diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountResolver.java b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountResolver.java
index e738c6f..3dce94e 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountResolver.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/account/AccountResolver.java
@@ -15,12 +15,14 @@
 package com.google.gerrit.server.account;
 
 import com.google.gerrit.reviewdb.Account;
+import com.google.gerrit.reviewdb.AccountExternalId;
 import com.google.gerrit.reviewdb.ReviewDb;
 import com.google.gwtorm.client.OrmException;
-import com.google.gwtorm.client.ResultSet;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
 
+import java.util.Collections;
+import java.util.HashSet;
 import java.util.List;
 import java.util.Set;
 import java.util.regex.Matcher;
@@ -52,28 +54,37 @@
    *         there are multiple candidates.
    */
   public Account find(final String nameOrEmail) throws OrmException {
+    Set<Account.Id> r = findAll(nameOrEmail);
+    return r.size() == 1 ? byId.get(r.iterator().next()).getAccount() : null;
+  }
+
+  /**
+   * Locate exactly one account matching the name or name/email string.
+   *
+   * @param nameOrEmail a string of the format
+   *        "Full Name &lt;email@example&gt;", just the email address
+   *        ("email@example"), a full name ("Full Name"), an account id
+   *        ("18419") or an user name ("username").
+   * @return the accounts that match, empty collection if none.  Never null.
+   */
+  public Set<Account.Id> findAll(String nameOrEmail) throws OrmException {
     Matcher m = Pattern.compile("^.* \\(([1-9][0-9]*)\\)$").matcher(nameOrEmail);
     if (m.matches()) {
-      return byId.get(Account.Id.parse(m.group(1))).getAccount();
+      return Collections.singleton(Account.Id.parse(m.group(1)));
     }
 
     if (nameOrEmail.matches("^[1-9][0-9]*$")) {
-      return byId.get(Account.Id.parse(nameOrEmail)).getAccount();
+      return Collections.singleton(Account.Id.parse(nameOrEmail));
     }
 
     if (nameOrEmail.matches(Account.USER_NAME_PATTERN)) {
-      Account who = findByUserName(nameOrEmail);
+      AccountState who = byId.getByUsername(nameOrEmail);
       if (who != null) {
-        return who;
+        return Collections.singleton(who.getAccount().getId());
       }
     }
 
-    Account account = findByNameOrEmail(nameOrEmail);
-    if (account != null) {
-      return account;
-    }
-
-    return null;
+    return findAllByNameOrEmail(nameOrEmail);
   }
 
   /**
@@ -87,39 +98,61 @@
    */
   public Account findByNameOrEmail(final String nameOrEmail)
       throws OrmException {
+    Set<Account.Id> r = findAllByNameOrEmail(nameOrEmail);
+    return r.size() == 1 ? byId.get(r.iterator().next()).getAccount() : null;
+  }
+
+  /**
+   * Locate exactly one account matching the name or name/email string.
+   *
+   * @param nameOrEmail a string of the format
+   *        "Full Name &lt;email@example&gt;", just the email address
+   *        ("email@example"), a full name ("Full Name").
+   * @return the accounts that match, empty collection if none. Never null.
+   */
+  public Set<Account.Id> findAllByNameOrEmail(final String nameOrEmail)
+      throws OrmException {
     final int lt = nameOrEmail.indexOf('<');
     final int gt = nameOrEmail.indexOf('>');
     if (lt >= 0 && gt > lt && nameOrEmail.contains("@")) {
-      return findByEmail(nameOrEmail.substring(lt + 1, gt));
+      return byEmail.get(nameOrEmail.substring(lt + 1, gt));
     }
 
     if (nameOrEmail.contains("@")) {
-      return findByEmail(nameOrEmail);
+      return byEmail.get(nameOrEmail);
     }
 
     final Account.Id id = realm.lookup(nameOrEmail);
     if (id != null) {
-      return byId.get(id).getAccount();
+      return Collections.singleton(id);
     }
 
-    return oneAccount(schema.get().accounts().byFullName(nameOrEmail));
-  }
-
-  private Account findByEmail(final String email) {
-    final Set<Account.Id> candidates = byEmail.get(email);
-    if (1 == candidates.size()) {
-      return byId.get(candidates.iterator().next()).getAccount();
+    List<Account> m = schema.get().accounts().byFullName(nameOrEmail).toList();
+    if (m.size() == 1) {
+      return Collections.singleton(m.get(0).getId());
     }
-    return null;
-  }
 
