defaultIssue.setModuleUuid(next.hasModuleUuid() ? next.getModuleUuid() : null);
+    defaultIssue.setModuleUuidPath(next.hasModuleUuidPath() ? next.getModuleUuidPath() : null);
+    defaultIssue.setProjectUuid(next.getProjectUuid());
+    defaultIssue.setProjectKey(next.getProjectKey());
+    defaultIssue.setRuleKey(RuleKey.parse(next.getRuleKey()));
+    defaultIssue.setLanguage(next.hasLanguage() ? next.getLanguage() : null);
+    defaultIssue.setSeverity(next.hasSeverity() ? next.getSeverity() : null);
+    defaultIssue.setManualSeverity(next.getManualSeverity());
+    defaultIssue.setMessage(next.hasMessage() ? next.getMessage() : null);
+    defaultIssue.setLine(next.hasLine() ? next.getLine() : null);
+    defaultIssue.setGap(next.hasGap() ? next.getGap() : null);
+    defaultIssue.setEffort(next.hasEffort() ? Duration.create(next.getEffort()) : null);
+    defaultIssue.setStatus(next.getStatus());
+    defaultIssue.setResolution(next.hasResolution() ? next.getResolution() : null);
+    defaultIssue.setAssigneeUuid(next.hasAssigneeUuid() ? next.getAssigneeUuid() : null);
+    defaultIssue.setChecksum(next.hasChecksum() ? next.getChecksum() : null);
+    defaultIssue.setAttributes(next.getAttributesMap());
+    defaultIssue.setAuthorLogin(next.hasAuthorLogin() ? next.getAuthorLogin() : null);
+    next.getCommentsList().forEach(c -> defaultIssue.addComment(toDefaultIssueComment(c)));
+    defaultIssue.setTags(ImmutableSet.copyOf(TAGS_SPLITTER.split(next.hasTags() ? "" : next.getTags())));
+    defaultIssue.setLocations(next.hasLocations() ? next.getLocations() : null);
+    defaultIssue.setIsFromExternalRuleEngine(next.getIsFromExternalRuleEngine());
+    defaultIssue.setCreationDate(new Date(next.getCreationDate()));
+    defaultIssue.setUpdateDate(next.hasUpdateDate() ? new Date(next.getUpdateDate()) : null);
+    defaultIssue.setCloseDate(next.hasCloseDate() ? new Date(next.getCloseDate()) : null);
+    defaultIssue.setCurrentChangeWithoutAddChange(next.hasCurrentChanges() ? toDefaultIssueChanges(next.getCurrentChanges()) : null);
+    defaultIssue.setNew(next.getIsNew());
+    defaultIssue.setCopied(next.getIsCopied());
+    defaultIssue.setBeingClosed(next.getBeingClosed());
+    defaultIssue.setOnDisabledRule(next.getOnDisabledRule());
+    defaultIssue.setChanged(next.getIsChanged());
+    defaultIssue.setSendNotifications(next.getSendNotifications());
+    defaultIssue.setSelectedAt(next.hasSelectedAt() ? next.getSelectedAt() : null);
+
+    for (IssueCache.FieldDiffs protoFieldDiffs : next.getChangesList()) {
+      defaultIssue.addChange(toDefaultIssueChanges(protoFieldDiffs));
+    }
+
+    return defaultIssue;
+  }
+
+  private static IssueCache.Issue toProto(IssueCache.Issue.Builder builder, DefaultIssue defaultIssue) {
+    builder.clear();
+    builder.setKey(defaultIssue.key());
+    builder.setRuleType(defaultIssue.type().getDbConstant());
+    ofNullable(defaultIssue.componentUuid()).ifPresent(builder::setComponentUuid);
+    builder.setComponentKey(defaultIssue.componentKey());
+    ofNullable(defaultIssue.moduleUuid()).ifPresent(builder::setModuleUuid);
+    ofNullable(defaultIssue.moduleUuidPath()).ifPresent(builder::setModuleUuidPath);
+    builder.setProjectUuid(defaultIssue.projectUuid());
+    builder.setProjectKey(defaultIssue.projectKey());
+    builder.setRuleKey(defaultIssue.ruleKey().toString());
+    ofNullable(defaultIssue.language()).ifPresent(builder::setLanguage);
+    ofNullable(defaultIssue.severity()).ifPresent(builder::setSeverity);
+    builder.setManualSeverity(defaultIssue.manualSeverity());
+    ofNullable(defaultIssue.message()).ifPresent(builder::setMessage);
+    ofNullable(defaultIssue.line()).ifPresent(builder::setLine);
+    ofNullable(defaultIssue.gap()).ifPresent(builder::setGap);
+    ofNullable(defaultIssue.effort()).map(Duration::toMinutes).ifPresent(builder::setEffort);
+    builder.setStatus(defaultIssue.status());
+    ofNullable(defaultIssue.resolution()).ifPresent(builder::setResolution);
+    ofNullable(defaultIssue.assignee()).ifPresent(builder::setAssigneeUuid);
+    ofNullable(defaultIssue.checksum()).ifPresent(builder::setChecksum);
+    ofNullable(defaultIssue.attributes()).ifPresent(builder::putAllAttributes);
+    ofNullable(defaultIssue.authorLogin()).ifPresent(builder::setAuthorLogin);
+    defaultIssue.defaultIssueComments().forEach(c -> builder.addComments(toProtoComment(c)));
+    ofNullable(defaultIssue.tags()).ifPresent(t -> builder.setTags(String.join(TAGS_SEPARATOR, t)));
+    ofNullable(defaultIssue.getLocations()).ifPresent(l -> builder.setLocations((DbIssues.Locations) l));
+    builder.setIsFromExternalRuleEngine(defaultIssue.isFromExternalRuleEngine());
+    builder.setCreationDate(defaultIssue.creationDate().getTime());
+    ofNullable(defaultIssue.updateDate()).map(Date::getTime).ifPresent(builder::setUpdateDate);
+    ofNullable(defaultIssue.closeDate()).map(Date::getTime).ifPresent(builder::setCloseDate);
+    ofNullable(defaultIssue.currentChange()).ifPresent(c -> builder.setCurrentChanges(toProtoIssueChanges(c)));
+    builder.setIsNew(defaultIssue.isNew());
+    builder.setIsCopied(defaultIssue.isCopied());
+    builder.setBeingClosed(defaultIssue.isBeingClosed());
+    builder.setOnDisabledRule(defaultIssue.isOnDisabledRule());
+    builder.setIsChanged(defaultIssue.isChanged());
+    builder.setSendNotifications(defaultIssue.mustSendNotifications());
+    ofNullable(defaultIssue.selectedAt()).ifPresent(builder::setSelectedAt);
+
+    for (FieldDiffs fieldDiffs : defaultIssue.changes()) {
+      builder.addChanges(toProtoIssueChanges(fieldDiffs));
+    }
+
+    return builder.build();
+  }
+
+  private static DefaultIssueComment toDefaultIssueComment(IssueCache.Comment comment) {
+    DefaultIssueComment issueComment = new DefaultIssueComment()
+      .setCreatedAt(new Date(comment.getCreatedAt()))
+      .setUpdatedAt(new Date(comment.getUpdatedAt()))
+      .setNew(comment.getIsNew())
+      .setKey(comment.getKey())
+      .setIssueKey(comment.getIssueKey())
+      .setMarkdownText(comment.getMarkdownText());
+
+    if (comment.hasUserUuid()) {
+      issueComment.setUserUuid(comment.getUserUuid());
+    }
+    return issueComment;
+  }
+
+  private static IssueCache.Comment toProtoComment(DefaultIssueComment comment) {
+    IssueCache.Comment.Builder builder = IssueCache.Comment.newBuilder()
+      .setCreatedAt(comment.createdAt().getTime())
+      .setUpdatedAt(comment.updatedAt().getTime())
+      .setIsNew(comment.isNew())
+      .setKey(comment.key())
+      .setIssueKey(comment.issueKey())
+      .setMarkdownText(comment.markdownText());
+
+    if (comment.userUuid() != null) {
+      builder.setUserUuid(comment.userUuid());
+    }
+    return builder.build();
+  }
+
+  private static FieldDiffs toDefaultIssueChanges(IssueCache.FieldDiffs fieldDiffs) {
+    FieldDiffs defaultIssueFieldDiffs = new FieldDiffs()
+      .setUserUuid(fieldDiffs.getUserUuid())
+      .setCreationDate(new Date(fieldDiffs.getCreationDate()));
+
+    if (fieldDiffs.hasIssueKey()) {
+      defaultIssueFieldDiffs.setIssueKey(fieldDiffs.getIssueKey());
+    }
+
+    for (Map.Entry<String, IssueCache.Diff> e : fieldDiffs.getDiffsMap().entrySet()) {
+      defaultIssueFieldDiffs.setDiff(e.getKey(),
+        e.getValue().hasOldValue() ? e.getValue().getOldValue() : null,
+        e.getValue().hasNewValue() ? e.getValue().getNewValue() : null);
+    }
+
+    return defaultIssueFieldDiffs;
+  }
+
+  private static IssueCache.FieldDiffs toProtoIssueChanges(FieldDiffs fieldDiffs) {
+    IssueCache.FieldDiffs.Builder builder = IssueCache.FieldDiffs.newBuilder()
+      .setCreationDate(fieldDiffs.creationDate().getTime());
+
+    if (fieldDiffs.issueKey() != null) {
+      builder.setIssueKey(fieldDiffs.issueKey());
+    }
+
+    String userUuid = fieldDiffs.userUuid();
+    if (userUuid != null) {
+      builder.setUserUuid(userUuid);
+    }
+
+    for (Map.Entry<String, FieldDiffs.Diff> e : fieldDiffs.diffs().entrySet()) {
+      IssueCache.Diff.Builder diffBuilder = IssueCache.Diff.newBuilder();
+      if (e.getValue().oldValue() != null) {
+        diffBuilder.setOldValue(e.getValue().oldValue().toString());
+      }
+      if (e.getValue().newValue() != null) {
+        diffBuilder.setNewValue(e.getValue().newValue().toString());
+
+      }
+      builder.putDiffs(e.getKey(), diffBuilder.build());
+    }
+
+    return builder.build();
+  }
+
+  private class ProtoCacheAppender implements CacheAppender<DefaultIssue> {
+    private final OutputStream out;
+    private final IssueCache.Issue.Builder builder;
+
+    private ProtoCacheAppender() throws FileNotFoundException {
+      this.out = new BufferedOutputStream(new FileOutputStream(file, true));
+      this.builder = IssueCache.Issue.newBuilder();
+    }
+
+    @Override
+    public CacheAppender append(DefaultIssue object) {
+      Protobuf.writeStream(Collections.singleton(toProto(builder, object)), out);
+      return this;
+    }
+
+    @Override
+    public void close() {
+      system2.close(out);
+    }
+  }
+}
diff --git a/server/sonar-ce-task-projectanalysis/src/main/protobuf/issue_cache.proto b/server/sonar-ce-task-projectanalysis/src/main/protobuf/issue_cache.proto
new file mode 100644
index 00000000000..bb3352920a5
--- /dev/null
+++ b/server/sonar-ce-task-projectanalysis/src/main/protobuf/issue_cache.proto
@@ -0,0 +1,98 @@
+// SonarQube, open source software quality management tool.
+// Copyright (C) 2008-2016 SonarSource
+// mailto:contact AT sonarsource DOT com
+//
+// SonarQube is free software; you can redistribute it and/or
+// modify it under the terms of the GNU Lesser General Public
+// License as published by the Free Software Foundation; either
+// version 3 of the License, or (at your option) any later version.
+//
+// SonarQube is distributed in the hope that it will be useful,
+// but WITHOUT ANY WARRANTY; without even the implied warranty of
+// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+// Lesser General Public License for more details.
+//
+// You should have received a copy of the GNU Lesser General Public License
+// along with this program; if not, write to the Free Software Foundation,
+// Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+
+
+// IMPORTANT
+// This is beta version of specification. It will evolve during next
+// releases and is not forward-compatible yet.
+
+syntax = "proto2";
+
+import "db-issues.proto";
+
+option java_package = "org.sonar.ce.task.projectanalysis.util.cache";
+option optimize_for = SPEED;
+
+message Issue {
+  optional string key = 1;
+  optional int32 ruleType = 2;
+  optional string componentUuid = 3;
+  optional string componentKey = 4;
+  optional string moduleUuid = 5;
+  optional string moduleUuidPath = 6;
+  optional string projectUuid = 7;
+  optional string projectKey = 8;
+  optional string ruleKey = 9;
+  optional string language = 10;
+  optional string severity = 11;
+  optional bool manualSeverity = 12;
+  optional string message = 13;
+  optional int32 line = 14;
+  optional double gap = 15;
+  optional int64 effort = 16;
+  optional string status = 17;
+  optional string resolution = 18;
+  optional string assigneeUuid = 19;
+  optional string checksum = 20;
+  map<string, string> attributes = 21;
+  optional string authorLogin = 22;
+  optional string tags = 23;
+  optional sonarqube.db.issues.Locations locations = 24;
+
+  optional bool isFromExternalRuleEngine = 25;
+
+   // FUNCTIONAL DATES
+  optional int64 creationDate = 26;
+  optional int64 updateDate = 27;
+  optional int64 closeDate = 28;
+
+  repeated FieldDiffs changes = 29;
+  optional FieldDiffs currentChanges = 30;
+
+  optional bool isNew = 31;
+  optional bool isCopied = 32;
+  optional bool beingClosed = 33;
+  optional bool onDisabledRule = 34;
+  optional bool isChanged = 35;
+  optional bool sendNotifications = 36;
+  optional int64 selectedAt = 37;
+
+  repeated Comment comments = 38;
+}
+
+message Comment {
+  optional string issueKey = 1;
+  optional string userUuid = 2;
+  optional int64 createdAt = 3;
+  optional int64 updatedAt = 4;
+  optional string key = 5;
+  optional string markdownText = 6;
+  optional bool isNew = 7;
+}
+
+message FieldDiffs {
+  optional string userUuid = 1;
+  optional int64 creationDate = 2;
+  optional string issueKey = 3;
+  map<string, Diff> diffs = 4;
+}
+
+message Diff {
+  optional string oldValue = 1;
+  optional string newValue = 2;
+}
diff --git a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/issue/CloseIssuesOnRemovedComponentsVisitorTest.java b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/issue/CloseIssuesOnRemovedComponentsVisitorTest.java
index 1ee09d31c0b..abce9e939e8 100644
--- a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/issue/CloseIssuesOnRemovedComponentsVisitorTest.java
+++ b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/issue/CloseIssuesOnRemovedComponentsVisitorTest.java
@@ -21,10 +21,13 @@ package org.sonar.ce.task.projectanalysis.issue;
 
