Implement mergedafter and mergedbefore change search operator

This implementation of merged-sensitive search operator was chosen to be
consistent with the existing after/before operators.

Other discussed alternatives:
- new operators, merged:'RELATION''TIMESTAMP' and
updated:'RELATION''TIMESTAMP'
- search on merged date for submitted CLs, on created date for pending
CLs
- add a modifier to specify the search strategy.
- add a modifier for the sorting strategy.

The change includes:
- Index the changes on mergedOn date.
- Sort the index on mergedOn before changeId.
- Add mergedafter and mergedbefore operators to change query.

As a future work, we could sort on merged date for the merge search
operators.

Change-Id: I68f36a8b8aed29a837aca84f8b24774f039fccd6

Documentation/user-search.txt

@@ -92,6 +92,18 @@ Changes modified after the given 'TIME', inclusive. Must be in the
 format `2006-01-02[ 15:04:05[.890][ -0700]]`; omitting the time defaults
 to 00:00:00 and omitting the timezone defaults to UTC.
 
+[[mergedbefore]]
+mergedbefore:'TIME'::
++
+Changes merged before the given 'TIME'. The matching behaviour is consistent
+with `before:'TIME'`.
+
+[[mergedafter]]
+mergedafter:'TIME'::
++
+Changes merged after the given 'TIME'. The matching behaviour is consistent
+with `after:'TIME'`.
+
 [[change]]
 change:'ID'::
 +

java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java

@@ -84,6 +84,9 @@ abstract class AbstractElasticIndex<K, V> implements Index<K, V> {
   protected static final String BULK = "_bulk";
   protected static final String MAPPINGS = "mappings";
   protected static final String ORDER = "order";
+  protected static final String DESC_SORT_ORDER = "desc";
+  protected static final String ASC_SORT_ORDER = "asc";
+  protected static final String UNMAPPED_TYPE = "unmapped_type";
   protected static final String SEARCH = "_search";
   protected static final String SETTINGS = "settings";
 
@@ -298,7 +301,7 @@ abstract class AbstractElasticIndex<K, V> implements Index<K, V> {
 
   protected JsonArray getSortArray(String idFieldName) {
     JsonObject properties = new JsonObject();
-    properties.addProperty(ORDER, "asc");
+    properties.addProperty(ORDER, ASC_SORT_ORDER);
 
     JsonArray sortArray = new JsonArray();
     addNamedElement(idFieldName, properties, sortArray);

java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java

@@ -61,6 +61,9 @@ import com.google.gson.JsonElement;
 import com.google.gson.JsonObject;
 import com.google.inject.Inject;
 import com.google.inject.assistedinject.Assisted;
+import java.sql.Timestamp;
+import java.time.Instant;
+import java.time.format.DateTimeFormatter;
 import java.util.Collections;
 import java.util.List;
 import java.util.Optional;
@@ -158,14 +161,24 @@ class ElasticChangeIndex extends AbstractElasticIndex<Change.Id, ChangeData>
 
   private JsonArray getSortArray() {
     JsonObject properties = new JsonObject();
-    properties.addProperty(ORDER, "desc");
+    properties.addProperty(ORDER, DESC_SORT_ORDER);
 
     JsonArray sortArray = new JsonArray();
     addNamedElement(ChangeField.UPDATED.getName(), properties, sortArray);
+    addNamedElement(ChangeField.MERGED_ON.getName(), getMergedOnSortOptions(), sortArray);
     addNamedElement(idField.getName(), properties, sortArray);
     return sortArray;
   }
 
+  private JsonObject getMergedOnSortOptions() {
+    JsonObject sortOptions = new JsonObject();
+    sortOptions.addProperty(ORDER, DESC_SORT_ORDER);
+    // Ignore the sort field if it does not exist in index. Otherwise the search would fail on open
+    // changes, because the corresponding documents do not have mergedOn field.
+    sortOptions.addProperty(UNMAPPED_TYPE, ElasticMapping.TIMESTAMP_FIELD_TYPE);
+    return sortOptions;
+  }
+
   private String getURI(List<String> types) {
     return String.join(",", types);
   }
@@ -390,6 +403,10 @@ class ElasticChangeIndex extends AbstractElasticIndex<Change.Id, ChangeData>
           cd);
     }
 
+    if (fields.contains(ChangeField.MERGED_ON.getName())) {
+      decodeMergedOn(source, cd);
+    }
+
     return cd;
   }
 
