Merge changes from topics 'query-refactor', 'kill-sortkey'

* changes:
  QueryProcessor: Don't double-add visibleto predicate
  Add query tests for visibleto predicate
  Terminate sortkey with prejudice
  Use secondary index for advertising extra haves during push
  OutputStreamQuery: Optimize formatter allocation
  Move stream-based QueryProcessor output to its own class
  Add QueryProcessor methods to search by Predicate
  Fix limit handling in QueryProcessor
  QueryChanges: Remove unused reverse field

Documentation/cmd-query.txt

@@ -116,7 +116,7 @@ Find the 2 most recent open changes in the tools/gerrit project:
 ====
   $ ssh -p 29418 review.example.com gerrit query --format=JSON status:open project:tools/gerrit limit:2
   {"project":"tools/gerrit", ...}
-  {"project":"tools/gerrit", ..., sortKey:"000e6aee00003e26", ...}
+  {"project":"tools/gerrit", ...}
   {"type":"stats","rowCount":2,"runningTimeMilliseconds:15}
 ====
 

Documentation/json.txt

@@ -35,8 +35,6 @@ was created.
 lastUpdated:: Time in seconds since the UNIX epoch when this change
 was last updated.
 
-sortKey:: Internal key used to sort changes, based on lastUpdated.
-
 open:: Boolean indicating if the change is still open for review.
 
 status:: Current state of this change.

Documentation/rest-api-accounts.txt

@@ -1123,7 +1123,6 @@ link:rest-api-changes.html#change-info[ChangeInfo] entities.
       "created": "2013-02-01 09:59:32.126000000",
       "updated": "2013-02-21 11:16:36.775000000",
       "mergeable": true,
-      "_sortkey": "0023412400000f7d",
       "_number": 3965,
       "owner": {
         "name": "John Doe"

Documentation/rest-api-changes.txt

@@ -55,7 +55,6 @@ the resulting change.
     "mergeable": true,
     "insertions": 0,
     "deletions": 0,
-    "_sortkey": "002cbc25000004e5",
     "_number": 4711,
     "owner": {
       "name": "John Doe"
@@ -105,7 +104,6 @@ Query for open changes of watched projects:
       "mergeable": true,
       "insertions": 26,
       "deletions": 10,
-      "_sortkey": "001e7057000006dc",
       "_number": 1756,
       "owner": {
         "name": "John Doe"
@@ -123,7 +121,6 @@ Query for open changes of watched projects:
       "mergeable": true,
       "insertions": 12,
       "deletions": 18,
-      "_sortkey": "001e7056000006dd",
       "_number": 1757,
       "owner": {
         "name": "John Doe"
@@ -177,7 +174,6 @@ Query that retrieves changes for a user's dashboard:
         "mergeable": true,
         "insertions": 4,
         "deletions": 7,
-        "_sortkey": "001e7057000006dc",
         "_number": 1756,
         "owner": {
           "name": "John Doe"
@@ -330,7 +326,6 @@ default. Optional fields are:
       "mergeable": true,
       "insertions": 16,
       "deletions": 7,
-      "_sortkey": "001c9bf400000061",
       "_number": 97,
       "owner": {
         "name": "Shawn Pearce"
@@ -467,7 +462,6 @@ describes the change.
     "mergeable": true,
     "insertions": 34,
     "deletions": 101,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -520,7 +514,6 @@ REJECTED > APPROVED > DISLIKED > RECOMMENDED.
     "mergeable": true,
     "insertions": 126,
     "deletions": 11,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "_account_id": 1000096,
@@ -764,7 +757,6 @@ describes the abandoned change.
     "mergeable": true,
     "insertions": 3,
     "deletions": 310,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -823,7 +815,6 @@ describes the restored change.
     "mergeable": true,
     "insertions": 2,
     "deletions": 13,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -880,7 +871,6 @@ is included.
     "mergeable": false,
     "insertions": 33,
     "deletions": 9,
-    "_sortkey": "0024cf9a000012bf",
     "_number": 4799,
     "owner": {
       "name": "John Doe"
@@ -973,7 +963,6 @@ describes the reverting change.
     "mergeable": true,
     "insertions": 6,
     "deletions": 4,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -1035,7 +1024,6 @@ describes the submitted/merged change.
     "status": "MERGED",
     "created": "2013-02-01 09:59:32.126000000",
     "updated": "2013-02-21 11:16:36.775000000",
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -1179,7 +1167,6 @@ missing from the result. At least `id`, `project`, `branch`, and
     "mergeable": true,
     "insertions": 34,
     "deletions": 101,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -1228,7 +1215,6 @@ Only the change owner, a project owner, or an administrator may fix changes.
     "mergeable": true,
     "insertions": 34,
     "deletions": 101,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -1863,7 +1849,6 @@ for the current patch set.
     "mergeable": true,
     "insertions": 34,
     "deletions": 45,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "_account_id": 1000096,
@@ -2128,7 +2113,6 @@ is included.
     "mergeable": false,
     "insertions": 21,
     "deletions": 21,
-    "_sortkey": "0024cf9a000012bf",
     "_number": 4799,
     "owner": {
       "name": "John Doe"
@@ -3096,7 +3080,6 @@ describes the resulting cherry picked change.
     "mergeable": true,
     "insertions": 12,
     "deletions": 11,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -3150,7 +3133,6 @@ describes the change.
     "mergeable": true,
     "insertions": 261,
     "deletions": 101,
-    "_sortkey": "0023412400000f7d",
     "_number": 3965,
     "owner": {
       "name": "John Doe"
@@ -3335,7 +3317,6 @@ Not set for merged changes, or if the change has not yet been tested.
 Number of inserted lines.
 |`deletions`          ||
 Number of deleted lines.
-|`_sortkey`           ||The sortkey of the change.
 |`_number`            ||The legacy numeric ID of the change.
 |`owner`              ||
 The owner of the change as an link:rest-api-accounts.html#account-info[
@@ -3373,7 +3354,7 @@ Only set if link:#current-revision[the current revision] is requested
 if link:#all-revisions[all revisions] are requested.
 |`_more_changes`      |optional, not set if `false`|
 Whether the query would deliver more results if not limited. +
-Only set on either the last or the first change that is returned.
+Only set on the last change that is returned.
 |`problems`           |optional|
 A list of link:#problem-info[ProblemInfo] entities describing potential
 problems with this change. Only set if link:#check[CHECK] is set.

gerrit-common/src/main/java/com/google/gerrit/common/data/ChangeInfo.java

@@ -31,7 +31,6 @@ public class ChangeInfo {
   protected String topic;
   protected boolean starred;
   protected Timestamp lastUpdatedOn;
-  protected String sortKey;
   protected PatchSet.Id patchSetId;
   protected boolean latest;
 
@@ -52,7 +51,6 @@ public class ChangeInfo {
     branch = c.getDest().getShortName();
     topic = c.getTopic();
     lastUpdatedOn = c.getLastUpdatedOn();
-    sortKey = c.getSortKey();
     patchSetId = patchId;
     latest = patchSetId == null || patchSetId.equals(c.currentPatchSetId());
   }
@@ -112,8 +110,4 @@ public class ChangeInfo {
   public java.sql.Timestamp getLastUpdatedOn() {
     return lastUpdatedOn;
   }
-
-  public String getSortKey() {
-    return sortKey;
-  }
 }

gerrit-extension-api/src/main/java/com/google/gerrit/extensions/common/ChangeInfo.java

@@ -36,7 +36,6 @@ public class ChangeInfo {
   public Integer insertions;
   public Integer deletions;
 
-  public String _sortkey;
   public String baseChange;
   public int _number;
 

gerrit-gwtui/src/main/java/com/google/gerrit/client/changes/ChangeInfo.java

@@ -96,7 +96,6 @@ public class ChangeInfo extends JavaScriptObject {
   private final native String updatedRaw() /*-{ return this.updated; }-*/;
   public final native boolean starred() /*-{ return this.starred ? true : false; }-*/;
   public final native boolean reviewed() /*-{ return this.reviewed ? true : false; }-*/;
-  public final native String _sortkey() /*-{ return this._sortkey; }-*/;
   public final native NativeMap<LabelInfo> all_labels() /*-{ return this.labels; }-*/;
   public final native LabelInfo label(String n) /*-{ return this.labels[n]; }-*/;
   public final native String current_revision() /*-{ return this.current_revision; }-*/;

gerrit-httpd/src/main/java/com/google/gerrit/httpd/rpc/change/DeprecatedChangeQueryServlet.java

@@ -14,8 +14,8 @@
 
 package com.google.gerrit.httpd.rpc.change;
 
-import com.google.gerrit.server.query.change.QueryProcessor;
+import com.google.gerrit.server.query.change.OutputStreamQuery;
-import com.google.gerrit.server.query.change.QueryProcessor.OutputFormat;
+import com.google.gerrit.server.query.change.OutputStreamQuery.OutputFormat;
 import com.google.gson.Gson;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -31,11 +31,11 @@ import javax.servlet.http.HttpServletResponse;
 @Singleton
 public class DeprecatedChangeQueryServlet extends HttpServlet {
   private static final long serialVersionUID = 1L;
-  private final Provider<QueryProcessor> processor;
+  private final Provider<OutputStreamQuery> queryProvider;
 
   @Inject
-  DeprecatedChangeQueryServlet(Provider<QueryProcessor> processor) {
+  DeprecatedChangeQueryServlet(Provider<OutputStreamQuery> queryProvider) {
-    this.processor = processor;
+    this.queryProvider = queryProvider;
   }
 
   @Override
@@ -44,7 +44,7 @@ public class DeprecatedChangeQueryServlet extends HttpServlet {
     rsp.setContentType("text/json");
     rsp.setCharacterEncoding("UTF-8");
 
-    QueryProcessor p = processor.get();
+    OutputStreamQuery p = queryProvider.get();
     OutputFormat format = OutputFormat.JSON;
     try {
       format = OutputFormat.valueOf(get(req, "format", format.toString()));

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/client/Change.java

@@ -433,9 +433,7 @@ public final class Change {
   @Column(id = 5)
   protected Timestamp lastUpdatedOn;
 