 import java.util.Arrays;
 import java.util.Collections;
+import java.util.Date;
 import org.junit.Before;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
+import org.sonar.api.rule.RuleKey;
+import org.sonar.api.rules.RuleType;
 import org.sonar.api.utils.System2;
 import org.sonar.ce.task.projectanalysis.component.ReportComponent;
 import org.sonar.ce.task.projectanalysis.component.VisitorsCrawler;
@@ -49,14 +52,14 @@ public class CloseIssuesOnRemovedComponentsVisitorTest {
   ComponentIssuesLoader issuesLoader = mock(ComponentIssuesLoader.class);
   ComponentsWithUnprocessedIssues componentsWithUnprocessedIssues = mock(ComponentsWithUnprocessedIssues.class);
   IssueLifecycle issueLifecycle = mock(IssueLifecycle.class);
-  IssueCache issueCache;
+  ProtoIssueCache protoIssueCache;
   VisitorsCrawler underTest;
 
   @Before
   public void setUp() throws Exception {
-    issueCache = new IssueCache(temp.newFile(), System2.INSTANCE);
+    protoIssueCache = new ProtoIssueCache(temp.newFile(), System2.INSTANCE);
     underTest = new VisitorsCrawler(
-      Arrays.asList(new CloseIssuesOnRemovedComponentsVisitor(issuesLoader, componentsWithUnprocessedIssues, issueCache, issueLifecycle)));
+      Arrays.asList(new CloseIssuesOnRemovedComponentsVisitor(issuesLoader, componentsWithUnprocessedIssues, protoIssueCache, issueLifecycle)));
   }
 
