Store users that starred a change in change index

Within notedb each change that is starred by a user is tracked by a
refs/starred-changes/XX/YYYY/ZZZZ ref in the All-Users meta repository
where XX/YYYY is the sharded change ID and ZZZZ is the account ID.
With this storage format finding all users that have starred a
change is cheap because we just need to list all refs that have
refs/starred-changes/XX/YYYY/ as prefix and looking up refs with a
prefix that ends on '/' is optimized in jgit. However to find all
changes that were starred by a user we must scan the complete
refs/starred-changes/ namespace and check which of the refs end with
the account ID. This results in bad performance when there are many
starred changes. Having the users that starred a change stored in the
change index makes this lookup cheap.

Looking up all changes that were starred by a user is needed for
supporting the "is:starred" query operator and for populating the
"starred" field in ChangeInfo.

Change-Id: Iecc9ca8ef133b0d0f86f1471b9ed31be78a43f6c
Signed-off-by: Edwin Kempin <ekempin@google.com>

gerrit-lucene/src/main/java/com/google/gerrit/lucene/LuceneChangeIndex.java

@@ -114,6 +114,7 @@ public class LuceneChangeIndex implements ChangeIndex {
   private static final String PATCH_SET_FIELD = ChangeField.PATCH_SET.getName();
   private static final String REVIEWEDBY_FIELD =
       ChangeField.REVIEWEDBY.getName();
+  private static final String STARREDBY_FIELD = ChangeField.STARREDBY.getName();
 
   static Term idTerm(ChangeData cd) {
     return QueryBuilder.intTerm(LEGACY_ID.getName(), cd.getId().get());
@@ -413,6 +414,9 @@ public class LuceneChangeIndex implements ChangeIndex {
     if (fields.contains(REVIEWEDBY_FIELD)) {
       decodeReviewedBy(doc, cd);
     }
+    if (fields.contains(STARREDBY_FIELD)) {
+      decodeStarredBy(doc, cd);
+    }
     return cd;
   }
 
@@ -466,6 +470,16 @@ public class LuceneChangeIndex implements ChangeIndex {
     }
   }
 
+  private void decodeStarredBy(Document doc, ChangeData cd) {
+    IndexableField[] starredBy = doc.getFields(STARREDBY_FIELD);
+    Set<Account.Id> accounts =
+        Sets.newHashSetWithExpectedSize(starredBy.length);
+    for (IndexableField r : starredBy) {
+      accounts.add(new Account.Id(r.numericValue().intValue()));
+    }
+    cd.setStarredBy(accounts);
+  }
+
   private static <T> List<T> decodeProtos(Document doc, String fieldName,
       ProtobufCodec<T> codec) {
     BytesRef[] bytesRefs = doc.getBinaryValues(fieldName);

gerrit-server/src/main/java/com/google/gerrit/server/IdentifiedUser.java

@@ -338,7 +338,7 @@ public class IdentifiedUser extends CurrentUser {
             FluentIterable.from(
               starredQuery != null
               ? starredQuery
-              : starredChangesUtil.query(accountId))
+              : starredChangesUtil.queryFromIndex(accountId))
             .toSet();
       } finally {
         starredQuery = null;
@@ -356,7 +356,7 @@ public class IdentifiedUser extends CurrentUser {
 
   public void asyncStarredChanges() {
     if (starredChanges == null && starredChangesUtil != null) {
-      starredQuery = starredChangesUtil.query(accountId);
+      starredQuery = starredChangesUtil.queryFromIndex(accountId);
     }
   }
 

gerrit-server/src/main/java/com/google/gerrit/server/StarredChangesUtil.java

@@ -15,18 +15,24 @@
 package com.google.gerrit.server;
 
 import com.google.common.base.Function;
-import com.google.common.base.Predicate;
 import com.google.common.collect.FluentIterable;
+import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Iterators;
 import com.google.common.collect.Lists;
 import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.reviewdb.client.StarredChange;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.git.GitRepositoryManager;
+import com.google.gerrit.server.index.change.ChangeField;
+import com.google.gerrit.server.index.change.ChangeIndexer;
 import com.google.gerrit.server.notedb.NotesMigration;
+import com.google.gerrit.server.project.NoSuchChangeException;
+import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.server.query.change.InternalChangeQuery;
 import com.google.gwtorm.server.ListResultSet;
 import com.google.gwtorm.server.OrmException;
 import com.google.gwtorm.server.ResultSet;
@@ -65,26 +71,33 @@ public class StarredChangesUtil {
   private final NotesMigration migration;
   private final Provider<ReviewDb> dbProvider;
   private final PersonIdent serverIdent;
+  private final ChangeIndexer indexer;
+  private final Provider<InternalChangeQuery> queryProvider;
 