-  /** A {@link #lastUpdatedOn} ASC,{@link #changeId} ASC for sorting. */
+  // DELETED: id = 6 (sortkey)
-  @Column(id = 6, length = 16)
-  protected String sortKey;
 
   @Column(id = 7, name = "owner_account_id")
   protected Account.Id owner;
@@ -489,7 +487,6 @@ public final class Change {
     rowVersion = other.rowVersion;
     createdOn = other.createdOn;
     lastUpdatedOn = other.lastUpdatedOn;
-    sortKey = other.sortKey;
     owner = other.owner;
     dest = other.dest;
     open = other.open;
@@ -534,14 +531,6 @@ public final class Change {
     return rowVersion;
   }
 
-  public String getSortKey() {
-    return sortKey;
-  }
-
-  public void setSortKey(final String newSortKey) {
-    sortKey = newSortKey;
-  }
-
   public Account.Id getOwner() {
     return owner;
   }

gerrit-reviewdb/src/main/java/com/google/gerrit/reviewdb/server/ChangeAccess.java

@@ -55,11 +55,6 @@ public interface ChangeAccess extends Access<Change, Change.Id> {
   @Query("WHERE open = true AND dest = ?")
   ResultSet<Change> byBranchOpenAll(Branch.NameKey p) throws OrmException;
 
-  @Query("WHERE open = true AND dest.projectName = ? AND sortKey < ?"
-      + " ORDER BY sortKey DESC LIMIT ?")
-  ResultSet<Change> byProjectOpenNext(Project.NameKey p, String sortKey,
-      int limit) throws OrmException;
-
   @Query
   ResultSet<Change> all() throws OrmException;
 }

gerrit-reviewdb/src/main/resources/com/google/gerrit/reviewdb/server/index_generic.sql

@@ -75,7 +75,7 @@ ON changes (status, dest_project_name, dest_branch_name, last_updated_on);
 
 --    covers:             byProjectOpenAll
 CREATE INDEX changes_byProjectOpen
-ON changes (open, dest_project_name, sort_key);
+ON changes (open, dest_project_name, last_updated_on);
 
 --    covers:             byProject
 CREATE INDEX changes_byProject

gerrit-reviewdb/src/main/resources/com/google/gerrit/reviewdb/server/index_maxdb.sql

@@ -83,7 +83,7 @@ ON changes (status, dest_project_name, dest_branch_name, last_updated_on)
 
 --    covers:             byProjectOpenPrev, byProjectOpenNext
 CREATE INDEX changes_byProjectOpen
-ON changes (open, dest_project_name, sort_key)
+ON changes (open, dest_project_name, last_updated_on);
 #
 
 --    covers:             byProject

gerrit-reviewdb/src/main/resources/com/google/gerrit/reviewdb/server/index_postgres.sql

@@ -124,7 +124,7 @@ WHERE status = 's';
 
 --    covers:             byProjectOpenAll
 CREATE INDEX changes_byProjectOpen
-ON changes (dest_project_name, sort_key)
+ON changes (dest_project_name, last_updated_on)
 WHERE open = 'Y';
 
 --    covers:             byProject

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

@@ -15,15 +15,10 @@
 package com.google.gerrit.server;
 
 import static com.google.gerrit.server.change.PatchSetInserter.ValidatePolicy.RECEIVE_COMMITS;
-import static java.util.concurrent.TimeUnit.MILLISECONDS;
-import static java.util.concurrent.TimeUnit.MINUTES;
-import static java.util.concurrent.TimeUnit.SECONDS;
 
-import com.google.common.annotations.VisibleForTesting;
 import com.google.common.base.Optional;
 import com.google.common.base.Strings;
 import com.google.common.collect.ImmutableList;
-import com.google.common.primitives.Ints;
 import com.google.gerrit.common.TimeUtil;
 import com.google.gerrit.extensions.restapi.ResourceNotFoundException;
 import com.google.gerrit.reviewdb.client.Change;
@@ -85,15 +80,6 @@ import java.util.Map;
 
 @Singleton
 public class ChangeUtil {
-  /**
-   * Epoch for sort key calculations, Tue Sep 30 2008 17:00:00.
-   * <p>
-   * We overrun approximately 4,083 years later, so ~6092.
-   */
-  @VisibleForTesting
-  private static final long SORT_KEY_EPOCH_MINS =
-      MINUTES.convert(1222819200L, SECONDS);
-
   private static final Object uuidLock = new Object();
   private static final int SEED = 0x2418e6f9;
   private static int uuidPrefix;
@@ -150,7 +136,6 @@ public class ChangeUtil {
 
   public static void updated(Change c) {
     c.setLastUpdatedOn(TimeUtil.nowTs());
-    computeSortKey(c);
   }
 
   public static void insertAncestors(ReviewDb db, PatchSet.Id id, RevCommit src)
@@ -166,29 +151,6 @@ public class ChangeUtil {
     db.patchSetAncestors().insert(toInsert);
   }
 
-  public static String sortKey(long lastUpdatedMs, int id) {
-    long lastUpdatedMins = MINUTES.convert(lastUpdatedMs, MILLISECONDS);
-    long minsSinceEpoch = lastUpdatedMins - SORT_KEY_EPOCH_MINS;
-    StringBuilder r = new StringBuilder(16);
-    r.setLength(16);
-    formatHexInt(r, 0, Ints.checkedCast(minsSinceEpoch));
-    formatHexInt(r, 8, id);
-    return r.toString();
-  }
-
-  public static long parseSortKey(String sortKey) {
-    if ("z".equals(sortKey)) {
-      return Long.MAX_VALUE;
-    }
-    return Long.parseLong(sortKey, 16);
-  }
-
-  public static void computeSortKey(Change c) {
-    long lastUpdatedMs = c.getLastUpdatedOn().getTime();
-    int id = c.getId().get();
-    c.setSortKey(sortKey(lastUpdatedMs, id));
-  }
-
   public static PatchSet.Id nextPatchSetId(Map<String, Ref> allRefs,
       PatchSet.Id id) {
     PatchSet.Id next = nextPatchSetId(id);
@@ -585,19 +547,4 @@ public class ChangeUtil {
   public static PatchSet.Id nextPatchSetId(PatchSet.Id id) {
     return new PatchSet.Id(id.getParentKey(), id.get() + 1);
   }
-
-  private static final char[] hexchar =
-      {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', //
-          'a', 'b', 'c', 'd', 'e', 'f'};
-
-  private static void formatHexInt(final StringBuilder dst, final int p, int w) {
-    int o = p + 7;
-    while (o >= p && w != 0) {
-      dst.setCharAt(o--, hexchar[w & 0xf]);
-      w >>>= 4;
-    }
-    while (o >= p) {
-      dst.setCharAt(o--, '0');
-    }
-  }
 }

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

@@ -136,7 +136,6 @@ public class ChangeInserter {
     patchSet.setRevision(new RevId(commit.name()));
     patchSetInfo = patchSetInfoFactory.get(commit, patchSet.getId());
     change.setCurrentPatchSet(patchSetInfo);
-    ChangeUtil.computeSortKey(change);
   }
 
   public Change getChange() {

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

@@ -104,6 +104,7 @@ import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.project.SubmitRuleEvaluator;
 import com.google.gerrit.server.query.change.ChangeData;
 import com.google.gerrit.server.query.change.ChangeData.ChangedLines;
+import com.google.gerrit.server.query.change.QueryResult;
 import com.google.gwtorm.server.OrmException;
 import com.google.inject.Inject;
 import com.google.inject.Provider;
@@ -252,10 +253,16 @@ public class ChangeJson {
     return format(cd, Optional.of(rsrc.getPatchSet().getId()));
   }
 
-  public List<List<ChangeInfo>> formatList2(List<List<ChangeData>> in)
+  public List<List<ChangeInfo>> formatQueryResults(List<QueryResult> in)
       throws OrmException {
     accountLoader = accountLoaderFactory.create(has(DETAILED_ACCOUNTS));
-    Iterable<ChangeData> all = Iterables.concat(in);
+    Iterable<ChangeData> all = FluentIterable.from(in)
+        .transformAndConcat(new Function<QueryResult, List<ChangeData>>() {
+          @Override
+          public List<ChangeData> apply(QueryResult in) {
+            return in.changes();
+          }
+        });
     ChangeData.ensureChangeLoaded(all);
     if (has(ALL_REVISIONS)) {
       ChangeData.ensureAllPatchSetsLoaded(all);
@@ -270,8 +277,12 @@ public class ChangeJson {
 
     List<List<ChangeInfo>> res = Lists.newArrayListWithCapacity(in.size());
     Map<Change.Id, ChangeInfo> out = Maps.newHashMap();
-    for (List<ChangeData> changes : in) {
+    for (QueryResult r : in) {
-      res.add(toChangeInfo(out, changes, reviewed));
+      List<ChangeInfo> infos = toChangeInfo(out, r.changes(), reviewed);
+      if (r.moreChanges()) {
+        infos.get(infos.size() - 1)._moreChanges = true;
+      }
+      res.add(infos);
     }
     accountLoader.fill();
     return res;
@@ -368,7 +379,6 @@ public class ChangeJson {
     out.created = in.getCreatedOn();
     out.updated = in.getLastUpdatedOn();
     out._number = in.getId().get();
-    out._sortkey = in.getSortKey();
     out.starred = userProvider.get().getStarredChanges().contains(in.getId())
         ? true
         : null;

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

@@ -47,7 +47,6 @@ import com.google.gerrit.reviewdb.client.RevId;
 import com.google.gerrit.reviewdb.server.ReviewDb;
 import com.google.gerrit.server.ApprovalsUtil;
 import com.google.gerrit.server.ChangeMessagesUtil;
-import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.GerritPersonIdent;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.ProjectUtil;
@@ -271,7 +270,6 @@ public class Submit implements RestModifyView<RevisionResource, SubmitInput>,
             if (change.getStatus().isOpen()) {
               change.setStatus(Change.Status.SUBMITTED);
               change.setLastUpdatedOn(timestamp);
-              ChangeUtil.computeSortKey(change);
               return change;
             }
             return null;

gerrit-server/src/main/java/com/google/gerrit/server/data/ChangeAttribute.java

@@ -31,7 +31,6 @@ public class ChangeAttribute {
 
     public Long createdOn;
     public Long lastUpdated;
-    public String sortKey;
     public Boolean open;
     public Change.Status status;
     public List<MessageAttribute> comments;

gerrit-server/src/main/java/com/google/gerrit/server/data/QueryStatsAttribute.java