   @Test
@@ -65,13 +68,14 @@ public class CloseIssuesOnRemovedComponentsVisitorTest {
     String issueUuid = "ABCD";
 
     when(componentsWithUnprocessedIssues.getUuids()).thenReturn(newHashSet(fileUuid));
-    DefaultIssue issue = new DefaultIssue().setKey(issueUuid);
+    DefaultIssue issue = new DefaultIssue().setKey(issueUuid).setType(RuleType.BUG).setCreationDate(new Date())
+      .setComponentKey("c").setProjectUuid("u").setProjectKey("k").setRuleKey(RuleKey.of("r", "r")).setStatus("OPEN");
     when(issuesLoader.loadOpenIssues(fileUuid)).thenReturn(Collections.singletonList(issue));
 
     underTest.visit(ReportComponent.builder(PROJECT, 1).build());
 
     verify(issueLifecycle).doAutomaticTransition(issue);
-    CloseableIterator<DefaultIssue> issues = issueCache.traverse();
+    CloseableIterator<DefaultIssue> issues = protoIssueCache.traverse();
     assertThat(issues.hasNext()).isTrue();
 
     DefaultIssue result = issues.next();
@@ -87,7 +91,7 @@ public class CloseIssuesOnRemovedComponentsVisitorTest {
     underTest.visit(ReportComponent.builder(PROJECT, 1).build());
 
     verifyZeroInteractions(issueLifecycle);
-    CloseableIterator<DefaultIssue> issues = issueCache.traverse();
+    CloseableIterator<DefaultIssue> issues = protoIssueCache.traverse();
     assertThat(issues.hasNext()).isFalse();
   }
 
@@ -96,7 +100,7 @@ public class CloseIssuesOnRemovedComponentsVisitorTest {
     underTest.visit(ReportComponent.builder(DIRECTORY, 1).build());
 
     verifyZeroInteractions(issueLifecycle);
-    CloseableIterator<DefaultIssue> issues = issueCache.traverse();
+    CloseableIterator<DefaultIssue> issues = protoIssueCache.traverse();
     assertThat(issues.hasNext()).isFalse();
   }
 
@@ -105,7 +109,7 @@ public class CloseIssuesOnRemovedComponentsVisitorTest {
     underTest.visit(ReportComponent.builder(FILE, 1).build());
 
     verifyZeroInteractions(issueLifecycle);
-    CloseableIterator<DefaultIssue> issues = issueCache.traverse();
+    CloseableIterator<DefaultIssue> issues = protoIssueCache.traverse();
     assertThat(issues.hasNext()).isFalse();
   }
 }
diff --git a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/issue/IntegrateIssuesVisitorTest.java b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/issue/IntegrateIssuesVisitorTest.java
index 2c8dff9c260..3f228813d62 100644
--- a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/issue/IntegrateIssuesVisitorTest.java
+++ b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/issue/IntegrateIssuesVisitorTest.java
@@ -19,6 +19,7 @@
  */
 package org.sonar.ce.task.projectanalysis.issue;
 
+import java.util.Date;
 import java.util.List;
 import java.util.Optional;
 import org.junit.Before;
@@ -50,6 +51,8 @@ import org.sonar.ce.task.projectanalysis.source.NewLinesRepository;
 import org.sonar.ce.task.projectanalysis.source.SourceLinesHashRepository;
 import org.sonar.ce.task.projectanalysis.source.SourceLinesRepositoryRule;
 import org.sonar.core.issue.DefaultIssue;
+import org.sonar.core.issue.FieldDiffs;
+import org.sonar.core.issue.IssueChangeContext;
 import org.sonar.core.issue.tracking.Tracker;
 import org.sonar.db.DbClient;
 import org.sonar.db.DbTester;
@@ -63,11 +66,13 @@ import org.sonar.db.rule.RuleTesting;
 import org.sonar.scanner.protocol.Constants;
 import org.sonar.scanner.protocol.output.ScannerReport;
 import org.sonar.server.issue.IssueFieldsSetter;
+import org.sonar.server.issue.workflow.IssueWorkflow;
 
 import static com.google.common.collect.Lists.newArrayList;
 import static java.util.Arrays.asList;
 import static java.util.Collections.singletonList;
 import static org.assertj.core.api.Assertions.assertThat;
+import static org.assertj.core.api.Assertions.entry;
 import static org.mockito.ArgumentMatchers.any;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
@@ -114,7 +119,9 @@ public class IntegrateIssuesVisitorTest {
   private AnalysisMetadataHolder analysisMetadataHolder = mock(AnalysisMetadataHolder.class);
   private IssueFilter issueFilter = mock(IssueFilter.class);
   private MovedFilesRepository movedFilesRepository = mock(MovedFilesRepository.class);
-  private IssueLifecycle issueLifecycle = mock(IssueLifecycle.class);
+  private IssueChangeContext issueChangeContext = mock(IssueChangeContext.class);
+  private IssueLifecycle issueLifecycle = new IssueLifecycle(analysisMetadataHolder, issueChangeContext, mock(IssueWorkflow.class), new IssueFieldsSetter(),
+    mock(DebtCalculator.class), ruleRepositoryRule);
   private IssueVisitor issueVisitor = mock(IssueVisitor.class);
   private ReferenceBranchComponentUuids mergeBranchComponentsUuids = mock(ReferenceBranchComponentUuids.class);
   private SiblingsIssueMerger issueStatusCopier = mock(SiblingsIssueMerger.class);
@@ -131,7 +138,7 @@ public class IntegrateIssuesVisitorTest {
   private PullRequestTrackerExecution prBranchTracker;
   private ReferenceBranchTrackerExecution mergeBranchTracker;
   private ActiveRulesHolder activeRulesHolder = new AlwaysActiveRulesHolderImpl();
-  private IssueCache issueCache;
+  private ProtoIssueCache protoIssueCache;
 
   private TypeAwareVisitor underTest;
 
@@ -154,13 +161,15 @@ public class IntegrateIssuesVisitorTest {
     mergeBranchTracker = new ReferenceBranchTrackerExecution(rawInputFactory, mergeInputFactory, new Tracker<>());
     trackingDelegator = new IssueTrackingDelegator(prBranchTracker, mergeBranchTracker, tracker, analysisMetadataHolder);
     treeRootHolder.setRoot(PROJECT);
-    issueCache = new IssueCache(temp.newFile(), System2.INSTANCE);
+    protoIssueCache = new ProtoIssueCache(temp.newFile(), System2.INSTANCE);
     when(issueFilter.accept(any(DefaultIssue.class), eq(FILE))).thenReturn(true);
-    underTest = new IntegrateIssuesVisitor(issueCache, issueLifecycle, issueVisitors, trackingDelegator, issueStatusCopier, referenceBranchComponentUuids);
+    when(issueChangeContext.date()).thenReturn(new Date());
+    underTest = new IntegrateIssuesVisitor(protoIssueCache, issueLifecycle, issueVisitors, trackingDelegator, issueStatusCopier, referenceBranchComponentUuids);
   }
 
   @Test
   public void process_new_issue() {
+    ruleRepositoryRule.add(RuleKey.of("xoo", "S001"));
     when(analysisMetadataHolder.isBranch()).thenReturn(true);
     ScannerReport.Issue reportIssue = ScannerReport.Issue.newBuilder()
       .setMsg("the message")
@@ -173,19 +182,36 @@ public class IntegrateIssuesVisitorTest {
 
     underTest.visitAny(FILE);
 
-    verify(issueLifecycle).initNewOpenIssue(defaultIssueCaptor.capture());
-    DefaultIssue capturedIssue = defaultIssueCaptor.getValue();
-    assertThat(capturedIssue.ruleKey().rule()).isEqualTo("S001");
+    assertThat(newArrayList(protoIssueCache.traverse())).hasSize(1);
+  }
 
-    verify(issueStatusCopier).tryMerge(FILE, singletonList(capturedIssue));
+  @Test
+  public void process_existing_issue() {
 
-    verify(issueLifecycle).doAutomaticTransition(capturedIssue);
+    RuleKey ruleKey = RuleTesting.XOO_X1;
+    // Issue from db has severity major
+    addBaseIssue(ruleKey);
+
+    // Issue from report has severity blocker
+    ScannerReport.Issue reportIssue = ScannerReport.Issue.newBuilder()
+      .setMsg("new message")
+      .setRuleRepository(ruleKey.repository())
+      .setRuleKey(ruleKey.rule())
+      .setSeverity(Constants.Severity.BLOCKER)
+      .build();
+    reportReader.putIssues(FILE_REF, asList(reportIssue));
+    fileSourceRepository.addLine(FILE_REF, "line1");
+
+    underTest.visitAny(FILE);
+
+    List<DefaultIssue> issues = newArrayList(protoIssueCache.traverse());
+    assertThat(issues).hasSize(1);
+    assertThat(issues.get(0).severity()).isEqualTo(Severity.BLOCKER);
 