   @Inject
   StarredChangesUtil(GitRepositoryManager repoManager,
       AllUsersName allUsers,
       NotesMigration migration,
       Provider<ReviewDb> dbProvider,
-      @GerritPersonIdent PersonIdent serverIdent) {
+      @GerritPersonIdent PersonIdent serverIdent,
+      ChangeIndexer indexer,
+      Provider<InternalChangeQuery> queryProvider) {
     this.repoManager = repoManager;
     this.allUsers = allUsers;
     this.migration = migration;
     this.dbProvider = dbProvider;
     this.serverIdent = serverIdent;
+    this.indexer = indexer;
+    this.queryProvider = queryProvider;
   }
 
-  public void star(Account.Id accountId, Change.Id changeId)
+  public void star(Account.Id accountId, Project.NameKey project,
-      throws OrmException {
+      Change.Id changeId) throws OrmException, IOException {
     dbProvider.get().starredChanges()
         .insert(Collections.singleton(new StarredChange(
             new StarredChange.Key(accountId, changeId))));
     if (!migration.writeAccounts()) {
+      indexer.index(dbProvider.get(), project, changeId);
       return;
     }
     try (Repository repo = repoManager.openRepository(allUsers);
@@ -98,6 +111,7 @@ public class StarredChangesUtil {
       RefUpdate.Result result = u.update(rw);
       switch (result) {
         case NEW:
+          indexer.index(dbProvider.get(), project, changeId);
           return;
         case FAST_FORWARD:
         case FORCED:
@@ -128,12 +142,13 @@ public class StarredChangesUtil {
     }
   }
 
-  public void unstar(Account.Id accountId, Change.Id changeId)
+  public void unstar(Account.Id accountId, Project.NameKey project,
-      throws OrmException {
+      Change.Id changeId) throws OrmException, IOException {
     dbProvider.get().starredChanges()
         .delete(Collections.singleton(new StarredChange(
             new StarredChange.Key(accountId, changeId))));
     if (!migration.writeAccounts()) {
+      indexer.index(dbProvider.get(), project, changeId);
       return;
     }
     try (Repository repo = repoManager.openRepository(allUsers);
@@ -146,6 +161,7 @@ public class StarredChangesUtil {
       RefUpdate.Result result = u.delete();
       switch (result) {
         case FORCED:
+          indexer.index(dbProvider.get(), project, changeId);
           return;
         case FAST_FORWARD:
         case IO_FAILURE:
@@ -168,10 +184,12 @@ public class StarredChangesUtil {
     }
   }
 
-  public void unstarAll(Change.Id changeId) throws OrmException {
+  public void unstarAll(Project.NameKey project, Change.Id changeId)
+      throws OrmException, IOException, NoSuchChangeException {
     dbProvider.get().starredChanges().delete(
         dbProvider.get().starredChanges().byChange(changeId));
     if (!migration.writeAccounts()) {
+      indexer.index(dbProvider.get(), project, changeId);
       return;
     }
     try (Repository repo = repoManager.openRepository(allUsers);
@@ -180,7 +198,7 @@ public class StarredChangesUtil {
       batchUpdate.setAllowNonFastForwards(true);
       batchUpdate.setRefLogIdent(serverIdent);
       batchUpdate.setRefLogMessage("Unstar change " + changeId.get(), true);
-      for (Account.Id accountId : byChange(changeId)) {
+      for (Account.Id accountId : byChangeFromIndex(changeId)) {
         String refName = RefNames.refsStarredChanges(changeId, accountId);
         Ref ref = repo.getRefDatabase().getRef(refName);
         batchUpdate.addCommand(new ReceiveCommand(ref.getObjectId(),
@@ -194,13 +212,14 @@ public class StarredChangesUtil {
               changeId.get(), command.getRefName(), command.getResult()));
         }
       }
+      indexer.index(dbProvider.get(), project, changeId);
     } catch (IOException e) {
       throw new OrmException(
           String.format("Unstar change %d failed", changeId.get()), e);
     }
   }
 