@@ -18,5 +18,5 @@ public class QueryStatsAttribute {
   public final String type = "stats";
   public int rowCount;
   public long runTimeMilliseconds;
-  public String resumeSortKey;
+  public boolean moreChanges;
 }

gerrit-server/src/main/java/com/google/gerrit/server/events/EventFactory.java

@@ -164,7 +164,6 @@ public class EventFactory {
   public void extend(ChangeAttribute a, Change change) {
     a.createdOn = change.getCreatedOn().getTime() / 1000L;
     a.lastUpdated = change.getLastUpdatedOn().getTime() / 1000L;
-    a.sortKey = change.getSortKey();
     a.open = change.getStatus().isOpen();
   }
 

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

@@ -111,6 +111,7 @@ import com.google.gerrit.server.project.ProjectControl;
 import com.google.gerrit.server.project.ProjectState;
 import com.google.gerrit.server.project.RefControl;
 import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.server.query.change.QueryProcessor;
 import com.google.gerrit.server.ssh.SshInfo;
 import com.google.gerrit.server.util.LabelVote;
 import com.google.gerrit.server.util.MagicBranch;
@@ -336,6 +337,7 @@ public class ReceiveCommits {
 
   @Inject
   ReceiveCommits(final ReviewDb db,
+      final Provider<QueryProcessor> queryProcessor,
       final SchemaFactory<ReviewDb> schemaFactory,
       final ChangeData.Factory changeDataFactory,
       final ChangeUpdate.Factory updateFactory,
@@ -472,7 +474,7 @@ public class ReceiveCommits {
     });
     advHooks.add(rp.getAdvertiseRefsHook());
     advHooks.add(new ReceiveCommitsAdvertiseRefsHook(
-        db, projectControl.getProject().getNameKey()));
+        db, queryProcessor, projectControl.getProject().getNameKey()));
     rp.setAdvertiseRefsHook(AdvertiseRefsHookChain.newChain(advHooks));
   }
 

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

@@ -18,13 +18,18 @@ import static org.eclipse.jgit.lib.RefDatabase.ALL;
 
 import com.google.common.collect.Maps;
 import com.google.common.collect.Sets;
-import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RefNames;
 import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gerrit.server.query.Predicate;
+import com.google.gerrit.server.query.QueryParseException;
+import com.google.gerrit.server.query.change.ChangeData;
+import com.google.gerrit.server.query.change.ChangeQueryBuilder;
+import com.google.gerrit.server.query.change.QueryProcessor;
 import com.google.gerrit.server.util.MagicBranch;
 import com.google.gwtorm.server.OrmException;
+import com.google.inject.Provider;
 
 import org.eclipse.jgit.lib.Constants;
 import org.eclipse.jgit.lib.ObjectId;
@@ -39,6 +44,7 @@ import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
+import java.util.List;
 import java.util.Map;
 import java.util.Set;
 
@@ -48,11 +54,14 @@ public class ReceiveCommitsAdvertiseRefsHook implements AdvertiseRefsHook {
       .getLogger(ReceiveCommitsAdvertiseRefsHook.class);
 
   private final ReviewDb db;
+  private final Provider<QueryProcessor> queryProcessor;
   private final Project.NameKey projectName;
 
   public ReceiveCommitsAdvertiseRefsHook(ReviewDb db,
+      Provider<QueryProcessor> queryProcessor,
       Project.NameKey projectName) {
     this.db = db;
+    this.queryProcessor = queryProcessor;
     this.projectName = projectName;
   }
 
@@ -93,10 +102,11 @@ public class ReceiveCommitsAdvertiseRefsHook implements AdvertiseRefsHook {
     Set<ObjectId> toInclude = Sets.newHashSet();
 
     // Advertise some recent open changes, in case a commit is based one.
+    final int limit = 32;
     try {
-      Set<PatchSet.Id> toGet = Sets.newHashSetWithExpectedSize(32);
+      Set<PatchSet.Id> toGet = Sets.newHashSetWithExpectedSize(limit);
-      for (Change c : db.changes().byProjectOpenNext(projectName, "z", 32)) {
+      for (ChangeData cd : queryRecentChanges(limit)) {
-        PatchSet.Id id = c.currentPatchSetId();
+        PatchSet.Id id = cd.change().currentPatchSetId();
         if (id != null) {
           toGet.add(id);
         }
@@ -164,6 +174,20 @@ public class ReceiveCommitsAdvertiseRefsHook implements AdvertiseRefsHook {
     return toInclude;
   }
 
+  private List<ChangeData> queryRecentChanges(int limit)
+      throws OrmException {
+    QueryProcessor qp = queryProcessor.get();
+    qp.setLimit(limit);
+    ChangeQueryBuilder qb = qp.getQueryBuilder();
+    Predicate<ChangeData> p =
+        Predicate.and(qb.project(projectName.get()), qb.status_open());
+    try {
+      return qp.queryChanges(p).changes();
+    } catch (QueryParseException e) {
+      throw new OrmException(e);
+    }
+  }
+
   private static boolean skip(String name) {
     return name.startsWith(RefNames.REFS_CHANGES)
         || name.startsWith(RefNames.REFS_CACHE_AUTOMERGE)

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

@@ -14,9 +14,8 @@
 
 package com.google.gerrit.server.index;
 
-import static com.google.gerrit.common.data.GlobalCapability.DEFAULT_MAX_QUERY_LIMIT;
+import static com.google.common.base.Preconditions.checkArgument;
 
-import com.google.common.base.MoreObjects;
 import com.google.common.collect.Lists;
 import com.google.common.collect.Sets;
 import com.google.gerrit.reviewdb.client.Change;
@@ -29,9 +28,9 @@ import com.google.gerrit.server.query.QueryParseException;
 import com.google.gerrit.server.query.change.AndSource;
 import com.google.gerrit.server.query.change.BasicChangeRewrites;
 import com.google.gerrit.server.query.change.ChangeData;
-import com.google.gerrit.server.query.change.ChangeQueryBuilder;
 import com.google.gerrit.server.query.change.ChangeQueryRewriter;
 import com.google.gerrit.server.query.change.ChangeStatusPredicate;
+import com.google.gerrit.server.query.change.LimitPredicate;
 import com.google.gerrit.server.query.change.OrSource;
 import com.google.inject.Inject;
 
@@ -129,16 +128,14 @@ public class IndexRewriteImpl implements ChangeQueryRewriter {
   }
 
   @Override
-  public Predicate<ChangeData> rewrite(Predicate<ChangeData> in, int start)
+  public Predicate<ChangeData> rewrite(Predicate<ChangeData> in, int start,
-      throws QueryParseException {
+      int limit) throws QueryParseException {
+    checkArgument(limit > 0, "limit must be positive: %s", limit);
     ChangeIndex index = indexes.getSearchIndex();
     in = basicRewrites.rewrite(in);
-    int limit = MoreObjects.firstNonNull(
-        ChangeQueryBuilder.getLimit(in), DEFAULT_MAX_QUERY_LIMIT);
     // Increase the limit rather than skipping, since we don't know how many
     // skipped results would have been filtered out by the enclosing AndSource.
     limit += start;
-    limit = Math.max(limit, 1);
 
     Predicate<ChangeData> out = rewriteImpl(in, index, limit);
     if (in == out || out instanceof IndexPredicate) {
@@ -168,6 +165,9 @@ public class IndexRewriteImpl implements ChangeQueryRewriter {
       ChangeIndex index, int limit) throws QueryParseException {
     if (isIndexPredicate(in, index)) {
       return in;
+    } else if (in instanceof LimitPredicate) {
+      // Replace any limits with the limit provided by the caller.
+      return new LimitPredicate(limit);
     } else if (!isRewritePossible(in)) {
       return null; // magic to indicate "in" cannot be rewritten
     }

gerrit-server/src/main/java/com/google/gerrit/server/query/QueryBuilder.java

@@ -138,7 +138,8 @@ public abstract class QueryBuilder<T> {
    * @param p the predicate to find.
    * @param clazz type of the predicate instance.
    * @param name name of the operator.
-   * @return the predicate, null if not found.
+   * @return the first instance of a predicate having the given type, as found
+   *     by a depth-first search.
    */
   @SuppressWarnings("unchecked")
   public static <T, P extends OperatorPredicate<T>> P find(Predicate<T> p,

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

@@ -16,13 +16,11 @@ package com.google.gerrit.server.query.change;
 
 import com.google.gerrit.reviewdb.client.Change;
 import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.server.query.IntPredicate;
 import com.google.gerrit.server.query.Predicate;
 import com.google.gerrit.server.query.QueryRewriter;
 import com.google.inject.Inject;
 import com.google.inject.OutOfScopeException;
 import com.google.inject.Provider;
-import com.google.inject.name.Named;
 
 public class BasicChangeRewrites extends QueryRewriter<ChangeData> {
   private static final ChangeQueryBuilder BUILDER = new ChangeQueryBuilder(
@@ -69,14 +67,6 @@ public class BasicChangeRewrites extends QueryRewriter<ChangeData> {
         ChangeStatusPredicate.forStatus(Change.Status.MERGED));
   }
 
-  @NoCostComputation
-  @Rewrite("A=(limit:*) B=(limit:*)")
-  public Predicate<ChangeData> r00_smallestLimit(
-      @Named("A") IntPredicate<ChangeData> a,
-      @Named("B") IntPredicate<ChangeData> b) {
-    return a.intValue() <= b.intValue() ? a : b;
-  }
-
   private static final class InvalidProvider<T> implements Provider<T> {
     @Override
     public T get() {