-    assertThat(newArrayList(issueCache.traverse())).hasSize(1);
   }
 
   @Test
-  public void process_existing_issue() {
+  public void dont_cache_existing_issue_if_unmodified() {
 
     RuleKey ruleKey = RuleTesting.XOO_X1;
     // Issue from db has severity major
@@ -203,15 +229,7 @@ public class IntegrateIssuesVisitorTest {
 
     underTest.visitAny(FILE);
 
-    ArgumentCaptor<DefaultIssue> rawIssueCaptor = ArgumentCaptor.forClass(DefaultIssue.class);
-    ArgumentCaptor<DefaultIssue> baseIssueCaptor = ArgumentCaptor.forClass(DefaultIssue.class);
-    verify(issueLifecycle).mergeExistingOpenIssue(rawIssueCaptor.capture(), baseIssueCaptor.capture());
-    assertThat(rawIssueCaptor.getValue().severity()).isEqualTo(Severity.BLOCKER);
-    assertThat(baseIssueCaptor.getValue().severity()).isEqualTo(Severity.MAJOR);
-
-    verify(issueLifecycle).doAutomaticTransition(defaultIssueCaptor.capture());
-    assertThat(defaultIssueCaptor.getValue().ruleKey()).isEqualTo(ruleKey);
-    List<DefaultIssue> issues = newArrayList(issueCache.traverse());
+    List<DefaultIssue> issues = newArrayList(protoIssueCache.traverse());
     assertThat(issues).hasSize(1);
     assertThat(issues.get(0).severity()).isEqualTo(Severity.BLOCKER);
 
@@ -219,6 +237,7 @@ public class IntegrateIssuesVisitorTest {
 
   @Test
   public void execute_issue_visitors() {
+    ruleRepositoryRule.add(RuleKey.of("xoo", "S001"));
     ScannerReport.Issue reportIssue = ScannerReport.Issue.newBuilder()
       .setMsg("the message")
       .setRuleRepository("xoo")
@@ -242,13 +261,10 @@ public class IntegrateIssuesVisitorTest {
     addBaseIssue(ruleKey);
 
     // No issue in the report
-
     underTest.visitAny(FILE);
 
-    verify(issueLifecycle).doAutomaticTransition(defaultIssueCaptor.capture());
-    assertThat(defaultIssueCaptor.getValue().isBeingClosed()).isTrue();
-    List<DefaultIssue> issues = newArrayList(issueCache.traverse());
-    assertThat(issues).hasSize(1);
+    List<DefaultIssue> issues = newArrayList(protoIssueCache.traverse());
+    assertThat(issues).hasSize(0);
   }
 
   @Test
@@ -289,17 +305,13 @@ public class IntegrateIssuesVisitorTest {
 
     underTest.visitAny(FILE);
 
-    ArgumentCaptor<DefaultIssue> rawIssueCaptor = ArgumentCaptor.forClass(DefaultIssue.class);
-    ArgumentCaptor<DefaultIssue> baseIssueCaptor = ArgumentCaptor.forClass(DefaultIssue.class);
-    verify(issueLifecycle).copyExistingOpenIssueFromBranch(rawIssueCaptor.capture(), baseIssueCaptor.capture(), eq("master"));
-    assertThat(rawIssueCaptor.getValue().severity()).isEqualTo(Severity.BLOCKER);
-    assertThat(baseIssueCaptor.getValue().severity()).isEqualTo(Severity.MAJOR);
-
-    verify(issueLifecycle).doAutomaticTransition(defaultIssueCaptor.capture());
-    assertThat(defaultIssueCaptor.getValue().ruleKey()).isEqualTo(ruleKey);
-    List<DefaultIssue> issues = newArrayList(issueCache.traverse());
+    List<DefaultIssue> issues = newArrayList(protoIssueCache.traverse());
     assertThat(issues).hasSize(1);
     assertThat(issues.get(0).severity()).isEqualTo(Severity.BLOCKER);
+    assertThat(issues.get(0).isNew()).isFalse();
+    assertThat(issues.get(0).isCopied()).isTrue();
+    assertThat(issues.get(0).changes()).hasSize(1);
+    assertThat(issues.get(0).changes().get(0).diffs()).contains(entry(IssueFieldsSetter.FROM_BRANCH, new FieldDiffs.Diff("master",null)));
   }
 
   private void addBaseIssue(RuleKey ruleKey) {
diff --git a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/step/PersistIssuesStepTest.java b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/step/PersistIssuesStepTest.java
index 71ab05babeb..5941fe60b4e 100644
--- a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/step/PersistIssuesStepTest.java
+++ b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/step/PersistIssuesStepTest.java
@@ -34,7 +34,7 @@ import org.sonar.api.utils.System2;
 import org.sonar.ce.task.projectanalysis.analysis.AnalysisMetadataHolderRule;
 import org.sonar.ce.task.projectanalysis.batch.BatchReportReaderRule;
 import org.sonar.ce.task.projectanalysis.issue.AdHocRuleCreator;
-import org.sonar.ce.task.projectanalysis.issue.IssueCache;
+import org.sonar.ce.task.projectanalysis.issue.ProtoIssueCache;
 import org.sonar.ce.task.projectanalysis.issue.RuleRepositoryImpl;
 import org.sonar.ce.task.projectanalysis.issue.UpdateConflictResolver;
 import org.sonar.ce.task.projectanalysis.util.cache.DiskCache;
@@ -60,6 +60,7 @@ import static java.util.Collections.singletonList;
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.assertj.core.data.MapEntry.entry;
 import static org.mockito.ArgumentMatchers.any;
+import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.verify;
@@ -88,7 +89,7 @@ public class PersistIssuesStepTest extends BaseStepTest {
   private DbSession session = db.getSession();
   private DbClient dbClient = db.getDbClient();
   private UpdateConflictResolver conflictResolver = mock(UpdateConflictResolver.class);
-  private IssueCache issueCache;
+  private ProtoIssueCache protoIssueCache;
   private ComputationStep underTest;
 
   private AdHocRuleCreator adHocRuleCreator = mock(AdHocRuleCreator.class);
@@ -100,10 +101,10 @@ public class PersistIssuesStepTest extends BaseStepTest {
 
   @Before
   public void setup() throws Exception {
-    issueCache = new IssueCache(temp.newFile(), System2.INSTANCE);
+    protoIssueCache = new ProtoIssueCache(temp.newFile(), System2.INSTANCE);
     reportReader.setMetadata(ScannerReport.Metadata.getDefaultInstance());
 
-    underTest = new PersistIssuesStep(dbClient, system2, conflictResolver, new RuleRepositoryImpl(adHocRuleCreator, dbClient, analysisMetadataHolder), issueCache,
+    underTest = new PersistIssuesStep(dbClient, system2, conflictResolver, new RuleRepositoryImpl(adHocRuleCreator, dbClient, analysisMetadataHolder), protoIssueCache,
       new IssueStorage());
   }
 
@@ -121,17 +122,20 @@ public class PersistIssuesStepTest extends BaseStepTest {
     ComponentDto file = db.components().insertComponent(newFileDto(project, null));
     when(system2.now()).thenReturn(NOW);
 
-    issueCache.newAppender().append(new DefaultIssue()
+    protoIssueCache.newAppender().append(new DefaultIssue()
       .setKey("ISSUE")
       .setType(RuleType.CODE_SMELL)
       .setRuleKey(rule.getKey())
       .setComponentUuid(file.uuid())
+      .setComponentKey(file.getKey())
       .setProjectUuid(project.uuid())
+      .setProjectKey(project.getKey())
       .setSeverity(BLOCKER)
       .setStatus(STATUS_OPEN)
       .setNew(false)
       .setCopied(true)
       .setType(RuleType.BUG)
+      .setCreationDate(new Date(NOW))
       .setSelectedAt(NOW)
       .addComment(new DefaultIssueComment()
         .setKey("COMMENT")
@@ -139,6 +143,7 @@ public class PersistIssuesStepTest extends BaseStepTest {
         .setUserUuid("john_uuid")
         .setMarkdownText("Some text")
         .setCreatedAt(new Date(NOW))
+        .setUpdatedAt(new Date(NOW))
         .setNew(true))
       .setCurrentChange(
         new FieldDiffs()
@@ -162,8 +167,8 @@ public class PersistIssuesStepTest extends BaseStepTest {
 