-  public Iterable<Account.Id> byChange(Change.Id changeId)
+  public Set<Account.Id> byChange(Change.Id changeId)
       throws OrmException {
     if (!migration.readAccounts()) {
       return FluentIterable
@@ -210,7 +229,7 @@ public class StarredChangesUtil {
             public Account.Id apply(StarredChange in) {
               return in.getAccountId();
             }
-          });
+          }).toSet();
     }
     return FluentIterable
         .from(getRefNames(RefNames.refsStarredChangesPrefix(changeId)))
@@ -219,29 +238,40 @@ public class StarredChangesUtil {
           public Account.Id apply(String refPart) {
             return Account.Id.parse(refPart);
           }
-        });
+        }).toSet();
+  }
+
+  public Set<Account.Id> byChangeFromIndex(Change.Id changeId)
+      throws OrmException, NoSuchChangeException {
+    Set<String> fields = ImmutableSet.of(
+        ChangeField.ID.getName(),
+        ChangeField.STARREDBY.getName());
+    List<ChangeData> changeData = queryProvider.get().setRequestedFields(fields)
+        .byLegacyChangeId(changeId);
+    if (changeData.size() != 1) {
+      throw new NoSuchChangeException(changeId);
+    }
+    return changeData.get(0).starredBy();
   }
 
   @Deprecated
-  public ResultSet<Change.Id> query(final Account.Id accountId) {
+  public ResultSet<Change.Id> queryFromIndex(final Account.Id accountId) {
     try {
       if (!migration.readAccounts()) {
         return new ChangeIdResultSet(
             dbProvider.get().starredChanges().byAccount(accountId));
       }
 
+      Set<String> fields = ImmutableSet.of(
+          ChangeField.ID.getName());
+      List<ChangeData> changeData =
+          queryProvider.get().setRequestedFields(fields).byIsStarred(accountId);
       return new ListResultSet<>(FluentIterable
-          .from(getRefNames(RefNames.REFS_STARRED_CHANGES))
+          .from(changeData)
-          .filter(new Predicate<String>() {
+          .transform(new Function<ChangeData, Change.Id>() {
             @Override
-            public boolean apply(String refPart) {
+            public Change.Id apply(ChangeData cd) {
-              return refPart.endsWith("/" + accountId.get());
+              return cd.getId();
-            }
-          })
-          .transform(new Function<String, Change.Id>() {
-            @Override
-            public Change.Id apply(String changeId) {
-              return Change.Id.parse(changeId);
             }
           }).toList());
     } catch (OrmException | RuntimeException e) {

gerrit-server/src/main/java/com/google/gerrit/server/account/StarredChanges.java

@@ -42,6 +42,8 @@ import com.google.inject.Singleton;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
+import java.io.IOException;
+
 @Singleton
 public class StarredChanges implements
     ChildCollection<AccountResource, AccountResource.StarredChange>,
@@ -130,12 +132,13 @@ public class StarredChanges implements
 
     @Override
     public Response<?> apply(AccountResource rsrc, EmptyInput in)
-        throws AuthException, OrmException {
+        throws AuthException, OrmException, IOException {
       if (self.get() != rsrc.getUser()) {
         throw new AuthException("not allowed to add starred change");
       }
       try {
-        starredChangesUtil.star(self.get().getAccountId(), change.getId());
+        starredChangesUtil.star(self.get().getAccountId(), change.getProject(),
+            change.getId());
       } catch (OrmDuplicateKeyException e) {
         return Response.none();
       }
@@ -177,12 +180,12 @@ public class StarredChanges implements
 
     @Override
     public Response<?> apply(AccountResource.StarredChange rsrc,
-        EmptyInput in) throws AuthException, OrmException {
+        EmptyInput in) throws AuthException, OrmException, IOException {
       if (self.get() != rsrc.getUser()) {
         throw new AuthException("not allowed remove starred change");
       }
       starredChangesUtil.unstar(self.get().getAccountId(),
-          rsrc.getChange().getId());
+          rsrc.getChange().getProject(), rsrc.getChange().getId());
       return Response.none();
     }
   }

gerrit-server/src/main/java/com/google/gerrit/server/api/accounts/AccountApiImpl.java