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

@@ -45,7 +45,6 @@ import com.google.gerrit.server.patch.PatchListCache;
 import com.google.gerrit.server.project.ChangeControl;
 import com.google.gerrit.server.project.ListChildProjects;
 import com.google.gerrit.server.project.ProjectCache;
-import com.google.gerrit.server.query.IntPredicate;
 import com.google.gerrit.server.query.Predicate;
 import com.google.gerrit.server.query.QueryBuilder;
 import com.google.gerrit.server.query.QueryParseException;
@@ -121,12 +120,6 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   private static final QueryBuilder.Definition<ChangeData, ChangeQueryBuilder> mydef =
       new QueryBuilder.Definition<>(ChangeQueryBuilder.class);
 
-  @SuppressWarnings("unchecked")
-  public static Integer getLimit(Predicate<ChangeData> p) {
-    IntPredicate<?> ip = find(p, IntPredicate.class, FIELD_LIMIT);
-    return ip != null ? ip.intValue() : null;
-  }
-
   @VisibleForTesting
   public static class Arguments {
     final Provider<ReviewDb> db;
@@ -633,28 +626,8 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData> {
   }
 
   @Operator
-  public Predicate<ChangeData> limit(String limit) {
+  public Predicate<ChangeData> limit(String limit) throws QueryParseException {
-    return limit(Integer.parseInt(limit));
+    return new LimitPredicate(Integer.parseInt(limit));
-  }
-
-  static class LimitPredicate extends IntPredicate<ChangeData> {
-    LimitPredicate(int limit) {
-      super(FIELD_LIMIT, limit);
-    }
-
-    @Override
-    public boolean match(ChangeData object) {
-      return true;
-    }
-
-    @Override
-    public int getCost() {
-      return 0;
-    }
-  }
-
-  public Predicate<ChangeData> limit(int limit) {
-    return new LimitPredicate(limit);
   }
 
   @Operator

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

@@ -18,6 +18,6 @@ import com.google.gerrit.server.query.Predicate;
 import com.google.gerrit.server.query.QueryParseException;
 
 public interface ChangeQueryRewriter {
-  Predicate<ChangeData> rewrite(Predicate<ChangeData> in, int start)
+  Predicate<ChangeData> rewrite(Predicate<ChangeData> in, int start, int limit)
       throws QueryParseException;
 }

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

@@ -0,0 +1,47 @@
+// Copyright (C) 2014 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 static com.google.gerrit.server.query.change.ChangeQueryBuilder.FIELD_LIMIT;
+
+import com.google.gerrit.server.query.IntPredicate;
+import com.google.gerrit.server.query.Predicate;
+import com.google.gerrit.server.query.QueryBuilder;
+import com.google.gerrit.server.query.QueryParseException;
+
+public class LimitPredicate extends IntPredicate<ChangeData> {
+  @SuppressWarnings("unchecked")
+  public static Integer getLimit(Predicate<ChangeData> p) {
+    IntPredicate<?> ip = QueryBuilder.find(p, IntPredicate.class, FIELD_LIMIT);
+    return ip != null ? ip.intValue() : null;
+  }
+
+  public LimitPredicate(int limit) throws QueryParseException {
+    super(ChangeQueryBuilder.FIELD_LIMIT, limit);
+    if (limit <= 0) {
+      throw new QueryParseException("limit must be positive: " + limit);
+    }
+  }
+
+  @Override
+  public boolean match(ChangeData object) {
+    return true;
+  }
+
+  @Override
+  public int getCost() {
+    return 0;
+  }
+}

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

@@ -0,0 +1,405 @@
+// Copyright (C) 2014 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.gerrit.common.TimeUtil;
+import com.google.gerrit.common.data.LabelTypes;
+import com.google.gerrit.reviewdb.client.PatchSet;
+import com.google.gerrit.server.CurrentUser;
+import com.google.gerrit.server.config.TrackingFooters;
+import com.google.gerrit.server.data.ChangeAttribute;
+import com.google.gerrit.server.data.PatchSetAttribute;
+import com.google.gerrit.server.data.QueryStatsAttribute;
+import com.google.gerrit.server.events.EventFactory;
+import com.google.gerrit.server.project.ChangeControl;
+import com.google.gerrit.server.project.NoSuchChangeException;
+import com.google.gerrit.server.project.SubmitRuleEvaluator;
+import com.google.gerrit.server.query.QueryParseException;
+import com.google.gson.Gson;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+
+import org.eclipse.jgit.util.io.DisabledOutputStream;
+import org.joda.time.format.DateTimeFormat;
+import org.joda.time.format.DateTimeFormatter;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.io.BufferedWriter;
+import java.io.IOException;
+import java.io.OutputStream;
+import java.io.OutputStreamWriter;
+import java.io.PrintWriter;
+import java.lang.reflect.Field;
+import java.util.ArrayList;
+import java.util.Arrays;
+import java.util.Collection;
+import java.util.List;
+
+/**
+ * Change query implementation that outputs to a stream in the style of an SSH
+ * command.
+ */
+public class OutputStreamQuery {
+  private static final Logger log =
+      LoggerFactory.getLogger(OutputStreamQuery.class);
+
+  private static final DateTimeFormatter dtf =
+      DateTimeFormat.forPattern("yyyy-MM-dd HH:mm:ss zzz");
+
+  public static enum OutputFormat {
+    TEXT, JSON
+  }
+
+  private final QueryProcessor queryProcessor;
+  private final EventFactory eventFactory;
+  private final TrackingFooters trackingFooters;
+  private final CurrentUser user;
+
+  private OutputFormat outputFormat = OutputFormat.TEXT;
+  private boolean includePatchSets;
+  private boolean includeCurrentPatchSet;
+  private boolean includeApprovals;
+  private boolean includeComments;
+  private boolean includeFiles;
+  private boolean includeCommitMessage;
+  private boolean includeDependencies;
+  private boolean includeSubmitRecords;
+  private boolean includeAllReviewers;
+
+  private OutputStream outputStream = DisabledOutputStream.INSTANCE;
+  private PrintWriter out;
+
+  @Inject
+  OutputStreamQuery(QueryProcessor queryProcessor,
+      EventFactory eventFactory,
+      TrackingFooters trackingFooters,
+      CurrentUser user) {
+    this.queryProcessor = queryProcessor;
+    this.eventFactory = eventFactory;
+    this.trackingFooters = trackingFooters;
+    this.user = user;
+  }
+
+  void setLimit(int n) {
+    queryProcessor.setLimit(n);
+  }
+
+  public void setStart(int n) {
+    queryProcessor.setStart(n);
+  }
+
+  public void setIncludePatchSets(boolean on) {
+    includePatchSets = on;
+  }
+
+  public boolean getIncludePatchSets() {
+    return includePatchSets;
+  }
+
+  public void setIncludeCurrentPatchSet(boolean on) {
+    includeCurrentPatchSet = on;
+  }
+
+  public boolean getIncludeCurrentPatchSet() {
+    return includeCurrentPatchSet;
+  }
+
+  public void setIncludeApprovals(boolean on) {
+    includeApprovals = on;
+  }
+
+  public void setIncludeComments(boolean on) {
+    includeComments = on;
+  }
+
+  public void setIncludeFiles(boolean on) {
+    includeFiles = on;
+  }
+
+  public boolean getIncludeFiles() {
+    return includeFiles;
+  }
+
+  public void setIncludeDependencies(boolean on) {
+    includeDependencies = on;
+  }
+
+  public boolean getIncludeDependencies() {
+    return includeDependencies;
+  }
+
+  public void setIncludeCommitMessage(boolean on) {
+    includeCommitMessage = on;
+  }
+
+  public void setIncludeSubmitRecords(boolean on) {
+    includeSubmitRecords = on;
+  }
+
+  public void setIncludeAllReviewers(boolean on) {
+    includeAllReviewers = on;
+  }
+
+  public void setOutput(OutputStream out, OutputFormat fmt) {
+    this.outputStream = out;
+    this.outputFormat = fmt;
+  }
+
+  public void query(String queryString) throws IOException {
+    out = new PrintWriter( //
+        new BufferedWriter( //
+            new OutputStreamWriter(outputStream, "UTF-8")));
+    try {
+      if (queryProcessor.isDisabled()) {
+        ErrorMessage m = new ErrorMessage();
+        m.message = "query disabled";
+        show(m);
+        return;
+      }
+
+      try {
+        final QueryStatsAttribute stats = new QueryStatsAttribute();
+        stats.runTimeMilliseconds = TimeUtil.nowMs();
+
+        QueryResult results = queryProcessor.queryByString(queryString);
+        ChangeAttribute c = null;
+        for (ChangeData d : results.changes()) {
+          ChangeControl cc = d.changeControl().forUser(user);
+
+          LabelTypes labelTypes = cc.getLabelTypes();
+          c = eventFactory.asChangeAttribute(d.change());
+          eventFactory.extend(c, d.change());
+
+          if (!trackingFooters.isEmpty()) {
+            eventFactory.addTrackingIds(c,
+                trackingFooters.extract(d.commitFooters()));
+          }
+
+          if (includeAllReviewers) {
+            eventFactory.addAllReviewers(c, d.notes());
+          }
+
+          if (includeSubmitRecords) {
+            eventFactory.addSubmitRecords(c, new SubmitRuleEvaluator(d)
+                .setAllowClosed(true)
+                .setAllowDraft(true)
+                .canSubmit());
+          }
+
+          if (includeCommitMessage) {
+            eventFactory.addCommitMessage(c, d.commitMessage());
+          }
+
+          if (includePatchSets) {
+            if (includeFiles) {
+              eventFactory.addPatchSets(c, d.patches(),
+                includeApprovals ? d.approvals().asMap() : null,
+                includeFiles, d.change(), labelTypes);
+            } else {
+              eventFactory.addPatchSets(c, d.patches(),
+                  includeApprovals ? d.approvals().asMap() : null,
+                  labelTypes);
+            }
+          }
+
+          if (includeCurrentPatchSet) {
+            PatchSet current = d.currentPatchSet();
+            if (current != null) {
+              c.currentPatchSet = eventFactory.asPatchSetAttribute(current);
+              eventFactory.addApprovals(c.currentPatchSet,
+                  d.currentApprovals(), labelTypes);
+
+              if (includeFiles) {
+                eventFactory.addPatchSetFileNames(c.currentPatchSet,
+                    d.change(), d.currentPatchSet());
+              }
+            }
+          }
+
+          if (includeComments) {
+            eventFactory.addComments(c, d.messages());
+            if (includePatchSets) {
+              for (PatchSetAttribute attribute : c.patchSets) {
+                eventFactory.addPatchSetComments(attribute,  d.publishedComments());
+              }
+            }
+          }
+
+          if (includeDependencies) {
+            eventFactory.addDependencies(c, d.change());
+          }
+
+          show(c);
+        }
+
+        stats.rowCount = results.changes().size();
+        stats.moreChanges = results.moreChanges();
+        stats.runTimeMilliseconds =
+            TimeUtil.nowMs() - stats.runTimeMilliseconds;
+        show(stats);
+      } catch (OrmException err) {
+        log.error("Cannot execute query: " + queryString, err);
+
+        ErrorMessage m = new ErrorMessage();
+        m.message = "cannot query database";
+        show(m);
+
+      } catch (QueryParseException e) {
+        ErrorMessage m = new ErrorMessage();
+        m.message = e.getMessage();
+        show(m);
+      } catch (NoSuchChangeException e) {
+        log.error("Missing change: " + e.getMessage(), e);
+        ErrorMessage m = new ErrorMessage();
+        m.message = "missing change " + e.getMessage();
+        show(m);
+      }
+    } finally {
+      try {
+        out.flush();
+      } finally {
+        out = null;
+      }
+    }
+  }
+
+  private void show(Object data) {
+    switch (outputFormat) {
+      default:
+      case TEXT:
+        if (data instanceof ChangeAttribute) {
+          out.print("change ");
+          out.print(((ChangeAttribute) data).id);
+          out.print("\n");
+          showText(data, 1);
+        } else {
+          showText(data, 0);
+        }
+        out.print('\n');
+        break;
+
+      case JSON:
+        out.print(new Gson().toJson(data));
+        out.print('\n');
+        break;
+    }
+  }
+
+  private void showText(Object data, int depth) {
+    for (Field f : fieldsOf(data.getClass())) {
+      Object val;
+      try {
+        val = f.get(data);
+      } catch (IllegalArgumentException err) {
+        continue;
+      } catch (IllegalAccessException err) {
+        continue;
+      }
+      if (val == null) {
+        continue;
+      }
+
+      showField(f.getName(), val, depth);
+    }
+  }
+
+  private String indent(int spaces) {
+    if (spaces == 0) {
+      return "";
+    } else {
+      return String.format("%" + spaces + "s", " ");
+    }
+  }
+
+  private void showField(String field, Object value, int depth) {
+    final int spacesDepthRatio = 2;
+    String indent = indent(depth * spacesDepthRatio);
+    out.print(indent);
+    out.print(field);
+    out.print(':');
+    if (value instanceof String && ((String) value).contains("\n")) {
+      out.print(' ');
+      // Idention for multi-line text is
+      // current depth indetion + length of field + length of ": "
+      indent = indent(indent.length() + field.length() + spacesDepthRatio);
+      out.print(((String) value).replaceAll("\n", "\n" + indent).trim());
+      out.print('\n');
+    } else if (value instanceof Long && isDateField(field)) {
+      out.print(' ');
+      out.print(dtf.print(((Long) value) * 1000L));
+      out.print('\n');
+    } else if (isPrimitive(value)) {
+      out.print(' ');
+      out.print(value);
+      out.print('\n');
+    } else if (value instanceof Collection) {
+      out.print('\n');
+      boolean firstElement = true;
+      for (Object thing : ((Collection<?>) value)) {
+        // The name of the collection was initially printed at the beginning
+        // of this routine.  Beginning at the second sub-element, reprint
+        // the collection name so humans can separate individual elements
+        // with less strain and error.
+        //
+        if (firstElement) {
+          firstElement = false;
+        } else {
+          out.print(indent);
+          out.print(field);
+          out.print(":\n");
+        }
+        if (isPrimitive(thing)) {
+          out.print(' ');
+          out.print(value);
+          out.print('\n');
+        } else {
+          showText(thing, depth + 1);
+        }
+      }
+    } else {
+      out.print('\n');
+      showText(value, depth + 1);
+    }
+  }
+
+  private static boolean isPrimitive(Object value) {
+    return value instanceof String //
+        || value instanceof Number //
+        || value instanceof Boolean //
+        || value instanceof Enum;
+  }
+
+  private static boolean isDateField(String name) {
+    return "lastUpdated".equals(name) //
+        || "grantedOn".equals(name) //
+        || "timestamp".equals(name) //
+        || "createdOn".equals(name);
+  }
+
+  private List<Field> fieldsOf(Class<?> type) {
+    List<Field> r = new ArrayList<>();
+    if (type.getSuperclass() != null) {
+      r.addAll(fieldsOf(type.getSuperclass()));
+    }
+    r.addAll(Arrays.asList(type.getDeclaredFields()));
+    return r;
+  }
+
+  static class ErrorMessage {
+    public final String type = "error";
+    public String message;
+  }
+}