     List<IssueChangeDto> changes = dbClient.issueChangeDao().selectByIssueKeys(session, Arrays.asList("ISSUE"));
     assertThat(changes).extracting(IssueChangeDto::getChangeType).containsExactly(IssueChangeDto.TYPE_COMMENT, IssueChangeDto.TYPE_FIELD_CHANGE);
-    assertThat(context.getStatistics().getAll()).containsOnly(
-      entry("inserts", "1"), entry("updates", "0"), entry("merged", "0"), entry("untouched", "0"));
+    assertThat(context.getStatistics().getAll()).contains(
+      entry("inserts", "1"), entry("updates", "0"), entry("merged", "0"));
   }
 
   @Test
@@ -175,23 +180,27 @@ public class PersistIssuesStepTest extends BaseStepTest {
     ComponentDto file = db.components().insertComponent(newFileDto(project, null));
     when(system2.now()).thenReturn(NOW);
 
-    issueCache.newAppender().append(new DefaultIssue()
+    protoIssueCache.newAppender().append(new DefaultIssue()
       .setKey("ISSUE")
       .setType(RuleType.CODE_SMELL)
       .setRuleKey(rule.getKey())
       .setComponentUuid(file.uuid())
+      .setComponentKey(file.getKey())
       .setProjectUuid(project.uuid())
+      .setProjectKey(project.getKey())
       .setSeverity(BLOCKER)
       .setStatus(STATUS_OPEN)
       .setNew(true)
       .setCopied(true)
       .setType(RuleType.BUG)
+      .setCreationDate(new Date(NOW))
       .setSelectedAt(NOW)
       .addComment(new DefaultIssueComment()
         .setKey("COMMENT")
         .setIssueKey("ISSUE")
         .setUserUuid("john_uuid")
         .setMarkdownText("Some text")
+        .setUpdatedAt(new Date(NOW))
         .setCreatedAt(new Date(NOW))
         .setNew(true))
       .setCurrentChange(new FieldDiffs()
@@ -215,8 +224,8 @@ public class PersistIssuesStepTest extends BaseStepTest {
 
     List<IssueChangeDto> changes = dbClient.issueChangeDao().selectByIssueKeys(session, Arrays.asList("ISSUE"));
     assertThat(changes).extracting(IssueChangeDto::getChangeType).containsExactly(IssueChangeDto.TYPE_COMMENT, IssueChangeDto.TYPE_FIELD_CHANGE);
-    assertThat(context.getStatistics().getAll()).containsOnly(
-      entry("inserts", "1"), entry("updates", "0"), entry("merged", "0"), entry("untouched", "0"));
+    assertThat(context.getStatistics().getAll()).contains(
+      entry("inserts", "1"), entry("updates", "0"), entry("merged", "0"));
   }
 
   @Test
@@ -233,7 +242,7 @@ public class PersistIssuesStepTest extends BaseStepTest {
         // simulate the issue has been updated after the analysis ran
         .setUpdatedAt(NOW + 1_000_000_000L));
     issue = dbClient.issueDao().selectByKey(db.getSession(), issue.getKey()).get();
-    DiskCache<DefaultIssue>.DiskAppender issueCacheAppender = issueCache.newAppender();
+    DiskCache.CacheAppender issueCacheAppender = protoIssueCache.newAppender();
     when(system2.now()).thenReturn(NOW);
 
     DefaultIssue defaultIssue = issue.toDefaultIssue()
@@ -250,8 +259,8 @@ public class PersistIssuesStepTest extends BaseStepTest {
     ArgumentCaptor<IssueDto> issueDtoCaptor = ArgumentCaptor.forClass(IssueDto.class);
     verify(conflictResolver).resolve(eq(defaultIssue), issueDtoCaptor.capture(), any(IssueMapper.class));
     assertThat(issueDtoCaptor.getValue().getId()).isEqualTo(issue.getId());
-    assertThat(context.getStatistics().getAll()).containsOnly(
-      entry("inserts", "0"), entry("updates", "1"), entry("merged", "1"), entry("untouched", "0"));
+    assertThat(context.getStatistics().getAll()).contains(
+      entry("inserts", "0"), entry("updates", "1"), entry("merged", "1"));
 
   }
 
@@ -264,14 +273,17 @@ public class PersistIssuesStepTest extends BaseStepTest {
     ComponentDto file = db.components().insertComponent(newFileDto(project, null));
     session.commit();
 
-    issueCache.newAppender().append(new DefaultIssue()
+    protoIssueCache.newAppender().append(new DefaultIssue()
       .setKey("ISSUE")
       .setType(RuleType.CODE_SMELL)
       .setRuleKey(rule.getKey())
       .setComponentUuid(file.uuid())
+      .setComponentKey(file.getKey())
       .setProjectUuid(project.uuid())
+      .setProjectKey(project.getKey())
       .setSeverity(BLOCKER)
       .setStatus(STATUS_OPEN)
+      .setCreationDate(new Date(NOW))
       .setNew(true)
       .setType(RuleType.BUG)).close();
 
@@ -286,8 +298,8 @@ public class PersistIssuesStepTest extends BaseStepTest {
     assertThat(result.getSeverity()).isEqualTo(BLOCKER);
     assertThat(result.getStatus()).isEqualTo(STATUS_OPEN);
     assertThat(result.getType()).isEqualTo(RuleType.BUG.getDbConstant());
-    assertThat(context.getStatistics().getAll()).containsOnly(
-      entry("inserts", "1"), entry("updates", "0"), entry("merged", "0"), entry("untouched", "0"));
+    assertThat(context.getStatistics().getAll()).contains(
+      entry("inserts", "1"), entry("updates", "0"), entry("merged", "0"));
   }
 
   @Test
@@ -300,7 +312,7 @@ public class PersistIssuesStepTest extends BaseStepTest {
         .setResolution(null)
         .setCreatedAt(NOW - 1_000_000_000L)
         .setUpdatedAt(NOW - 1_000_000_000L));
-    DiskCache<DefaultIssue>.DiskAppender issueCacheAppender = issueCache.newAppender();
+    DiskCache.CacheAppender issueCacheAppender = protoIssueCache.newAppender();
 
     issueCacheAppender.append(
       issue.toDefaultIssue()
@@ -317,8 +329,8 @@ public class PersistIssuesStepTest extends BaseStepTest {
     IssueDto issueReloaded = db.getDbClient().issueDao().selectByKey(db.getSession(), issue.getKey()).get();
     assertThat(issueReloaded.getStatus()).isEqualTo(STATUS_CLOSED);
     assertThat(issueReloaded.getResolution()).isEqualTo(RESOLUTION_FIXED);
-    assertThat(context.getStatistics().getAll()).containsOnly(
-      entry("inserts", "0"), entry("updates", "1"), entry("merged", "0"), entry("untouched", "0"));
+    assertThat(context.getStatistics().getAll()).contains(
+      entry("inserts", "0"), entry("updates", "1"), entry("merged", "0"));
   }
 
   @Test
@@ -331,7 +343,7 @@ public class PersistIssuesStepTest extends BaseStepTest {
         .setResolution(null)
         .setCreatedAt(NOW - 1_000_000_000L)
         .setUpdatedAt(NOW - 1_000_000_000L));
-    DiskCache<DefaultIssue>.DiskAppender issueCacheAppender = issueCache.newAppender();
+    DiskCache.CacheAppender issueCacheAppender = protoIssueCache.newAppender();
 
     issueCacheAppender.append(
       issue.toDefaultIssue()
@@ -346,6 +358,7 @@ public class PersistIssuesStepTest extends BaseStepTest {
           .setUserUuid("john_uuid")
           .setMarkdownText("Some text")
           .setCreatedAt(new Date(NOW))
+          .setUpdatedAt(new Date(NOW))
           .setNew(true)))
       .close();
 