@@ -425,4 +442,18 @@ class ElasticChangeIndex extends AbstractElasticIndex<Change.Id, ChangeData>
     }
     out.setUnresolvedCommentCount(count.getAsInt());
   }
+
+  private void decodeMergedOn(JsonObject doc, ChangeData out) {
+    JsonElement mergedOnField = doc.get(ChangeField.MERGED_ON.getName());
+
+    Timestamp mergedOn = null;
+    if (mergedOnField != null) {
+      // Parse from ElasticMapping.TIMESTAMP_FIELD_FORMAT.
+      // We currently use built-in ISO-based dateOptionalTime.
+      // https://www.elastic.co/guide/en/elasticsearch/reference/current/mapping-date-format.html#built-in-date-formats
+      DateTimeFormatter isoFormatter = DateTimeFormatter.ISO_INSTANT;
+      mergedOn = Timestamp.from(Instant.from(isoFormatter.parse(mergedOnField.getAsString())));
+    }
+    out.setMergedOn(mergedOn);
+  }
 }

java/com/google/gerrit/elasticsearch/ElasticMapping.java

@@ -21,6 +21,10 @@ import com.google.gerrit.index.Schema;
 import java.util.Map;
 
 class ElasticMapping {
+
+  protected static final String TIMESTAMP_FIELD_TYPE = "date";
+  protected static final String TIMESTAMP_FIELD_FORMAT = "dateOptionalTime";
+
   static MappingProperties createMapping(Schema<?> schema, ElasticQueryAdapter adapter) {
     ElasticMapping.Builder mapping = new ElasticMapping.Builder(adapter);
     for (FieldDef<?, ?> field : schema.getFields().values()) {
@@ -71,9 +75,9 @@ class ElasticMapping {
     }
 
     Builder addTimestamp(String name) {
-      FieldProperties properties = new FieldProperties("date");
+      FieldProperties properties = new FieldProperties(TIMESTAMP_FIELD_TYPE);
-      properties.type = "date";
+      properties.type = TIMESTAMP_FIELD_TYPE;
-      properties.format = "dateOptionalTime";
+      properties.format = TIMESTAMP_FIELD_FORMAT;
       fields.put(name, properties);
       return this;
     }

java/com/google/gerrit/lucene/ChangeSubIndex.java

@@ -17,6 +17,7 @@ package com.google.gerrit.lucene;
 import static com.google.common.collect.Iterables.getOnlyElement;
 import static com.google.gerrit.lucene.LuceneChangeIndex.ID2_SORT_FIELD;
 import static com.google.gerrit.lucene.LuceneChangeIndex.ID_SORT_FIELD;
+import static com.google.gerrit.lucene.LuceneChangeIndex.MERGED_ON_SORT_FIELD;
 import static com.google.gerrit.lucene.LuceneChangeIndex.UPDATED_SORT_FIELD;
 import static com.google.gerrit.server.index.change.ChangeSchemaDefinitions.NAME;
 
@@ -110,6 +111,9 @@ public class ChangeSubIndex extends AbstractLuceneIndex<Change.Id, ChangeData>
     } else if (f == ChangeField.UPDATED) {
       long t = ((Timestamp) getOnlyElement(values.getValues())).getTime();
       doc.add(new NumericDocValuesField(UPDATED_SORT_FIELD, t));
+    } else if (f == ChangeField.MERGED_ON) {
+      long t = ((Timestamp) getOnlyElement(values.getValues())).getTime();
+      doc.add(new NumericDocValuesField(MERGED_ON_SORT_FIELD, t));
     }
     super.add(doc, values);
   }

java/com/google/gerrit/lucene/LuceneChangeIndex.java

@@ -72,6 +72,7 @@ import com.google.inject.assistedinject.Assisted;
 import com.google.protobuf.MessageLite;
 import java.io.IOException;
 import java.nio.file.Path;
+import java.sql.Timestamp;
 import java.util.ArrayList;
 import java.util.Collection;
 import java.util.Iterator;
@@ -110,6 +111,7 @@ public class LuceneChangeIndex implements ChangeIndex {
   private static final FluentLogger logger = FluentLogger.forEnclosingClass();
 
   static final String UPDATED_SORT_FIELD = sortFieldName(ChangeField.UPDATED);
+  static final String MERGED_ON_SORT_FIELD = sortFieldName(ChangeField.MERGED_ON);
   static final String ID_SORT_FIELD = sortFieldName(ChangeField.LEGACY_ID);
   static final String ID2_SORT_FIELD = sortFieldName(ChangeField.LEGACY_ID_STR);
 
@@ -140,6 +142,7 @@ public class LuceneChangeIndex implements ChangeIndex {
   private static final String UNRESOLVED_COMMENT_COUNT_FIELD =
       ChangeField.UNRESOLVED_COMMENT_COUNT.getName();
   private static final String ATTENTION_SET_FULL_FIELD = ChangeField.ATTENTION_SET_FULL.getName();
+  private static final String MERGED_ON_FIELD = ChangeField.MERGED_ON.getName();
 