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

@@ -31,7 +31,6 @@ import com.google.inject.Provider;
 
 import org.kohsuke.args4j.Option;
 
-import java.util.BitSet;
 import java.util.Collections;
 import java.util.EnumSet;
 import java.util.List;
@@ -42,7 +41,6 @@ public class QueryChanges implements RestReadView<TopLevelResource> {
   private final ChangeJson json;
   private final QueryProcessor imp;
   private final Provider<CurrentUser> user;
-  private boolean reverse;
   private EnumSet<ListChangesOption> options;
 
   @Option(name = "--query", aliases = {"-q"}, metaVar = "QUERY", usage = "Query string")
@@ -137,32 +135,15 @@ public class QueryChanges implements RestReadView<TopLevelResource> {
   private List<List<ChangeInfo>> query0() throws OrmException,
       QueryParseException {
     int cnt = queries.size();
-    BitSet more = new BitSet(cnt);
+    List<QueryResult> results = imp.queryByStrings(queries);
-    List<List<ChangeData>> data = imp.queryChanges(queries);
+    List<List<ChangeInfo>> res = json.addOptions(options)
-    for (int n = 0; n < cnt; n++) {
+        .formatQueryResults(results);
-      List<ChangeData> changes = data.get(n);
-      if (imp.getLimit() > 0 && changes.size() > imp.getLimit()) {
-        if (reverse) {
-          changes = changes.subList(1, changes.size());
-        } else {
-          changes = changes.subList(0, imp.getLimit());
-        }
-        data.set(n, changes);
-        more.set(n, true);
-      }
-    }
-
-    List<List<ChangeInfo>> res = json.addOptions(options).formatList2(data);
     for (int n = 0; n < cnt; n++) {
       List<ChangeInfo> info = res.get(n);
-      if (more.get(n) && !info.isEmpty()) {
+      if (results.get(n).moreChanges()) {
-        if (reverse) {
-          info.get(0)._moreChanges = true;
-        } else {
         info.get(info.size() - 1)._moreChanges = true;
       }
     }
-    }
     return res;
   }
 }

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

@@ -14,494 +14,178 @@
 
 package com.google.gerrit.server.query.change;
 
-import com.google.common.base.MoreObjects;
+import static com.google.common.base.Preconditions.checkState;
+
 import com.google.common.collect.ImmutableList;
-import com.google.common.collect.Lists;
+import com.google.common.collect.Ordering;
-import com.google.gerrit.common.TimeUtil;
 import com.google.gerrit.common.data.GlobalCapability;
-import com.google.gerrit.common.data.LabelTypes;
-import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.server.CurrentUser;
-import com.google.gerrit.server.config.TrackingFooters;
+import com.google.gerrit.server.index.IndexPredicate;
-import com.google.gerrit.server.data.ChangeAttribute;
-import com.google.gerrit.server.data.PatchSetAttribute;
-import com.google.gerrit.server.data.QueryStatsAttribute;
-import com.google.gerrit.server.events.EventFactory;
-import com.google.gerrit.server.project.ChangeControl;
-import com.google.gerrit.server.project.NoSuchChangeException;
-import com.google.gerrit.server.project.SubmitRuleEvaluator;
 import com.google.gerrit.server.query.Predicate;
 import com.google.gerrit.server.query.QueryParseException;
-import com.google.gson.Gson;
 import com.google.gwtorm.server.OrmException;
 import com.google.gwtorm.server.ResultSet;
 import com.google.inject.Inject;
 
-import org.eclipse.jgit.util.io.DisabledOutputStream;
-import org.slf4j.Logger;
-import org.slf4j.LoggerFactory;
-
-import java.io.BufferedWriter;
-import java.io.IOException;
-import java.io.OutputStream;
-import java.io.OutputStreamWriter;
-import java.io.PrintWriter;
-import java.lang.reflect.Field;
-import java.text.SimpleDateFormat;
 import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.Collection;
-import java.util.Date;
 import java.util.List;
 
 public class QueryProcessor {
-  private static final Logger log =
-      LoggerFactory.getLogger(QueryProcessor.class);
-
-  public static enum OutputFormat {
-    TEXT, JSON
-  }
-
-  private final Gson gson = new Gson();
-  private final SimpleDateFormat sdf =
-      new SimpleDateFormat("yyyy-MM-dd HH:mm:ss zzz");
-
-  private final EventFactory eventFactory;
   private final ChangeQueryBuilder queryBuilder;
   private final ChangeQueryRewriter queryRewriter;
-  private final TrackingFooters trackingFooters;
+  private final int permittedLimit;
-  private final CurrentUser user;
-  private final int maxLimit;
 
-  private OutputFormat outputFormat = OutputFormat.TEXT;
+  private int limitFromCaller;
-  private int limit;
   private int start;
-  private boolean includePatchSets;
-  private boolean includeCurrentPatchSet;
-  private boolean includeApprovals;
-  private boolean includeComments;
-  private boolean includeFiles;
-  private boolean includeCommitMessage;
-  private boolean includeDependencies;
-  private boolean includeSubmitRecords;
-  private boolean includeAllReviewers;
-
-  private OutputStream outputStream = DisabledOutputStream.INSTANCE;
-  private PrintWriter out;
-  private boolean moreResults;
 