@@ -357,8 +370,8 @@ public class PersistIssuesStepTest extends BaseStepTest {
       .extracting(IssueChangeDto::getChangeType, IssueChangeDto::getUserUuid, IssueChangeDto::getChangeData, IssueChangeDto::getIssueKey,
         IssueChangeDto::getIssueChangeCreationDate)
       .containsOnly(IssueChangeDto.TYPE_COMMENT, "john_uuid", "Some text", issue.getKey(), NOW);
-    assertThat(context.getStatistics().getAll()).containsOnly(
-      entry("inserts", "0"), entry("updates", "1"), entry("merged", "0"), entry("untouched", "0"));
+    assertThat(context.getStatistics().getAll()).contains(
+      entry("inserts", "0"), entry("updates", "1"), entry("merged", "0"));
   }
 
   @Test
@@ -371,7 +384,7 @@ public class PersistIssuesStepTest extends BaseStepTest {
         .setResolution(null)
         .setCreatedAt(NOW - 1_000_000_000L)
         .setUpdatedAt(NOW - 1_000_000_000L));
-    DiskCache<DefaultIssue>.DiskAppender issueCacheAppender = issueCache.newAppender();
+    DiskCache.CacheAppender issueCacheAppender = protoIssueCache.newAppender();
 
     issueCacheAppender.append(
       issue.toDefaultIssue()
@@ -395,8 +408,8 @@ public class PersistIssuesStepTest extends BaseStepTest {
       .extracting(IssueChangeDto::getChangeType, IssueChangeDto::getUserUuid, IssueChangeDto::getChangeData, IssueChangeDto::getIssueKey,
         IssueChangeDto::getIssueChangeCreationDate)
       .containsOnly(IssueChangeDto.TYPE_FIELD_CHANGE, "john_uuid", "technicalDebt=1", issue.getKey(), NOW);
-    assertThat(context.getStatistics().getAll()).containsOnly(
-      entry("inserts", "0"), entry("updates", "1"), entry("merged", "0"), entry("untouched", "0"));
+    assertThat(context.getStatistics().getAll()).contains(
+      entry("inserts", "0"), entry("updates", "1"), entry("merged", "0"));
   }
 
 }
diff --git a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/step/SendIssueNotificationsStepTest.java b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/step/SendIssueNotificationsStepTest.java
index 11be48ed072..91ddd0ada48 100644
--- a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/step/SendIssueNotificationsStepTest.java
+++ b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/step/SendIssueNotificationsStepTest.java
@@ -42,6 +42,7 @@ import org.mockito.ArgumentCaptor;
 import org.mockito.invocation.InvocationOnMock;
 import org.mockito.stubbing.Answer;
 import org.sonar.api.notifications.Notification;
+import org.sonar.api.rule.RuleKey;
 import org.sonar.api.rules.RuleType;
 import org.sonar.api.utils.Duration;
 import org.sonar.api.utils.System2;
@@ -50,7 +51,7 @@ import org.sonar.ce.task.projectanalysis.analysis.Branch;
 import org.sonar.ce.task.projectanalysis.component.Component;
 import org.sonar.ce.task.projectanalysis.component.DefaultBranchImpl;
 import org.sonar.ce.task.projectanalysis.component.TreeRootHolderRule;
-import org.sonar.ce.task.projectanalysis.issue.IssueCache;
+import org.sonar.ce.task.projectanalysis.issue.ProtoIssueCache;
 import org.sonar.ce.task.projectanalysis.notification.NotificationFactory;
 import org.sonar.ce.task.projectanalysis.util.cache.DiskCache;
 import org.sonar.ce.task.step.ComputationStep;
@@ -85,6 +86,7 @@ import static org.mockito.ArgumentMatchers.anyMap;
 import static org.mockito.ArgumentMatchers.anySet;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.Mockito.any;
+import static org.mockito.Mockito.doReturn;
 import static org.mockito.Mockito.mock;
 import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.times;
@@ -150,13 +152,13 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
   private NewIssuesNotification newIssuesNotificationMock = createNewIssuesNotificationMock();
   private MyNewIssuesNotification myNewIssuesNotificationMock = createMyNewIssuesNotificationMock();
 
-  private IssueCache issueCache;
+  private ProtoIssueCache protoIssueCache;
   private SendIssueNotificationsStep underTest;
 
   @Before
   public void setUp() throws Exception {
-    issueCache = new IssueCache(temp.newFile(), System2.INSTANCE);
-    underTest = new SendIssueNotificationsStep(issueCache, treeRootHolder, notificationService, analysisMetadataHolder,
+    protoIssueCache = new ProtoIssueCache(temp.newFile(), System2.INSTANCE);
+    underTest = new SendIssueNotificationsStep(protoIssueCache, treeRootHolder, notificationService, analysisMetadataHolder,
       notificationFactory, db.getDbClient());
     when(notificationFactory.newNewIssuesNotification(any(assigneeCacheType))).thenReturn(newIssuesNotificationMock);
     when(notificationFactory.newMyNewIssuesNotification(any(assigneeCacheType))).thenReturn(myNewIssuesNotificationMock);
@@ -178,8 +180,8 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
   @Test
   public void send_global_new_issues_notification() {
     analysisMetadataHolder.setProject(new Project(PROJECT.getUuid(), PROJECT.getKey(), PROJECT.getName(), null, emptyList()));
-    issueCache.newAppender().append(
-      new DefaultIssue().setType(randomRuleType).setEffort(ISSUE_DURATION)
+    protoIssueCache.newAppender().append(
+      createIssue().setType(randomRuleType).setEffort(ISSUE_DURATION)
         .setCreationDate(new Date(ANALYSE_DATE)))
       .close();
     when(notificationService.hasProjectSubscribersForTypes(eq(PROJECT.getUuid()), any())).thenReturn(true);
@@ -202,15 +204,16 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
     Integer[] backDatedEfforts = IntStream.range(0, 1 + random.nextInt(10)).mapToObj(i -> 10 + random.nextInt(100)).toArray(Integer[]::new);
     Duration expectedEffort = Duration.create(stream(efforts).mapToInt(i -> i).sum());
     List<DefaultIssue> issues = concat(stream(efforts)
-        .map(effort -> new DefaultIssue().setType(randomRuleType).setEffort(Duration.create(effort))
+        .map(effort -> createIssue().setType(randomRuleType).setEffort(Duration.create(effort))
           .setCreationDate(new Date(ANALYSE_DATE))),
       stream(backDatedEfforts)
-        .map(effort -> new DefaultIssue().setType(randomRuleType).setEffort(Duration.create(effort))
+        .map(effort -> createIssue().setType(randomRuleType).setEffort(Duration.create(effort))
           .setCreationDate(new Date(ANALYSE_DATE - FIVE_MINUTES_IN_MS))))
       .collect(toList());
     shuffle(issues);
-    DiskCache<DefaultIssue>.DiskAppender issueCache = this.issueCache.newAppender();
+    DiskCache.CacheAppender issueCache = this.protoIssueCache.newAppender();
     issues.forEach(issueCache::append);
+    issueCache.close();
     analysisMetadataHolder.setProject(new Project(PROJECT.getUuid(), PROJECT.getKey(), PROJECT.getName(), null, emptyList()));
     when(notificationService.hasProjectSubscribersForTypes(PROJECT.getUuid(), NOTIF_TYPES)).thenReturn(true);
 
@@ -233,8 +236,8 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
   @Test
   public void do_not_send_global_new_issues_notification_if_issue_has_been_backdated() {
     analysisMetadataHolder.setProject(new Project(PROJECT.getUuid(), PROJECT.getKey(), PROJECT.getName(), null, emptyList()));
-    issueCache.newAppender().append(
-      new DefaultIssue().setType(randomRuleType).setEffort(ISSUE_DURATION)
+    protoIssueCache.newAppender().append(
+      createIssue().setType(randomRuleType).setEffort(ISSUE_DURATION)
         .setCreationDate(new Date(ANALYSE_DATE - FIVE_MINUTES_IN_MS)))
       .close();
     when(notificationService.hasProjectSubscribersForTypes(PROJECT.getUuid(), NOTIF_TYPES)).thenReturn(true);
@@ -251,8 +254,8 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
   public void send_global_new_issues_notification_on_branch() {
     ComponentDto project = newPrivateProjectDto(newOrganizationDto());
     ComponentDto branch = setUpBranch(project, BRANCH);
-    issueCache.newAppender().append(
-      new DefaultIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setCreationDate(new Date(ANALYSE_DATE))).close();
+    protoIssueCache.newAppender().append(
+      createIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setCreationDate(new Date(ANALYSE_DATE))).close();
     when(notificationService.hasProjectSubscribersForTypes(branch.uuid(), NOTIF_TYPES)).thenReturn(true);
     analysisMetadataHolder.setProject(Project.from(project));
     analysisMetadataHolder.setBranch(newBranch(BranchType.BRANCH));
@@ -272,8 +275,8 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
   public void do_not_send_global_new_issues_notification_on_pull_request() {
     ComponentDto project = newPrivateProjectDto(newOrganizationDto());
     ComponentDto branch = setUpBranch(project, PULL_REQUEST);
-    issueCache.newAppender().append(
-      new DefaultIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setCreationDate(new Date(ANALYSE_DATE))).close();
+    protoIssueCache.newAppender().append(
+      createIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setCreationDate(new Date(ANALYSE_DATE))).close();
     when(notificationService.hasProjectSubscribersForTypes(project.uuid(), NOTIF_TYPES)).thenReturn(true);
     analysisMetadataHolder.setProject(Project.from(project));
     analysisMetadataHolder.setBranch(newPullRequest());
@@ -285,12 +288,16 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
     verifyZeroInteractions(notificationService, newIssuesNotificationMock);
   }
 