@@ -193,7 +193,7 @@ public class AccountApiImpl implements AccountApi {
         IdString.fromUrl(id));
       starredChangesCreate.setChange(rsrc);
       starredChangesCreate.apply(account, new StarredChanges.EmptyInput());
-    } catch (OrmException e) {
+    } catch (OrmException | IOException e) {
       throw new RestApiException("Cannot star change", e);
     }
   }
@@ -207,7 +207,7 @@ public class AccountApiImpl implements AccountApi {
           new AccountResource.StarredChange(account.getUser(), rsrc);
       starredChangesDelete.apply(starredChange,
           new StarredChanges.EmptyInput());
-    } catch (OrmException e) {
+    } catch (OrmException | IOException e) {
       throw new RestApiException("Cannot unstar change", e);
     }
   }

gerrit-server/src/main/java/com/google/gerrit/server/change/DeleteDraftChangeOp.java

@@ -31,6 +31,7 @@ import com.google.gerrit.server.git.BatchUpdate;
 import com.google.gerrit.server.git.BatchUpdate.ChangeContext;
 import com.google.gerrit.server.git.BatchUpdate.RepoContext;
 import com.google.gerrit.server.git.BatchUpdateReviewDb;
+import com.google.gerrit.server.project.NoSuchChangeException;
 import com.google.gerrit.server.schema.DisabledChangesReviewDbWrapper;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
@@ -78,8 +79,8 @@ class DeleteDraftChangeOp extends BatchUpdate.Op {
   }
 
   @Override
-  public boolean updateChange(ChangeContext ctx)
+  public boolean updateChange(ChangeContext ctx) throws RestApiException,
-      throws RestApiException, OrmException {
+      OrmException, IOException, NoSuchChangeException {
     checkState(ctx.getOrder() == BatchUpdate.Order.DB_BEFORE_REPO,
         "must use DeleteDraftChangeOp with DB_BEFORE_REPO");
     checkState(id == null, "cannot reuse DeleteDraftChangeOp");
@@ -117,7 +118,7 @@ class DeleteDraftChangeOp extends BatchUpdate.Op {
 
     // Non-atomic operation on Accounts table; not much we can do to make it
     // atomic.
-    starredChangesUtil.unstarAll(id);
+    starredChangesUtil.unstarAll(change.getProject(), id);
 
     ctx.deleteChange();
     return true;

gerrit-server/src/main/java/com/google/gerrit/server/change/DeleteDraftPatchSet.java

@@ -35,6 +35,7 @@ import com.google.gerrit.server.git.BatchUpdate.RepoContext;
 import com.google.gerrit.server.git.UpdateException;
 import com.google.gerrit.server.patch.PatchSetInfoFactory;
 import com.google.gerrit.server.patch.PatchSetInfoNotAvailableException;
+import com.google.gerrit.server.project.NoSuchChangeException;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -99,8 +100,8 @@ public class DeleteDraftPatchSet implements RestModifyView<RevisionResource, Inp
     }
 
     @Override
-    public boolean updateChange(ChangeContext ctx)
+    public boolean updateChange(ChangeContext ctx) throws RestApiException,
-        throws RestApiException, OrmException, IOException {
+        OrmException, IOException, NoSuchChangeException {
       patchSet = psUtil.get(ctx.getDb(), ctx.getNotes(), psId);
       if (patchSet == null) {
         return false; // Nothing to do.
@@ -148,7 +149,8 @@ public class DeleteDraftPatchSet implements RestModifyView<RevisionResource, Inp
     }
 
     private void deleteOrUpdateDraftChange(ChangeContext ctx)
-        throws OrmException, RestApiException {
+        throws OrmException, RestApiException, IOException,
+        NoSuchChangeException {
       Change c = ctx.getChange();
       if (deletedOnlyPatchSet()) {
         deleteChangeOp = deleteChangeOpProvider.get();

gerrit-server/src/main/java/com/google/gerrit/server/index/SchemaUtil.java

@@ -72,6 +72,16 @@ public class SchemaUtil {
     return new Schema<>(ImmutableList.copyOf(fields));
   }
 
+  @SafeVarargs
+  public static <V> Schema<V> schema(Schema<V> schema,
+      FieldDef<V, ?>... moreFields) {
+    return new Schema<>(
+        new ImmutableList.Builder<FieldDef<V, ?>>()
+            .addAll(schema.getFields().values())
+            .addAll(ImmutableList.copyOf(moreFields))
+            .build());
+  }
+
   @SafeVarargs
   public static <V> Schema<V> schema(FieldDef<V, ?>... fields) {
     return schema(ImmutableList.copyOf(fields));

gerrit-server/src/main/java/com/google/gerrit/server/index/change/ChangeField.java