   @Inject
-  QueryProcessor(EventFactory eventFactory,
+  QueryProcessor(ChangeQueryBuilder.Factory queryBuilder,
-      ChangeQueryBuilder.Factory queryBuilder, CurrentUser currentUser,
+      CurrentUser currentUser,
-      ChangeQueryRewriter queryRewriter,
+      ChangeQueryRewriter queryRewriter) {
-      TrackingFooters trackingFooters) {
-    this.eventFactory = eventFactory;
     this.queryBuilder = queryBuilder.create(currentUser);
     this.queryRewriter = queryRewriter;
-    this.trackingFooters = trackingFooters;
+    this.permittedLimit = currentUser.getCapabilities()
-    this.user = currentUser;
-    this.maxLimit = currentUser.getCapabilities()
       .getRange(GlobalCapability.QUERY_LIMIT)
       .getMax();
-    this.moreResults = false;
   }
 
-  int getLimit() {
+  public ChangeQueryBuilder getQueryBuilder() {
-    return limit;
+    return queryBuilder;
   }
 
-  void setLimit(int n) {
+  public void setLimit(int n) {
-    limit = n;
+    limitFromCaller = n;
   }
 
   public void setStart(int n) {
     start = n;
   }
 
-  public void setIncludePatchSets(boolean on) {
+  /**
-    includePatchSets = on;
+   * Query for changes that match the query string.
-  }
+   *
-
+   * @see #queryChanges(List)
-  public boolean getIncludePatchSets() {
+   * @param queryString the query string to parse.
-    return includePatchSets;
+   * @return results of the query.
-  }
+   */
-
+  public QueryResult queryByString(String queryString)
-  public void setIncludeCurrentPatchSet(boolean on) {
+      throws OrmException, QueryParseException {
-    includeCurrentPatchSet = on;
+    return queryByStrings(ImmutableList.of(queryString)).get(0);
-  }
-
-  public boolean getIncludeCurrentPatchSet() {
-    return includeCurrentPatchSet;
-  }
-
-  public void setIncludeApprovals(boolean on) {
-    includeApprovals = on;
-  }
-
-  public void setIncludeComments(boolean on) {
-    includeComments = on;
-  }
-
-  public void setIncludeFiles(boolean on) {
-    includeFiles = on;
-  }
-
-  public boolean getIncludeFiles() {
-    return includeFiles;
-  }
-
-  public void setIncludeDependencies(boolean on) {
-    includeDependencies = on;
-  }
-
-  public boolean getIncludeDependencies() {
-    return includeDependencies;
-  }
-
-  public void setIncludeCommitMessage(boolean on) {
-    includeCommitMessage = on;
-  }
-
-  public void setIncludeSubmitRecords(boolean on) {
-    includeSubmitRecords = on;
-  }
-
-  public void setIncludeAllReviewers(boolean on) {
-    includeAllReviewers = on;
-  }
-
-  public void setOutput(OutputStream out, OutputFormat fmt) {
-    this.outputStream = out;
-    this.outputFormat = fmt;
   }
 
   /**
-   * Query for changes that match the query string.
+   * Perform multiple queries over a list of query strings.
+   *
+   * @see #queryChanges(List)
+   * @param queryStrings the query strings to parse.
+   * @return results of the queries, one list per input query.
+   */
+  public List<QueryResult> queryByStrings(List<String> queryStrings)
+      throws OrmException, QueryParseException {
+    List<Predicate<ChangeData>> queries = new ArrayList<>(queryStrings.size());
+    for (String qs : queryStrings) {
+      queries.add(queryBuilder.parse(qs));
+    }
+    return queryChanges(queries);
+  }
+
+  /**
+   * Query for changes that match a structured query.
+   *
+   * @see #queryChanges(List)
+   * @param query the query.
+   * @return results of the query.
+   */
+  public QueryResult queryChanges(Predicate<ChangeData> query)
+      throws OrmException, QueryParseException {
+    return queryChanges(ImmutableList.of(query)).get(0);
+  }
+
+  /*
+   * Perform multiple queries over a list of query strings.
    * <p>
    * If a limit was specified using {@link #setLimit(int)} this method may
    * return up to {@code limit + 1} results, allowing the caller to determine if
    * there are more than {@code limit} matches and suggest to its own caller
    * that the query could be retried with {@link #setStart(int)}.
+   *
+   * @param queries the queries.
+   * @return results of the queries, one list per input query.
    */
-  public List<ChangeData> queryChanges(String queryString)
+  public List<QueryResult> queryChanges(List<Predicate<ChangeData>> queries)
       throws OrmException, QueryParseException {
-    return queryChanges(ImmutableList.of(queryString)).get(0);
+    return queryChanges(null, queries);
   }
 
-  /**
+  static {
-   * Query for changes that match the query string.
+    // In addition to this assumption, this queryChanges assumes the basic
-   * <p>
+    // rewrites do not touch visibleto predicates either.
-   * If a limit was specified using {@link #setLimit(int)} this method may
+    checkState(
-   * return up to {@code limit + 1} results, allowing the caller to determine if
+        !IsVisibleToPredicate.class.isAssignableFrom(IndexPredicate.class),
-   * there are more than {@code limit} matches and suggest to its own caller
+        "QueryProcessor assumes visibleto is not used by the index rewriter.");
-   * that the query could be retried with {@link #setStart(int)}.
+  }
-   */
+
-  public List<List<ChangeData>> queryChanges(List<String> queries)
+  private List<QueryResult> queryChanges(List<String> queryStrings,
+      List<Predicate<ChangeData>> queries)
       throws OrmException, QueryParseException {
-    final Predicate<ChangeData> visibleToMe = queryBuilder.is_visible();
+    Predicate<ChangeData> visibleToMe = queryBuilder.is_visible();
     int cnt = queries.size();
 
     // Parse and rewrite all queries.
-    List<Integer> limits = Lists.newArrayListWithCapacity(cnt);
+    List<Integer> limits = new ArrayList<>(cnt);
-    List<ChangeDataSource> sources = Lists.newArrayListWithCapacity(cnt);
+    List<Predicate<ChangeData>> predicates = new ArrayList<>(cnt);
-    for (String query : queries) {
+    List<ChangeDataSource> sources = new ArrayList<>(cnt);
-      Predicate<ChangeData> q = parseQuery(query, visibleToMe);
+    for (Predicate<ChangeData> q : queries) {
-      Predicate<ChangeData> s = queryRewriter.rewrite(q, start);
+      int limit = getEffectiveLimit(q);
+      limits.add(limit);
+
+      // Always bump limit by 1, even if this results in exceeding the permitted
+      // max for this user. The only way to see if there are more changes is to
+      // ask for one more result from the query.
+      Predicate<ChangeData> s = queryRewriter.rewrite(q, start, limit + 1);
       if (!(s instanceof ChangeDataSource)) {
         q = Predicate.and(queryBuilder.status_open(), q);
-        s = queryRewriter.rewrite(q, start);
+        s = queryRewriter.rewrite(q, start, limit);
       }
       if (!(s instanceof ChangeDataSource)) {
         throw new QueryParseException("invalid query: " + s);
       }
-
-      // Don't trust QueryRewriter to have left the visible predicate.
       AndSource a = new AndSource(ImmutableList.of(s, visibleToMe), start);
-      limits.add(limit(q));
+      predicates.add(a);
       sources.add(a);
     }
 
     // Run each query asynchronously, if supported.
-    List<ResultSet<ChangeData>> matches = Lists.newArrayListWithCapacity(cnt);
+    List<ResultSet<ChangeData>> matches = new ArrayList<>(cnt);
     for (ChangeDataSource s : sources) {
       matches.add(s.read());
     }
 
-    List<List<ChangeData>> out = Lists.newArrayListWithCapacity(cnt);
+    List<QueryResult> out = new ArrayList<>(cnt);
     for (int i = 0; i < cnt; i++) {
-      List<ChangeData> results = matches.get(i).toList();
+      out.add(QueryResult.create(
-      if (results.size() > maxLimit) {
+          queryStrings != null ? queryStrings.get(i) : null,
-        moreResults = true;
+          predicates.get(i),
-      }
+          limits.get(i),
-      int limit = limits.get(i);
+          matches.get(i).toList()));
-      if (limit < results.size()) {
-        results = results.subList(0, limit);
-      }
-      out.add(results);
     }
     return out;
   }
 