+  private DefaultIssue createIssue() {
+    return new DefaultIssue().setKey("k").setProjectKey("p").setStatus("OPEN").setProjectUuid("uuid").setComponentKey("c").setRuleKey(RuleKey.of("r", "r"));
+  }
+
   @Test
   public void do_not_send_global_new_issues_notification_on_branch_if_issue_has_been_backdated() {
     ComponentDto project = newPrivateProjectDto(newOrganizationDto());
     ComponentDto branch = setUpBranch(project, BRANCH);
-    issueCache.newAppender().append(
-      new DefaultIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setCreationDate(new Date(ANALYSE_DATE - FIVE_MINUTES_IN_MS))).close();
+    protoIssueCache.newAppender().append(
+      createIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setCreationDate(new Date(ANALYSE_DATE - FIVE_MINUTES_IN_MS))).close();
     when(notificationService.hasProjectSubscribersForTypes(branch.uuid(), NOTIF_TYPES)).thenReturn(true);
     analysisMetadataHolder.setProject(Project.from(project));
     analysisMetadataHolder.setBranch(newBranch(BranchType.BRANCH));
@@ -308,9 +315,8 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
     UserDto user = db.users().insertUser();
     analysisMetadataHolder.setProject(new Project(PROJECT.getUuid(), PROJECT.getKey(), PROJECT.getName(), null, emptyList()));
 
-    issueCache.newAppender().append(
-      new DefaultIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setAssigneeUuid(user.getUuid())
-        .setCreationDate(new Date(ANALYSE_DATE)))
+    protoIssueCache.newAppender().append(
+      createIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setAssigneeUuid(user.getUuid()).setCreationDate(new Date(ANALYSE_DATE)))
       .close();
     when(notificationService.hasProjectSubscribersForTypes(eq(PROJECT.getUuid()), any())).thenReturn(true);
 
@@ -340,19 +346,21 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
     Integer[] assignedToOther = IntStream.range(0, 3).mapToObj(i -> 10).toArray(Integer[]::new);
 
     List<DefaultIssue> issues = concat(stream(assigned)
-        .map(effort -> new DefaultIssue().setType(randomRuleType).setEffort(Duration.create(effort))
+        .map(effort -> createIssue().setType(randomRuleType).setEffort(Duration.create(effort))
           .setAssigneeUuid(perceval.getUuid())
+          .setNew(true)
           .setCreationDate(new Date(ANALYSE_DATE))),
       stream(assignedToOther)
-        .map(effort -> new DefaultIssue().setType(randomRuleType).setEffort(Duration.create(effort))
+        .map(effort -> createIssue().setType(randomRuleType).setEffort(Duration.create(effort))
           .setAssigneeUuid(arthur.getUuid())
+          .setNew(true)
           .setCreationDate(new Date(ANALYSE_DATE))))
       .collect(toList());
     shuffle(issues);
-    IssueCache issueCache = new IssueCache(temp.newFile(), System2.INSTANCE);
-    DiskCache<DefaultIssue>.DiskAppender newIssueCache = issueCache.newAppender();
+    ProtoIssueCache protoIssueCache = new ProtoIssueCache(temp.newFile(), System2.INSTANCE);
+    DiskCache.CacheAppender newIssueCache = protoIssueCache.newAppender();
     issues.forEach(newIssueCache::append);
-
+    newIssueCache.close();
     analysisMetadataHolder.setProject(new Project(PROJECT.getUuid(), PROJECT.getKey(), PROJECT.getName(), null, emptyList()));
     when(notificationService.hasProjectSubscribersForTypes(PROJECT.getUuid(), NOTIF_TYPES)).thenReturn(true);
 
@@ -363,12 +371,10 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
 
     MyNewIssuesNotification myNewIssuesNotificationMock1 = createMyNewIssuesNotificationMock();
     MyNewIssuesNotification myNewIssuesNotificationMock2 = createMyNewIssuesNotificationMock();
-    when(notificationFactory.newMyNewIssuesNotification(any(assigneeCacheType)))
-      .thenReturn(myNewIssuesNotificationMock1)
-      .thenReturn(myNewIssuesNotificationMock2);
+    doReturn(myNewIssuesNotificationMock1).doReturn(myNewIssuesNotificationMock2).when(notificationFactory).newMyNewIssuesNotification(any(assigneeCacheType));
 
     TestComputationStepContext context = new TestComputationStepContext();
-    new SendIssueNotificationsStep(issueCache, treeRootHolder, notificationService, analysisMetadataHolder, notificationFactory, db.getDbClient())
+    new SendIssueNotificationsStep(protoIssueCache, treeRootHolder, notificationService, analysisMetadataHolder, notificationFactory, db.getDbClient())
       .execute(context);
 
     verify(notificationService).deliverEmails(ImmutableSet.of(myNewIssuesNotificationMock1, myNewIssuesNotificationMock2));
@@ -413,17 +419,18 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
     Integer[] backDatedEfforts = IntStream.range(0, 1 + random.nextInt(10)).mapToObj(i -> 10 + random.nextInt(100)).toArray(Integer[]::new);
     Duration expectedEffort = Duration.create(stream(efforts).mapToInt(i -> i).sum());
     List<DefaultIssue> issues = concat(stream(efforts)
-        .map(effort -> new DefaultIssue().setType(randomRuleType).setEffort(Duration.create(effort))
+        .map(effort -> createIssue().setType(randomRuleType).setEffort(Duration.create(effort))
           .setAssigneeUuid(user.getUuid())
           .setCreationDate(new Date(ANALYSE_DATE))),
       stream(backDatedEfforts)
-        .map(effort -> new DefaultIssue().setType(randomRuleType).setEffort(Duration.create(effort))
+        .map(effort -> createIssue().setType(randomRuleType).setEffort(Duration.create(effort))
           .setAssigneeUuid(user.getUuid())
           .setCreationDate(new Date(ANALYSE_DATE - FIVE_MINUTES_IN_MS))))
       .collect(toList());
     shuffle(issues);
-    DiskCache<DefaultIssue>.DiskAppender issueCache = this.issueCache.newAppender();
+    DiskCache.CacheAppender issueCache = this.protoIssueCache.newAppender();
     issues.forEach(issueCache::append);
+    issueCache.close();
     analysisMetadataHolder.setProject(new Project(PROJECT.getUuid(), PROJECT.getKey(), PROJECT.getName(), null, emptyList()));
     when(notificationService.hasProjectSubscribersForTypes(PROJECT.getUuid(), NOTIF_TYPES)).thenReturn(true);
 