   @FunctionalInterface
   static interface IdTerm {
@@ -320,6 +323,7 @@ public class LuceneChangeIndex implements ChangeIndex {
   private Sort getSort() {
     return new Sort(
         new SortField(UPDATED_SORT_FIELD, SortField.Type.LONG, true),
+        new SortField(MERGED_ON_SORT_FIELD, SortField.Type.LONG, true),
         new SortField(idSortFieldName, SortField.Type.LONG, true));
   }
 
@@ -563,6 +567,9 @@ public class LuceneChangeIndex implements ChangeIndex {
     if (fields.contains(REF_STATE_PATTERN_FIELD)) {
       decodeRefStatePatterns(doc, cd);
     }
+    if (fields.contains(MERGED_ON_FIELD)) {
+      decodeMergedOn(doc, cd);
+    }
 
     decodeUnresolvedCommentCount(doc, cd);
     decodeTotalCommentCount(doc, cd);
@@ -719,6 +726,16 @@ public class LuceneChangeIndex implements ChangeIndex {
     }
   }
 
+  private void decodeMergedOn(ListMultimap<String, IndexableField> doc, ChangeData cd) {
+    IndexableField mergedOnField =
+        Iterables.getFirst(doc.get(MERGED_ON_FIELD), /* defaultValue= */ null);
+    Timestamp mergedOn = null;
+    if (mergedOnField != null && mergedOnField.numericValue() != null) {
+      mergedOn = new Timestamp(mergedOnField.numericValue().longValue());
+    }
+    cd.setMergedOn(mergedOn);
+  }
+
   private static <T> List<T> decodeProtos(
       ListMultimap<String, IndexableField> doc, String fieldName, ProtoConverter<?, T> converter) {
     return doc.get(fieldName).stream()

java/com/google/gerrit/server/index/change/ChangeField.java

@@ -152,6 +152,12 @@ public class ChangeField {
   public static final FieldDef<ChangeData, Timestamp> UPDATED =
       timestamp("updated2").stored().build(changeGetter(Change::getLastUpdatedOn));
 
+  /** When this change was merged, time since January 1, 1970. */
+  public static final FieldDef<ChangeData, Timestamp> MERGED_ON =
+      timestamp(ChangeQueryBuilder.FIELD_MERGED_ON)
+          .stored()
+          .build(cd -> cd.getMergedOn().orElse(null));
+
   /** List of full file paths modified in the current patch set. */
   public static final FieldDef<ChangeData, Iterable<String>> PATH =
       // Named for backwards compatibility.

java/com/google/gerrit/server/index/change/ChangeSchemaDefinitions.java

@@ -130,9 +130,14 @@ public class ChangeSchemaDefinitions extends SchemaDefinitions<ChangeData> {
           .build();
 
   /** Added new fields {@link ChangeField#MERGE} */
+  @Deprecated
   static final Schema<ChangeData> V60 =
       new Schema.Builder<ChangeData>().add(V59).add(ChangeField.MERGE).build();
 
+  /** Added new field {@link ChangeField#MERGED_ON} */
+  static final Schema<ChangeData> V61 =
+      new Schema.Builder<ChangeData>().add(V60).add(ChangeField.MERGED_ON).build();
+
   /**
    * Name of the change index to be used when contacting index backends or loading configurations.
    */

java/com/google/gerrit/server/query/change/ChangeQueryBuilder.java

@@ -169,6 +169,7 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData, ChangeQueryBuil
   public static final String FIELD_LIMIT = "limit";
   public static final String FIELD_MERGE = "merge";
   public static final String FIELD_MERGEABLE = "mergeable2";
+  public static final String FIELD_MERGED_ON = "mergedon";
   public static final String FIELD_MESSAGE = "message";
   public static final String FIELD_OWNER = "owner";
   public static final String FIELD_OWNERIN = "ownerin";
@@ -205,6 +206,9 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData, ChangeQueryBuil
   public static final String ARG_ID_OWNER = "owner";
   public static final Account.Id OWNER_ACCOUNT_ID = Account.id(0);
 
+  public static final String OPERATOR_MERGED_BEFORE = "mergedbefore";
+  public static final String OPERATOR_MERGED_AFTER = "mergedafter";
+
   // Operators to match on the last time the change was updated. Naming for legacy reasons.
   public static final String OPERATOR_BEFORE = "before";
   public static final String OPERATOR_AFTER = "after";
@@ -493,6 +497,28 @@ public class ChangeQueryBuilder extends QueryBuilder<ChangeData, ChangeQueryBuil
     return after(value);
   }
 