-  public void query(String queryString) throws IOException {
-    out = new PrintWriter( //
-        new BufferedWriter( //
-            new OutputStreamWriter(outputStream, "UTF-8")));
-    try {
-      if (isDisabled()) {
-        ErrorMessage m = new ErrorMessage();
-        m.message = "query disabled";
-        show(m);
-        return;
-      }
-
-      try {
-        final QueryStatsAttribute stats = new QueryStatsAttribute();
-        stats.runTimeMilliseconds = TimeUtil.nowMs();
-
-        List<ChangeData> results = queryChanges(queryString);
-        ChangeAttribute c = null;
-        for (ChangeData d : results) {
-          ChangeControl cc = d.changeControl().forUser(user);
-
-          LabelTypes labelTypes = cc.getLabelTypes();
-          c = eventFactory.asChangeAttribute(d.change());
-          eventFactory.extend(c, d.change());
-
-          if (!trackingFooters.isEmpty()) {
-            eventFactory.addTrackingIds(c,
-                trackingFooters.extract(d.commitFooters()));
-          }
-
-          if (includeAllReviewers) {
-            eventFactory.addAllReviewers(c, d.notes());
-          }
-
-          if (includeSubmitRecords) {
-            eventFactory.addSubmitRecords(c, new SubmitRuleEvaluator(d)
-                .setAllowClosed(true)
-                .setAllowDraft(true)
-                .canSubmit());
-          }
-
-          if (includeCommitMessage) {
-            eventFactory.addCommitMessage(c, d.commitMessage());
-          }
-
-          if (includePatchSets) {
-            if (includeFiles) {
-              eventFactory.addPatchSets(c, d.patches(),
-                includeApprovals ? d.approvals().asMap() : null,
-                includeFiles, d.change(), labelTypes);
-            } else {
-              eventFactory.addPatchSets(c, d.patches(),
-                  includeApprovals ? d.approvals().asMap() : null,
-                  labelTypes);
-            }
-          }
-
-          if (includeCurrentPatchSet) {
-            PatchSet current = d.currentPatchSet();
-            if (current != null) {
-              c.currentPatchSet = eventFactory.asPatchSetAttribute(current);
-              eventFactory.addApprovals(c.currentPatchSet,
-                  d.currentApprovals(), labelTypes);
-
-              if (includeFiles) {
-                eventFactory.addPatchSetFileNames(c.currentPatchSet,
-                    d.change(), d.currentPatchSet());
-              }
-            }
-          }
-
-          if (includeComments) {
-            eventFactory.addComments(c, d.messages());
-            if (includePatchSets) {
-              for (PatchSetAttribute attribute : c.patchSets) {
-                eventFactory.addPatchSetComments(attribute,  d.publishedComments());
-              }
-            }
-          }
-
-          if (includeDependencies) {
-            eventFactory.addDependencies(c, d.change());
-          }
-
-          show(c);
-        }
-
-        stats.rowCount = results.size();
-        if (moreResults) {
-          stats.resumeSortKey = c.sortKey;
-        }
-        stats.runTimeMilliseconds =
-            TimeUtil.nowMs() - stats.runTimeMilliseconds;
-        show(stats);
-      } catch (OrmException err) {
-        log.error("Cannot execute query: " + queryString, err);
-
-        ErrorMessage m = new ErrorMessage();
-        m.message = "cannot query database";
-        show(m);
-
-      } catch (QueryParseException e) {
-        ErrorMessage m = new ErrorMessage();
-        m.message = e.getMessage();
-        show(m);
-      } catch (NoSuchChangeException e) {
-        log.error("Missing change: " + e.getMessage(), e);
-        ErrorMessage m = new ErrorMessage();
-        m.message = "missing change " + e.getMessage();
-        show(m);
-      }
-    } finally {
-      try {
-        out.flush();
-      } finally {
-        out = null;
-      }
-    }
-  }
-
   boolean isDisabled() {
-    return maxLimit <= 0;
+    return permittedLimit <= 0;
   }
 
-  private int limit(Predicate<ChangeData> s) {
+  private int getEffectiveLimit(Predicate<ChangeData> p) {
-    int n = MoreObjects.firstNonNull(ChangeQueryBuilder.getLimit(s), maxLimit);
+    List<Integer> possibleLimits = new ArrayList<>(3);
-    return limit > 0 ? Math.min(n, limit) + 1 : n + 1;
+    possibleLimits.add(permittedLimit);
+    if (limitFromCaller > 0) {
+      possibleLimits.add(limitFromCaller);
     }
-
+    Integer limitFromPredicate = LimitPredicate.getLimit(p);
-  private Predicate<ChangeData> parseQuery(String queryString,
+    if (limitFromPredicate != null) {
-      final Predicate<ChangeData> visibleToMe) throws QueryParseException {
+      possibleLimits.add(limitFromPredicate);
-    return Predicate.and(queryBuilder.parse(queryString),
-        queryBuilder.limit(limit > 0 ? Math.min(limit, maxLimit) + 1 : maxLimit),
-        visibleToMe);
     }
-
+    return Ordering.natural().min(possibleLimits);
-  private void show(Object data) {
-    switch (outputFormat) {
-      default:
-      case TEXT:
-        if (data instanceof ChangeAttribute) {
-          out.print("change ");
-          out.print(((ChangeAttribute) data).id);
-          out.print("\n");
-          showText(data, 1);
-        } else {
-          showText(data, 0);
-        }
-        out.print('\n');
-        break;
-
-      case JSON:
-        out.print(gson.toJson(data));
-        out.print('\n');
-        break;
-    }
-  }
-
-  private void showText(Object data, int depth) {
-    for (Field f : fieldsOf(data.getClass())) {
-      Object val;
-      try {
-        val = f.get(data);
-      } catch (IllegalArgumentException err) {
-        continue;
-      } catch (IllegalAccessException err) {
-        continue;
-      }
-      if (val == null) {
-        continue;
-      }
-
-      showField(f.getName(), val, depth);
-    }
-  }
-
-  private String indent(int spaces) {
-    if (spaces == 0) {
-      return "";
-    } else {
-      return String.format("%" + spaces + "s", " ");
-    }
-  }
-
-  private void showField(String field, Object value, int depth) {
-    final int spacesDepthRatio = 2;
-    String indent = indent(depth * spacesDepthRatio);
-    out.print(indent);
-    out.print(field);
-    out.print(':');
-    if (value instanceof String && ((String) value).contains("\n")) {
-      out.print(' ');
-      // Idention for multi-line text is
-      // current depth indetion + length of field + length of ": "
-      indent = indent(indent.length() + field.length() + spacesDepthRatio);
-      out.print(((String) value).replaceAll("\n", "\n" + indent).trim());
-      out.print('\n');
-    } else if (value instanceof Long && isDateField(field)) {
-      out.print(' ');
-      out.print(sdf.format(new Date(((Long) value) * 1000L)));
-      out.print('\n');
-    } else if (isPrimitive(value)) {
-      out.print(' ');
-      out.print(value);
-      out.print('\n');
-    } else if (value instanceof Collection) {
-      out.print('\n');
-      boolean firstElement = true;
-      for (Object thing : ((Collection<?>) value)) {
-        // The name of the collection was initially printed at the beginning
-        // of this routine.  Beginning at the second sub-element, reprint
-        // the collection name so humans can separate individual elements
-        // with less strain and error.
-        //
-        if (firstElement) {
-          firstElement = false;
-        } else {
-          out.print(indent);
-          out.print(field);
-          out.print(":\n");
-        }
-        if (isPrimitive(thing)) {
-          out.print(' ');
-          out.print(value);
-          out.print('\n');
-        } else {
-          showText(thing, depth + 1);
-        }
-      }
-    } else {
-      out.print('\n');
-      showText(value, depth + 1);
-    }
-  }
-
-  private static boolean isPrimitive(Object value) {
-    return value instanceof String //
-        || value instanceof Number //
-        || value instanceof Boolean //
-        || value instanceof Enum;
-  }
-
-  private static boolean isDateField(String name) {
-    return "lastUpdated".equals(name) //
-        || "grantedOn".equals(name) //
-        || "timestamp".equals(name) //
-        || "createdOn".equals(name);
-  }
-
-  private List<Field> fieldsOf(Class<?> type) {
-    List<Field> r = new ArrayList<>();
-    if (type.getSuperclass() != null) {
-      r.addAll(fieldsOf(type.getSuperclass()));
-    }
-    r.addAll(Arrays.asList(type.getDeclaredFields()));
-    return r;
-  }
-
-  static class ErrorMessage {
-    public final String type = "error";
-    public String message;
   }
 }

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

@@ -0,0 +1,59 @@
+// Copyright (C) 2014 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.auto.value.AutoValue;
+import com.google.gerrit.common.Nullable;
+import com.google.gerrit.server.query.Predicate;
+
+import java.util.List;
+
+/** Results of a query over changes. */
+@AutoValue
+public abstract class QueryResult {
+  static QueryResult create(@Nullable String query,
+      Predicate<ChangeData> predicate, int limit, List<ChangeData> changes) {
+    boolean moreChanges;
+    if (changes.size() > limit) {
+      moreChanges = true;
+      changes = changes.subList(0, limit);
+    } else {
+      moreChanges = false;
+    }
+    return new AutoValue_QueryResult(query, predicate, changes, moreChanges);
+  }
+
+  /**
+   * @return the original query string, or null if the query was created
+   *     programmatically.
+   */
+  @Nullable public abstract String query();
+
+  /**
+   * @return the predicate after all rewriting and other modification by the
+   *     query subsystem.
+   */
+  public abstract Predicate<ChangeData> predicate();
+
+  /** @return the query results. */
+  public abstract List<ChangeData> changes();
+
+  /**
+   * @return whether the query could be retried with
+   *     {@link QueryProcessor#setStart(int)} to produce more results. Never
+   *     true if {@link #changes()} is empty.
+   */
+  public abstract boolean moreChanges();
+}

gerrit-server/src/main/java/com/google/gerrit/server/schema/SchemaVersion.java

@@ -32,7 +32,7 @@ import java.util.List;
 /** A version of the database schema. */
 public abstract class SchemaVersion {
   /** The current schema version. */
-  public static final Class<Schema_101> C = Schema_101.class;
+  public static final Class<Schema_102> C = Schema_102.class;
 
   public static class Module extends AbstractModule {
     @Override

gerrit-server/src/main/java/com/google/gerrit/server/schema/Schema_102.java

@@ -0,0 +1,51 @@
+// Copyright (C) 2014 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.schema;
+
+import com.google.gerrit.reviewdb.server.ReviewDb;
+import com.google.gwtorm.jdbc.JdbcSchema;
+import com.google.gwtorm.schema.sql.DialectPostgreSQL;
+import com.google.gwtorm.schema.sql.SqlDialect;
+import com.google.gwtorm.server.OrmException;
+import com.google.inject.Inject;
+import com.google.inject.Provider;
+
+import java.sql.SQLException;
+import java.sql.Statement;
+
+public class Schema_102 extends SchemaVersion {
+  @Inject
+  Schema_102(Provider<Schema_100> prior) {
+    super(prior);
+  }
+
+  @Override
+  protected void migrateData(ReviewDb db, UpdateUI ui)
+      throws OrmException, SQLException {
+    JdbcSchema schema = (JdbcSchema) db;
+    SqlDialect dialect = schema.getDialect();
+    try (Statement stmt = schema.getConnection().createStatement()) {
+      stmt.executeUpdate("DROP INDEX changes_byProjectOpen");
+      if (dialect instanceof DialectPostgreSQL) {
+        stmt.executeUpdate("CREATE INDEX changes_byProjectOpen"
+            + " ON changes (dest_project_name, last_updated_on)"
+            + " WHERE open = 'Y'");
+      } else {
+        stmt.executeUpdate("CREATE INDEX changes_byProjectOpen"
+            + " ON changes (open, dest_project_name, last_updated_on)");
+      }
+    }
+  }
+}

gerrit-server/src/test/java/com/google/gerrit/server/git/LabelNormalizerTest.java