-  private static Account oneAccount(final ResultSet<Account> rs) {
-    final List<Account> r = rs.toList();
-    return r.size() == 1 ? r.get(0) : null;
-  }
-
-  private Account findByUserName(final String userName) {
-    AccountState as = byId.getByUsername(userName);
-    return as != null ? as.getAccount() : null;
+    // At this point we have no clue. Just perform a whole bunch of suggestions
+    // and pray we come up with a reasonable result list.
+    //
+    Set<Account.Id> result = new HashSet<Account.Id>();
+    String a = nameOrEmail;
+    String b = nameOrEmail + "\u9fa5";
+    for (Account act : schema.get().accounts().suggestByFullName(a, b, 10)) {
+      result.add(act.getId());
+    }
+    for (AccountExternalId extId : schema
+        .get()
+        .accountExternalIds()
+        .suggestByKey(
+            new AccountExternalId.Key(AccountExternalId.SCHEME_USERNAME, a),
+            new AccountExternalId.Key(AccountExternalId.SCHEME_USERNAME, b), 10)) {
+      result.add(extId.getAccountId());
+    }
+    for (AccountExternalId extId : schema.get().accountExternalIds()
+        .suggestByEmailAddress(a, b, 10)) {
+      result.add(extId.getAccountId());
+    }
+    return result;
   }
 }
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/query/RewritePredicate.java b/gerrit-server/src/main/java/com/google/gerrit/server/query/RewritePredicate.java
index c0a00ca..35fbc1c 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/RewritePredicate.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/RewritePredicate.java
@@ -20,10 +20,12 @@
 import java.util.List;
 
 public abstract class RewritePredicate<T> extends Predicate<T> {
-  private String name = getClass().getName();
+  private boolean init;
+  private String name = getClass().getSimpleName();
   private List<Predicate<T>> children = Collections.emptyList();
 
-  void init(String name, Predicate<T>[] args) {
+  protected void init(String name, Predicate<T>... args) {
+    this.init = true;
     this.name = name;
     this.children = Arrays.asList(args);
   }
@@ -33,10 +35,18 @@
     return this;
   }
 
+  @SuppressWarnings("unchecked")
   @Override
   public boolean equals(Object other) {
-    return getClass() == other.getClass()
-        && children.equals(((RewritePredicate) other).children);
+    if (other instanceof RewritePredicate) {
+      RewritePredicate that = (RewritePredicate<T>) other;
+      if (this.init && that.init) {
+        return this.getClass() == that.getClass()
+            && this.name.equals(that.name)
+            && this.children.equals(that.children);
+      }
+    }
+    return this == other;
   }
 
   @Override
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
index 828a126..eccb2e8 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java
@@ -40,8 +40,11 @@
 
 import org.eclipse.jgit.lib.AbbreviatedObjectId;
 
+import java.util.ArrayList;
 import java.util.Collection;
 import java.util.HashSet;
+import java.util.List;
+import java.util.Set;
 import java.util.regex.Pattern;
 
 /**
@@ -346,21 +349,37 @@
   @Operator
   public Predicate<ChangeData> owner(String who) throws QueryParseException,
       OrmException {
-    Account account = args.accountResolver.find(who);
-    if (account == null) {
+    Set<Account.Id> m = args.accountResolver.findAll(who);
+    if (m.isEmpty()) {
       throw error("User " + who + " not found");
+    } else if (m.size() == 1) {
+      Account.Id id = m.iterator().next();
+      return new OwnerPredicate(args.dbProvider, id);
+    } else {
+      List<OwnerPredicate> p = new ArrayList<OwnerPredicate>(m.size());
+      for (Account.Id id : m) {
+        p.add(new OwnerPredicate(args.dbProvider, id));
+      }
+      return Predicate.or(p);
     }
-    return new OwnerPredicate(args.dbProvider, account.getId());
   }
 
   @Operator
-  public Predicate<ChangeData> reviewer(String nameOrEmail)
+  public Predicate<ChangeData> reviewer(String who)
       throws QueryParseException, OrmException {
-    Account account = args.accountResolver.find(nameOrEmail);
-    if (account == null) {
-      throw error("Reviewer " + nameOrEmail + " not found");
+    Set<Account.Id> m = args.accountResolver.findAll(who);
+    if (m.isEmpty()) {
+      throw error("User " + who + " not found");
+    } else if (m.size() == 1) {
+      Account.Id id = m.iterator().next();
+      return new ReviewerPredicate(args.dbProvider, id);
+    } else {
+      List<ReviewerPredicate> p = new ArrayList<ReviewerPredicate>(m.size());
+      for (Account.Id id : m) {
+        p.add(new ReviewerPredicate(args.dbProvider, id));
+      }
+      return Predicate.or(p);
     }
-    return new ReviewerPredicate(args.dbProvider, account.getId());
   }
 
   @Operator
diff --git a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryRewriter.java b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryRewriter.java
index 98b12f7..904bc3c 100644
--- a/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryRewriter.java
+++ b/gerrit-server/src/main/java/com/google/gerrit/server/query/change/ChangeQueryRewriter.java
@@ -38,8 +38,7 @@
               new ChangeQueryBuilder.Arguments( //
                   new InvalidProvider<ReviewDb>(), //
                   new InvalidProvider<ChangeQueryRewriter>(), //
-                  null, null, null, null, null, null, null, null, null),
-              null));
+                  null, null, null, null, null, null, null, null, null), null));
 
   private final Provider<ReviewDb> dbProvider;
 