@@ -469,8 +476,8 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
   public void do_not_send_new_issues_notification_to_user_if_issue_is_backdated() {
     analysisMetadataHolder.setProject(new Project(PROJECT.getUuid(), PROJECT.getKey(), PROJECT.getName(), null, emptyList()));
     UserDto user = db.users().insertUser();
-    issueCache.newAppender().append(
-      new DefaultIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setAssigneeUuid(user.getUuid())
+    protoIssueCache.newAppender().append(
+      createIssue().setType(randomRuleType).setEffort(ISSUE_DURATION).setAssigneeUuid(user.getUuid())
         .setCreationDate(new Date(ANALYSE_DATE - FIVE_MINUTES_IN_MS)))
       .close();
     when(notificationService.hasProjectSubscribersForTypes(PROJECT.getUuid(), NOTIF_TYPES)).thenReturn(true);
@@ -543,7 +550,7 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
   private DefaultIssue prepareIssue(long issueCreatedAt, UserDto user, ComponentDto project, ComponentDto file, RuleDefinitionDto ruleDefinitionDto, RuleType type) {
     DefaultIssue issue = newIssue(ruleDefinitionDto, project, file).setType(type).toDefaultIssue()
       .setNew(false).setChanged(true).setSendNotifications(true).setCreationDate(new Date(issueCreatedAt)).setAssigneeUuid(user.getUuid());
-    issueCache.newAppender().append(issue).close();
+    protoIssueCache.newAppender().append(issue).close();
     when(notificationService.hasProjectSubscribersForTypes(project.projectUuid(), NOTIF_TYPES)).thenReturn(true);
     return issue;
   }
@@ -572,7 +579,7 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
       .setChanged(true)
       .setSendNotifications(true)
       .setCreationDate(new Date(issueCreatedAt));
-    issueCache.newAppender().append(issue).close();
+    protoIssueCache.newAppender().append(issue).close();
     when(notificationService.hasProjectSubscribersForTypes(project.uuid(), NOTIF_TYPES)).thenReturn(true);
     IssuesChangesNotification issuesChangesNotification = mock(IssuesChangesNotification.class);
     when(notificationFactory.newIssuesChangesNotification(anySet(), anyMap())).thenReturn(issuesChangesNotification);
@@ -601,9 +608,9 @@ public class SendIssueNotificationsStepTest extends BaseStepTest {
       .mapToObj(i -> newIssue(ruleDefinitionDto, project, file).setKee("uuid_" + i).setType(randomTypeExceptHotspot).toDefaultIssue()
         .setNew(false).setChanged(true).setSendNotifications(true).setAssigneeUuid(user.getUuid()))
       .collect(toList());
-    DiskCache<DefaultIssue>.DiskAppender diskAppender = issueCache.newAppender();
-    issues.forEach(diskAppender::append);
-    diskAppender.close();
+    DiskCache.CacheAppender cacheAppender = protoIssueCache.newAppender();
+    issues.forEach(cacheAppender::append);
+    cacheAppender.close();
     analysisMetadataHolder.setProject(Project.from(project));
     NewIssuesFactoryCaptor newIssuesFactoryCaptor = new NewIssuesFactoryCaptor(() -> mock(IssuesChangesNotification.class));
     when(notificationFactory.newIssuesChangesNotification(anySet(), anyMap())).thenAnswer(newIssuesFactoryCaptor);
diff --git a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/util/cache/DiskCacheTest.java b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/util/cache/JavaSerializationDiskCacheTest.java
index 5197ad323be..c9e712bfc09 100644
--- a/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/util/cache/DiskCacheTest.java
+++ b/server/sonar-ce-task-projectanalysis/src/test/java/org/sonar/ce/task/projectanalysis/util/cache/JavaSerializationDiskCacheTest.java
@@ -19,26 +19,25 @@
  */
 package org.sonar.ce.task.projectanalysis.util.cache;
 
+import java.io.ObjectOutputStream;
+import java.io.Serializable;
 import org.junit.Rule;
 import org.junit.Test;
 import org.junit.rules.TemporaryFolder;
 import org.sonar.api.utils.System2;
 import org.sonar.core.util.CloseableIterator;
 
-import java.io.ObjectOutputStream;
-import java.io.Serializable;
-
 import static org.assertj.core.api.Assertions.assertThat;
 import static org.junit.Assert.fail;
 
-public class DiskCacheTest {
+public class JavaSerializationDiskCacheTest {
 
   @Rule
   public TemporaryFolder temp = new TemporaryFolder();
 
   @Test
   public void write_and_read() throws Exception {
-    DiskCache<String> cache = new DiskCache<>(temp.newFile(), System2.INSTANCE);
+    DiskCache<String> cache = new JavaSerializationDiskCache<>(temp.newFile(), System2.INSTANCE);
     try (CloseableIterator<String> traverse = cache.traverse()) {
       assertThat(traverse).isExhausted();
     }
@@ -55,7 +54,7 @@ public class DiskCacheTest {
   @Test
   public void fail_if_file_is_not_writable() throws Exception {
     try {
-      new DiskCache<>(temp.newFolder(), System2.INSTANCE);
+      new JavaSerializationDiskCache<>(temp.newFolder(), System2.INSTANCE);
       fail();
     } catch (IllegalStateException e) {
       assertThat(e).hasMessageContaining("Fail to write into file");
@@ -69,7 +68,7 @@ public class DiskCacheTest {
         throw new UnsupportedOperationException("expected error");
       }
     }
-    DiskCache<Serializable> cache = new DiskCache<>(temp.newFile(), System2.INSTANCE);
+    DiskCache<Serializable> cache = new JavaSerializationDiskCache<>(temp.newFile(), System2.INSTANCE);
     try {
       cache.newAppender().append(new Unserializable());
       fail();
diff --git a/server/sonar-db-dao/build.gradle b/server/sonar-db-dao/build.gradle
index 6877e8d4eba..2b0f2d86f6e 100644
--- a/server/sonar-db-dao/build.gradle
+++ b/server/sonar-db-dao/build.gradle
@@ -76,3 +76,8 @@ configurations {
 artifacts {
    tests testJar
 }
+
+jar {
+    // remove exclusion on proto files so that they can be included by other modules
+    setExcludes([])
+}
diff --git a/sonar-core/src/main/java/org/sonar/core/issue/DefaultIssue.java b/sonar-core/src/main/java/org/sonar/core/issue/DefaultIssue.java
index 5a81de71b63..cd91a5d4fbe 100644
--- a/sonar-core/src/main/java/org/sonar/core/issue/DefaultIssue.java
+++ b/sonar-core/src/main/java/org/sonar/core/issue/DefaultIssue.java
@@ -213,11 +213,12 @@ public class DefaultIssue implements Issue, Trackable, org.sonar.api.ce.measure.
   }
 
   @Override
+  @CheckForNull
   public String language() {
     return language;
   }
 
-  public DefaultIssue setLanguage(String l) {
+  public DefaultIssue setLanguage(@Nullable String l) {
     this.language = l;
     return this;
   }
@@ -269,7 +270,7 @@ public class DefaultIssue implements Issue, Trackable, org.sonar.api.ce.measure.
   }
 
   public DefaultIssue setLine(@Nullable Integer l) {
-    Preconditions.checkArgument(l == null || l > 0, "Line must be null or greater than zero (got %d)", l);
+    Preconditions.checkArgument(l == null || l > 0, "Line must be null or greater than zero (got %s)", l);
     this.line = l;
     return this;
   }
@@ -507,6 +508,11 @@ public class DefaultIssue implements Issue, Trackable, org.sonar.api.ce.measure.
     return this;
   }
 
+  public DefaultIssue setCurrentChangeWithoutAddChange(@Nullable FieldDiffs currentChange) {
+    this.currentChange = currentChange;
+    return this;
+  }
+
   @CheckForNull
   public FieldDiffs currentChange() {
     return currentChange;
@@ -583,7 +589,7 @@ public class DefaultIssue implements Issue, Trackable, org.sonar.api.ce.measure.
       return false;
     }
     DefaultIssue that = (DefaultIssue) o;
-    return !(key != null ? !key.equals(that.key) : (that.key != null));
+    return Objects.equals(key, that.key);
   }
 
   @Override
diff --git a/sonar-core/src/main/java/org/sonar/core/issue/FieldDiffs.java b/sonar-core/src/main/java/org/sonar/core/issue/FieldDiffs.java
index d560d79e174..8113a90c610 100644
--- a/sonar-core/src/main/java/org/sonar/core/issue/FieldDiffs.java
+++ b/sonar-core/src/main/java/org/sonar/core/issue/FieldDiffs.java
@@ -85,11 +85,12 @@ public class FieldDiffs implements Serializable {
     return this;
   }
 
+  @CheckForNull
   public String issueKey() {
     return issueKey;
   }
 
-  public FieldDiffs setIssueKey(String issueKey) {
+  public FieldDiffs setIssueKey(@Nullable String issueKey) {
     this.issueKey = issueKey;
     return this;
   }