@@ -34,7 +34,6 @@ import com.google.gerrit.reviewdb.client.PatchSetApproval;
 import com.google.gerrit.reviewdb.client.PatchSetApproval.LabelId;
 import com.google.gerrit.reviewdb.client.PatchSetInfo;
 import com.google.gerrit.reviewdb.server.ReviewDb;
-import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.account.AccountManager;
 import com.google.gerrit.server.account.AuthRequest;
@@ -112,7 +111,6 @@ public class LabelNormalizerTest {
         new Change.Id(1), userId,
         new Branch.NameKey(allProjects, "refs/heads/master"),
         TimeUtil.nowTs());
-    ChangeUtil.computeSortKey(change);
     PatchSetInfo ps = new PatchSetInfo(new PatchSet.Id(change.getId(), 1));
     ps.setSubject("Test change");
     change.setCurrentPatchSet(ps);

gerrit-server/src/test/java/com/google/gerrit/server/index/IndexRewriteTest.java

@@ -97,7 +97,7 @@ public class IndexRewriteTest {
         parse("-status:abandoned (status:open OR status:merged)");
     assertEquals(
         query(parse("status:new OR status:submitted OR status:draft OR status:merged")),
-        rewrite.rewrite(in, 0));
+        rewrite.rewrite(in, 0, DEFAULT_MAX_QUERY_LIMIT));
   }
 
   @Test
@@ -158,24 +158,26 @@ public class IndexRewriteTest {
   }
 
   @Test
-  public void testLimit() throws Exception {
+  public void testLimitArgumentOverridesAllLimitPredicates() throws Exception {
-    Predicate<ChangeData> in = parse("file:a limit:3");
+    Predicate<ChangeData> in = parse("limit:1 file:a limit:3");
-    Predicate<ChangeData> out = rewrite(in);
+    Predicate<ChangeData> out = rewrite(in, 5);
     assertSame(AndSource.class, out.getClass());
     assertEquals(ImmutableList.of(
-          query(in.getChild(0), 3),
+          query(in.getChild(1), 5),
-          in.getChild(1)),
+          parse("limit:5"),
+          parse("limit:5")),
         out.getChildren());
   }
 
   @Test
   public void testStartIncreasesLimit() throws Exception {
+    int n = 3;
     Predicate<ChangeData> f = parse("file:a");
-    Predicate<ChangeData> l = parse("limit:3");
+    Predicate<ChangeData> l = parse("limit:" + n);
     Predicate<ChangeData> in = and(f, l);
-    assertEquals(and(query(f, 3), l), rewrite.rewrite(in, 0));
+    assertEquals(and(query(f, 3), parse("limit:3")), rewrite.rewrite(in, 0, n));
-    assertEquals(and(query(f, 4), l), rewrite.rewrite(in, 1));
+    assertEquals(and(query(f, 4), parse("limit:4")), rewrite.rewrite(in, 1, n));
-    assertEquals(and(query(f, 5), l), rewrite.rewrite(in, 2));
+    assertEquals(and(query(f, 5), parse("limit:5")), rewrite.rewrite(in, 2, n));
   }
 
   @Test
@@ -220,7 +222,12 @@ public class IndexRewriteTest {
 
   private Predicate<ChangeData> rewrite(Predicate<ChangeData> in)
       throws QueryParseException {
-    return rewrite.rewrite(in, 0);
+    return rewrite.rewrite(in, 0, DEFAULT_MAX_QUERY_LIMIT);
+  }
+
+  private Predicate<ChangeData> rewrite(Predicate<ChangeData> in, int limit)
+      throws QueryParseException {
+    return rewrite.rewrite(in, 0, limit);
   }
 
   private IndexedChangeQuery query(Predicate<ChangeData> p)

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

@@ -136,18 +136,22 @@ public abstract class AbstractQueryChangesTest {
     userAccount.setPreferredEmail("user@example.com");
     db.accounts().update(ImmutableList.of(userAccount));
     user = userFactory.create(userId);
+    requestContext.setContext(newRequestContext(userAccount.getId()));
+  }
 
-    requestContext.setContext(new RequestContext() {
+  private RequestContext newRequestContext(Account.Id requestUserId) {
+    final CurrentUser requestUser = userFactory.create(requestUserId);
+    return new RequestContext() {
       @Override
       public CurrentUser getCurrentUser() {
-        return user;
+        return requestUser;
       }
 
       @Override
       public Provider<ReviewDb> getReviewDbProvider() {
         return Providers.of(db);
       }
-    });
+    };
   }
 
   @After
@@ -543,9 +547,22 @@ public abstract class AbstractQueryChangesTest {
 
     List<ChangeInfo> results;
     for (int i = 1; i <= n + 2; i++) {
+      int expectedSize;
+      Boolean expectedMoreChanges;
+      if (i < n) {
+        expectedSize = i;
+        expectedMoreChanges = true;
+      } else {
+        expectedSize = n;
+        expectedMoreChanges = null;
+      }
       results = query("status:new limit:" + i);
-      assertThat(results).hasSize(Math.min(i, n));
+      String msg = "i=" + i;
+      assert_().withFailureMessage(msg).that(results).hasSize(expectedSize);
       assertResultEquals(last, results.get(0));
+      assert_().withFailureMessage(msg)
+          .that(results.get(results.size() - 1)._moreChanges)
+          .isEqualTo(expectedMoreChanges);
     }
   }
 
@@ -1031,6 +1048,49 @@ public abstract class AbstractQueryChangesTest {
     assertThat(query("repo")).hasSize(6);
   }
 
+  @Test
+  public void implicitVisibleTo() throws Exception {
+    TestRepository<InMemoryRepository> repo = createProject("repo");
+    Change change1 = newChange(repo, null, null, userId.get(), null).insert();
+    ChangeInserter ins2 = newChange(repo, null, null, userId.get(), null);
+    Change change2 = ins2.getChange();
+    change2.setStatus(Change.Status.DRAFT);
+    ins2.insert();
+
+    String q = "project:repo";
+    List<ChangeInfo> results = query(q);
+    assertThat(results).hasSize(2);
+    assertResultEquals(change2, results.get(0));
+    assertResultEquals(change1, results.get(1));
+
+    // Second user cannot see first user's drafts.
+    requestContext.setContext(newRequestContext(accountManager
+        .authenticate(AuthRequest.forUser("anotheruser")).getAccountId()));
+    assertResultEquals(change1, queryOne(q));
+  }
+
+  @Test
+  public void explicitVisibleTo() throws Exception {
+    TestRepository<InMemoryRepository> repo = createProject("repo");
+    Change change1 = newChange(repo, null, null, userId.get(), null).insert();
+    ChangeInserter ins2 = newChange(repo, null, null, userId.get(), null);
+    Change change2 = ins2.getChange();
+    change2.setStatus(Change.Status.DRAFT);
+    ins2.insert();
+
+    String q = "project:repo";
+    List<ChangeInfo> results = query(q);
+    assertThat(results).hasSize(2);
+    assertResultEquals(change2, results.get(0));
+    assertResultEquals(change1, results.get(1));
+
+    // Second user cannot see first user's drafts.
+    Account.Id user2 = accountManager
+        .authenticate(AuthRequest.forUser("anotheruser"))
+        .getAccountId();
+    assertResultEquals(change1, queryOne(q + " visibleto:" + user2.get()));
+  }
+
   protected ChangeInserter newChange(
       TestRepository<InMemoryRepository> repo,
       @Nullable RevCommit commit, @Nullable String key, @Nullable Integer owner,

gerrit-server/src/test/java/com/google/gerrit/testutil/TestChanges.java

@@ -25,7 +25,6 @@ import com.google.gerrit.reviewdb.client.PatchSet;
 import com.google.gerrit.reviewdb.client.PatchSetInfo;
 import com.google.gerrit.reviewdb.client.Project;
 import com.google.gerrit.reviewdb.client.RevId;
-import com.google.gerrit.server.ChangeUtil;
 import com.google.gerrit.server.IdentifiedUser;
 import com.google.gerrit.server.config.AllUsersName;
 import com.google.gerrit.server.config.AllUsersNameProvider;
@@ -114,6 +113,5 @@ public class TestChanges {
         change.getId(), curr != null ? curr.get() + 1 : 1));
     ps.setSubject("Change subject");
     change.setCurrentPatchSet(ps);
-    ChangeUtil.computeSortKey(change);
   }
 }

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

@@ -14,7 +14,8 @@
 
 package com.google.gerrit.sshd.commands;
 
-import com.google.gerrit.server.query.change.QueryProcessor;
+import com.google.gerrit.server.query.change.OutputStreamQuery;
+import com.google.gerrit.server.query.change.OutputStreamQuery.OutputFormat;
 import com.google.gerrit.sshd.CommandMetaData;
 import com.google.gerrit.sshd.SshCommand;
 import com.google.inject.Inject;
@@ -27,10 +28,10 @@ import java.util.List;
 @CommandMetaData(name = "query", description = "Query the change database")
 class Query extends SshCommand {
   @Inject
-  private QueryProcessor processor;
+  private OutputStreamQuery processor;
 
   @Option(name = "--format", metaVar = "FMT", usage = "Output display format")
-  void setFormat(QueryProcessor.OutputFormat format) {
+  void setFormat(OutputFormat format) {
     processor.setOutput(out, format);
   }
 
@@ -97,7 +98,7 @@ class Query extends SshCommand {
 
   @Override
   protected void parseCommandLine() throws UnloggedFailure {
-    processor.setOutput(out, QueryProcessor.OutputFormat.TEXT);
+    processor.setOutput(out, OutputFormat.TEXT);
     super.parseCommandLine();
     if (processor.getIncludeFiles() &&
         !(processor.getIncludePatchSets() || processor.getIncludeCurrentPatchSet())) {