@@ -287,11 +286,16 @@
     };
   }
 
+  @SuppressWarnings("unchecked")
   @Rewrite("status:merged S=(sortkey_after:*) L=(limit:*)")
   public Predicate<ChangeData> r20_byMergedPrev(
       @Named("S") final SortKeyPredicate.After s,
       @Named("L") final IntPredicate<ChangeData> l) {
     return new PaginatedSource(50000, s.getValue(), l.intValue()) {
+      {
+        init("r20_byMergedPrev", s, l);
+      }
+
       @Override
       ResultSet<Change> scan(ChangeAccess a, String key, int limit)
           throws OrmException {
@@ -306,11 +310,16 @@
     };
   }
 
+  @SuppressWarnings("unchecked")
   @Rewrite("status:merged S=(sortkey_before:*) L=(limit:*)")
   public Predicate<ChangeData> r20_byMergedNext(
       @Named("S") final SortKeyPredicate.Before s,
       @Named("L") final IntPredicate<ChangeData> l) {
     return new PaginatedSource(50000, s.getValue(), l.intValue()) {
+      {
+        init("r20_byMergedNext", s, l);
+      }
+
       @Override
       ResultSet<Change> scan(ChangeAccess a, String key, int limit)
           throws OrmException {
@@ -325,11 +334,16 @@
     };
   }
 
+  @SuppressWarnings("unchecked")
   @Rewrite("status:abandoned S=(sortkey_after:*) L=(limit:*)")
   public Predicate<ChangeData> r20_byAbandonedPrev(
       @Named("S") final SortKeyPredicate.After s,
       @Named("L") final IntPredicate<ChangeData> l) {
     return new PaginatedSource(50000, s.getValue(), l.intValue()) {
+      {
+        init("r20_byAbandonedPrev", s, l);
+      }
+
       @Override
       ResultSet<Change> scan(ChangeAccess a, String key, int limit)
           throws OrmException {
@@ -344,11 +358,16 @@
     };
   }
 
+  @SuppressWarnings("unchecked")
   @Rewrite("status:abandoned S=(sortkey_before:*) L=(limit:*)")
   public Predicate<ChangeData> r20_byAbandonedNext(
       @Named("S") final SortKeyPredicate.Before s,
       @Named("L") final IntPredicate<ChangeData> l) {
     return new PaginatedSource(50000, s.getValue(), l.intValue()) {
+      {
+        init("r20_byAbandonedNext", s, l);
+      }
+
       @Override
       ResultSet<Change> scan(ChangeAccess a, String key, int limit)
           throws OrmException {
@@ -379,10 +398,15 @@
     return or(r20_byMergedNext(s, l), r20_byAbandonedNext(s, l));
   }
 
+  @SuppressWarnings("unchecked")
   @Rewrite("status:open O=(owner:*)")
   public Predicate<ChangeData> r25_byOwnerOpen(
       @Named("O") final OwnerPredicate o) {
     return new ChangeSource(50) {
+      {
+        init("r25_byOwnerOpen", o);
+      }
+
       @Override
       ResultSet<Change> scan(ChangeAccess a) throws OrmException {
         return a.byOwnerOpen(o.getAccountId());
@@ -395,10 +419,15 @@
     };
   }
 
+  @SuppressWarnings("unchecked")
   @Rewrite("status:closed O=(owner:*)")
   public Predicate<ChangeData> r25_byOwnerClosed(
       @Named("O") final OwnerPredicate o) {
     return new ChangeSource(5000) {
+      {
+        init("r25_byOwnerClosed", o);
+      }
+
       @Override
       ResultSet<Change> scan(ChangeAccess a) throws OrmException {
         return a.byOwnerClosedAll(o.getAccountId());
@@ -417,10 +446,15 @@
     return or(r25_byOwnerOpen(o), r25_byOwnerClosed(o));
   }
 
+  @SuppressWarnings("unchecked")
   @Rewrite("status:open R=(reviewer:*)")
   public Predicate<ChangeData> r30_byReviewerOpen(
       @Named("R") final ReviewerPredicate r) {
     return new Source() {
+      {
+        init("r30_byReviewerOpen", r);
+      }
+
       @Override
       public ResultSet<ChangeData> read() throws OrmException {
         return ChangeDataResultSet.patchSetApproval(dbProvider.get()
@@ -445,10 +479,15 @@
     };
   }
 
+  @SuppressWarnings("unchecked")
   @Rewrite("status:closed R=(reviewer:*)")
   public Predicate<ChangeData> r30_byReviewerClosed(
       @Named("R") final ReviewerPredicate r) {
     return new Source() {
+      {
+        init("r30_byReviewerClosed", r);
+      }
+
       @Override
       public ResultSet<ChangeData> read() throws OrmException {
         return ChangeDataResultSet.patchSetApproval(dbProvider.get()