@@ -576,6 +576,23 @@ public class ChangeField {
         }
       };
 
+  /** Users who have starred this change. */
+  public static final FieldDef<ChangeData, Iterable<Integer>> STARREDBY =
+      new FieldDef.Repeatable<ChangeData, Integer>(
+          ChangeQueryBuilder.FIELD_STARREDBY, FieldType.INTEGER, true) {
+        @Override
+        public Iterable<Integer> get(ChangeData input, FillArgs args)
+            throws OrmException {
+          return Iterables.transform(input.starredBy(),
+              new Function<Account.Id, Integer>() {
+            @Override
+            public Integer apply(Account.Id accountId) {
+              return accountId.get();
+            }
+          });
+        }
+      };
+
   /** Opaque group identifiers for this change's patch sets. */
   public static final FieldDef<ChangeData, Iterable<String>> GROUP =
       new FieldDef.Repeatable<ChangeData, String>(

gerrit-server/src/main/java/com/google/gerrit/server/index/change/ChangeIndexer.java

@@ -186,13 +186,25 @@ public class ChangeIndexer {
   /**
    * Synchronously index a change.
    *
-   * @param change change to index.
    * @param db review database.
+   * @param change change to index.
    */
   public void index(ReviewDb db, Change change) throws IOException {
     index(changeDataFactory.create(db, change));
   }
 
+  /**
+   * Synchronously index a change.
+   *
+   * @param db review database.
+   * @param project the project to which the change belongs.
+   * @param changeId ID of the change to index.
+   */
+  public void index(ReviewDb db, Project.NameKey project, Change.Id changeId)
+      throws IOException {
+    index(changeDataFactory.create(db, project, changeId));
+  }
+
   /**
    * Start deleting a change.
    *

gerrit-server/src/main/java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java

@@ -96,8 +96,11 @@ public class ChangeSchemaDefinitions extends SchemaDefinitions<ChangeData> {
       ChangeField.COMMITTER,
       ChangeField.DRAFTBY);
 
+  @Deprecated
   static final Schema<ChangeData> V27 = schema(V26.getFields().values());
 
+  static final Schema<ChangeData> V28 = schema(V27, ChangeField.STARREDBY);
+
   public static final ChangeSchemaDefinitions INSTANCE =
       new ChangeSchemaDefinitions();
 

gerrit-server/src/main/java/com/google/gerrit/server/mail/ChangeEmail.java

@@ -33,6 +33,7 @@ import com.google.gerrit.server.patch.PatchList;
 import com.google.gerrit.server.patch.PatchListEntry;
 import com.google.gerrit.server.patch.PatchListNotAvailableException;
 import com.google.gerrit.server.patch.PatchSetInfoNotAvailableException;
+import com.google.gerrit.server.project.NoSuchChangeException;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gwtorm.server.OrmException;
@@ -305,10 +306,10 @@ public abstract class ChangeEmail extends NotificationEmail {
       // BCC anyone who has starred this change.
       //
       for (Account.Id accountId : args.starredChangesUtil
-          .byChange(change.getId())) {
+          .byChangeFromIndex(change.getId())) {
         super.add(RecipientType.BCC, accountId);
       }
-    } catch (OrmException err) {
+    } catch (OrmException | NoSuchChangeException err) {
       // Just don't BCC everyone. Better to send a partial message to those
       // we already have queued up then to fail deliver entirely to people
       // who have a lower interest in the change.

gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeData.java

@@ -44,6 +44,7 @@ import com.google.gerrit.server.CurrentUser;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.PatchLineCommentsUtil;
 import com.google.gerrit.server.PatchSetUtil;
+import com.google.gerrit.server.StarredChangesUtil;
 import com.google.gerrit.server.change.MergeabilityCache;
 import com.google.gerrit.server.git.GitRepositoryManager;
 import com.google.gerrit.server.git.MergeUtil;
@@ -296,7 +297,7 @@ public class ChangeData {
   public static ChangeData createForTest(Project.NameKey project, Change.Id id,
       int currentPatchSetId) {
     ChangeData cd = new ChangeData(null, null, null, null, null, null, null,
-        null, null, null, null, null, null, null, project, id);
+        null, null, null, null, null, null, null, null, project, id);
     cd.currentPatchSet = new PatchSet(new PatchSet.Id(id, currentPatchSetId));
     return cd;
   }
@@ -315,6 +316,7 @@ public class ChangeData {
   private final PatchListCache patchListCache;
   private final NotesMigration notesMigration;
   private final MergeabilityCache mergeabilityCache;
+  private final StarredChangesUtil starredChangesUtil;
   private final Change.Id legacyId;
   private DataSource<ChangeData> returnedBySource;
   private Project.NameKey project;
@@ -338,6 +340,7 @@ public class ChangeData {
   private Set<Account.Id> editsByUser;
   private Set<Account.Id> reviewedBy;
   private Set<Account.Id> draftsByUser;
+  private Set<Account.Id> starredByUser;
   private PersonIdent author;
   private PersonIdent committer;
 
@@ -356,6 +359,7 @@ public class ChangeData {
       PatchListCache patchListCache,
       NotesMigration notesMigration,
       MergeabilityCache mergeabilityCache,
+      StarredChangesUtil starredChangesUtil,
       @Assisted ReviewDb db,
       @Assisted Project.NameKey project,
       @Assisted Change.Id id) {
@@ -373,6 +377,7 @@ public class ChangeData {
     this.patchListCache = patchListCache;
     this.notesMigration = notesMigration;
     this.mergeabilityCache = mergeabilityCache;
+    this.starredChangesUtil = starredChangesUtil;
     this.project = project;
     this.legacyId = id;
   }
@@ -392,6 +397,7 @@ public class ChangeData {
       PatchListCache patchListCache,
       NotesMigration notesMigration,
       MergeabilityCache mergeabilityCache,
+      StarredChangesUtil starredChangesUtil,
       @Assisted ReviewDb db,
       @Assisted Change c) {
     this.db = db;
@@ -408,6 +414,7 @@ public class ChangeData {
     this.patchListCache = patchListCache;
     this.notesMigration = notesMigration;
     this.mergeabilityCache = mergeabilityCache;
+    this.starredChangesUtil = starredChangesUtil;
     legacyId = c.getId();
     change = c;
     project = c.getProject();
@@ -428,6 +435,7 @@ public class ChangeData {
       PatchListCache patchListCache,
       NotesMigration notesMigration,
       MergeabilityCache mergeabilityCache,
+      StarredChangesUtil starredChangesUtil,
       @Assisted ReviewDb db,
       @Assisted ChangeNotes cn) {
     this.db = db;
@@ -444,6 +452,7 @@ public class ChangeData {
     this.patchListCache = patchListCache;
     this.notesMigration = notesMigration;
     this.mergeabilityCache = mergeabilityCache;
+    this.starredChangesUtil = starredChangesUtil;
     legacyId = cn.getChangeId();
     change = cn.getChange();
     project = cn.getProjectName();
@@ -465,6 +474,7 @@ public class ChangeData {
       PatchListCache patchListCache,
       NotesMigration notesMigration,
       MergeabilityCache mergeabilityCache,
+      StarredChangesUtil starredChangesUtil,
       @Assisted ReviewDb db,
       @Assisted ChangeControl c) {
     this.db = db;
@@ -481,6 +491,7 @@ public class ChangeData {
     this.patchListCache = patchListCache;
     this.notesMigration = notesMigration;
     this.mergeabilityCache = mergeabilityCache;
+    this.starredChangesUtil = starredChangesUtil;
     legacyId = c.getId();
     change = c.getChange();
     changeControl = c;
@@ -503,6 +514,7 @@ public class ChangeData {
       PatchListCache patchListCache,
       NotesMigration notesMigration,
       MergeabilityCache mergeabilityCache,
+      StarredChangesUtil starredChangesUtil,
       @Assisted ReviewDb db,
       @Assisted Change.Id id) {
     checkState(!notesMigration.readChanges(),
@@ -521,6 +533,7 @@ public class ChangeData {
     this.patchListCache = patchListCache;
     this.notesMigration = notesMigration;
     this.mergeabilityCache = mergeabilityCache;
+    this.starredChangesUtil = starredChangesUtil;
     this.legacyId = id;
     this.project = null;
   }
@@ -1005,6 +1018,17 @@ public class ChangeData {
     this.reviewedBy = reviewedBy;
   }
 
+  public Set<Account.Id> starredBy() throws OrmException {
+    if (starredByUser == null) {
+      starredByUser = starredChangesUtil.byChange(legacyId);
+    }
+    return starredByUser;
+  }
+
+  public void setStarredBy(Set<Account.Id> starredByUser) {
+    this.starredByUser = starredByUser;
+  }
+
   @AutoValue
   abstract static class ReviewedByEvent {
     private static ReviewedByEvent create(ChangeMessage msg) {

gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java

@@ -419,7 +419,7 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   @Operator
   public Predicate<ChangeData> has(String value) throws QueryParseException {
     if ("star".equalsIgnoreCase(value)) {
-      return new IsStarredByPredicate(args);
+      return starredby(self());
     }
 
     if ("draft".equalsIgnoreCase(value)) {
@@ -435,7 +435,7 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   @Operator
   public Predicate<ChangeData> is(String value) throws QueryParseException {
     if ("starred".equalsIgnoreCase(value)) {
-      return new IsStarredByPredicate(args);
+      return starredby(self());
     }
 
     if ("watched".equalsIgnoreCase(value)) {
@@ -648,17 +648,25 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   @Operator
   public Predicate<ChangeData> starredby(String who)
       throws QueryParseException, OrmException {
-    if ("self".equals(who)) {
+    return starredby(parseAccount(who));
-      return new IsStarredByPredicate(args);
   }
-    Set<Account.Id> m = parseAccount(who);
+
-    List<IsStarredByPredicate> p = Lists.newArrayListWithCapacity(m.size());
+  private Predicate<ChangeData> starredby(Set<Account.Id> who)
-    for (Account.Id id : m) {
+      throws QueryParseException {
-      p.add(new IsStarredByPredicate(args.asUser(id)));
+    List<Predicate<ChangeData>> p = Lists.newArrayListWithCapacity(who.size());
+    for (Account.Id id : who) {
+      p.add(starredby(id));
     }
     return Predicate.or(p);
   }
 
+  private Predicate<ChangeData> starredby(Account.Id who)
+      throws QueryParseException {
+    return args.getSchema().hasField(ChangeField.STARREDBY)
+        ? new IsStarredByPredicate(who)
+        : new IsStarredByLegacyPredicate(args.asUser(who));
+  }
+
   @Operator
   public Predicate<ChangeData> watchedby(String who)
       throws QueryParseException, OrmException {

gerrit-server/src/main/java/com/google/gerrit/server/query/change/InternalChangeQuery.java

@@ -28,6 +28,7 @@ import com.google.common.collect.ImmutableSet;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.google.gerrit.common.Nullable;
+import com.google.gerrit.reviewdb.client.Account;
 import com.google.gerrit.reviewdb.client.Branch;
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.Project;
@@ -297,6 +298,10 @@ public class InternalChangeQuery {
     return query(and(project(project), or(groupPredicates)));
   }
 
+  public List<ChangeData> byIsStarred(Account.Id id) throws OrmException {
+    return query(new IsStarredByPredicate(id));
+  }
+
   public List<ChangeData> query(Predicate<ChangeData> p) throws OrmException {
     try {
       return qp.queryChanges(p).changes();

gerrit-server/src/main/java/com/google/gerrit/server/query/change/IsStarredByLegacyPredicate.java

@@ -0,0 +1,71 @@
+// Copyright (C) 2010 The Android Open Source Project
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+// http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package com.google.gerrit.server.query.change;
+
+import com.google.common.collect.Lists;
+import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.query.OrPredicate;
+import com.google.gerrit.server.query.Predicate;
+import com.google.gerrit.server.query.QueryParseException;
+import com.google.gerrit.server.query.change.ChangeQueryBuilder.Arguments;
+
+import java.util.List;
+import java.util.Set;
+
+@Deprecated
+class IsStarredByLegacyPredicate extends OrPredicate<ChangeData> {
+  private static String describe(CurrentUser user) {
+    if (user.isIdentifiedUser()) {
+      return user.getAccountId().toString();
+    }
+    return user.toString();
+  }
+
+  private static List<Predicate<ChangeData>> predicates(Set<Change.Id> ids) {
+    List<Predicate<ChangeData>> r = Lists.newArrayListWithCapacity(ids.size());
+    for (Change.Id id : ids) {
+      r.add(new LegacyChangeIdPredicate(id));
+    }
+    return r;
+  }
+
+  private final CurrentUser user;
+
+  IsStarredByLegacyPredicate(Arguments args) throws QueryParseException {
+    super(predicates(args.getIdentifiedUser().getStarredChanges()));
+    this.user = args.getIdentifiedUser();
+  }
+
+  @Override
+  public boolean match(final ChangeData object) {
+    return user.getStarredChanges().contains(object.getId());
+  }
+
+  @Override
+  public int getCost() {
+    return 0;
+  }
+
+  @Override
+  public String toString() {
+    String val = describe(user);
+    if (val.indexOf(' ') < 0) {
+      return ChangeQueryBuilder.FIELD_STARREDBY + ":" + val;
+    } else {
+      return ChangeQueryBuilder.FIELD_STARREDBY + ":\"" + val + "\"";
+    }
+  }
+}

gerrit-server/src/main/java/com/google/gerrit/server/query/change/IsStarredByPredicate.java

@@ -14,57 +14,31 @@
 
 package com.google.gerrit.server.query.change;
 
-import com.google.common.collect.Lists;
+import com.google.gerrit.reviewdb.client.Account;
-import com.google.gerrit.reviewdb.client.Change;
+import com.google.gerrit.server.index.IndexPredicate;
-import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.index.change.ChangeField;
-import com.google.gerrit.server.query.OrPredicate;
+import com.google.gwtorm.server.OrmException;
-import com.google.gerrit.server.query.Predicate;
-import com.google.gerrit.server.query.QueryParseException;
-import com.google.gerrit.server.query.change.ChangeQueryBuilder.Arguments;
 
-import java.util.List;
+class IsStarredByPredicate extends IndexPredicate<ChangeData> {
-import java.util.Set;
+  private final Account.Id accountId;
 
-class IsStarredByPredicate extends OrPredicate<ChangeData> {
+  IsStarredByPredicate(Account.Id accountId) {
-  private static String describe(CurrentUser user) {
+    super(ChangeField.STARREDBY, accountId.toString());
-    if (user.isIdentifiedUser()) {
+    this.accountId = accountId;
-      return user.getAccountId().toString();
-    }
-    return user.toString();
-  }
-
-  private static List<Predicate<ChangeData>> predicates(Set<Change.Id> ids) {
-    List<Predicate<ChangeData>> r = Lists.newArrayListWithCapacity(ids.size());
-    for (Change.Id id : ids) {
-      r.add(new LegacyChangeIdPredicate(id));
-    }
-    return r;
-  }
-
-  private final CurrentUser user;
-
-  IsStarredByPredicate(Arguments args) throws QueryParseException {
-    super(predicates(args.getIdentifiedUser().getStarredChanges()));
-    this.user = args.getIdentifiedUser();
   }
 
   @Override
-  public boolean match(final ChangeData object) {
+  public boolean match(ChangeData cd) throws OrmException {
-    return user.getStarredChanges().contains(object.getId());
+    return cd.starredBy().contains(accountId);
   }
 
   @Override
   public int getCost() {
-    return 0;
+    return 1;
   }
 
   @Override
   public String toString() {
-    String val = describe(user);
+    return ChangeQueryBuilder.FIELD_STARREDBY + ":" + accountId;
-    if (val.indexOf(' ') < 0) {
-      return ChangeQueryBuilder.FIELD_STARREDBY + ":" + val;
-    } else {
-      return ChangeQueryBuilder.FIELD_STARREDBY + ":\"" + val + "\"";
-    }
   }
 }

gerrit-server/src/test/java/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java

@@ -1172,6 +1172,23 @@ public abstract class AbstractQueryChangesTest extends GerritServerTests {
     assertQuery("draftby:" + user2);
   }
 
+  @Test
+  public void byStarredBy() throws Exception {
+    TestRepository<Repo> repo = createProject("repo");
+    Change change1 = insert(repo, newChange(repo));
+    Change change2 = insert(repo, newChange(repo));
+    insert(repo, newChange(repo));
+
+    gApi.accounts().self().starChange(change1.getId().toString());
+    gApi.accounts().self().starChange(change2.getId().toString());
+
+    int user2 = accountManager.authenticate(AuthRequest.forUser("anotheruser"))
+        .getAccountId().get();
+
+    assertQuery("starredby:self", change2, change1);
+    assertQuery("starredby:" + user2);
+  }
+
   @Test
   public void byFrom() throws Exception {
     TestRepository<Repo> repo = createProject("repo");