+  @Operator
+  public Predicate<ChangeData> mergedBefore(String value) throws QueryParseException {
+    if (!args.index.getSchema().hasField(ChangeField.MERGED_ON)) {
+      throw new QueryParseException(
+          String.format(
+              "'%s' operator is not supported by change index version", OPERATOR_MERGED_BEFORE));
+    }
+    return new BeforePredicate(
+        ChangeField.MERGED_ON, ChangeQueryBuilder.OPERATOR_MERGED_BEFORE, value);
+  }
+
+  @Operator
+  public Predicate<ChangeData> mergedAfter(String value) throws QueryParseException {
+    if (!args.index.getSchema().hasField(ChangeField.MERGED_ON)) {
+      throw new QueryParseException(
+          String.format(
+              "'%s' operator is not supported by change index version", OPERATOR_MERGED_AFTER));
+    }
+    return new AfterPredicate(
+        ChangeField.MERGED_ON, ChangeQueryBuilder.OPERATOR_MERGED_AFTER, value);
+  }
+
   @Operator
   public Predicate<ChangeData> change(String query) throws QueryParseException {
     Optional<ChangeTriplet> triplet = ChangeTriplet.parse(query);

javatests/com/google/gerrit/server/query/change/AbstractQueryChangesTest.java

@@ -1672,6 +1672,186 @@ public abstract class AbstractQueryChangesTest extends GerritServerTests {
     }
   }
 
+  @Test
+  public void mergedOperatorSupportedByIndexVersion() throws Exception {
+    if (getSchemaVersion() < 61) {
+      assertMissingField(ChangeField.MERGED_ON);
+      assertFailingQuery(
+          "mergedbefore:2009-10-01",
+          "'mergedbefore' operator is not supported by change index version");
+      assertFailingQuery(
+          "mergedafter:2009-10-01",
+          "'mergedafter' operator is not supported by change index version");
+    } else {
+      assertThat(getSchema().hasField(ChangeField.MERGED_ON)).isTrue();
+    }
+  }
+
+  @Test
+  public void byMergedBefore() throws Exception {
+    assume().that(getSchema().hasField(ChangeField.MERGED_ON)).isTrue();
+    long thirtyHoursInMs = MILLISECONDS.convert(30, HOURS);
+
+    // Stop the clock, will set time to specific test values.
+    resetTimeWithClockStep(0, MILLISECONDS);
+    TestRepository<Repo> repo = createProject("repo");
+    long startMs = TestTimeUtil.START.toEpochMilli();
+    TestTimeUtil.setClock(new Timestamp(startMs));
+    Change change1 = insert(repo, newChange(repo));
+    Change change2 = insert(repo, newChange(repo));
+    Change change3 = insert(repo, newChange(repo));
+
+    TestTimeUtil.setClock(new Timestamp(startMs + thirtyHoursInMs));
+    submit(change3);
+    TestTimeUtil.setClock(new Timestamp(startMs + 2 * thirtyHoursInMs));
+    submit(change2);
+    TestTimeUtil.setClock(new Timestamp(startMs + 3 * thirtyHoursInMs));
+    // Put another approval on the change, just to update it.
+    approve(change1);
+    approve(change3);
+
+    assertThat(TimeUtil.nowMs()).isEqualTo(startMs + 3 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change3)).isEqualTo(startMs + 3 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change2)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change1)).isEqualTo(startMs + 3 * thirtyHoursInMs);
+
+    // Verify that:
+    // 1. Change1 was not submitted and should be never returned.
+    // 2. Change2 was merged on 2009-10-02 03:00:00 -0000
+    // 3. Change3 was merged on 2009-10-03 09:00:00.0 -0000
+    assertQuery("mergedbefore:2009-10-01");
+    // Changes excluded on the date submitted.
+    assertQuery("mergedbefore:2009-10-02");
+    assertQuery("mergedbefore:\"2009-10-01 22:59:00 -0400\"");
+    assertQuery("mergedbefore:\"2009-10-01 02:59:00\"");
+    assertQuery("mergedbefore:\"2009-10-01 23:02:00 -0400\"", change3);
+    assertQuery("mergedbefore:\"2009-10-02 03:02:00 -0000\"", change3);
+    assertQuery("mergedbefore:\"2009-10-02 03:02:00\"", change3);
+    assertQuery("mergedbefore:2009-10-03", change3);
+    // Changes are sorted by lastUpdatedOn first, then by mergedOn.
+    // Even though Change2 was merged after Change3, Change3 is returned first.
+    assertQuery("mergedbefore:2009-10-04", change3, change2);
+
+    // Same test as above, but using filter code path.
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:2009-10-01"));
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:2009-10-02"));
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-01 22:59:00 -0400\""));
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-01 02:59:00\""));
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-01 23:02:00 -0400\""), change3);
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-02 03:02:00 -0000\""), change3);
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:\"2009-10-02 03:02:00\""), change3);
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:2009-10-03"), change3);
+    assertQuery(makeIndexedPredicateFilterQuery("mergedbefore:2009-10-04"), change3, change2);
+  }
+
+  @Test
+  public void byMergedAfter() throws Exception {
+    assume().that(getSchema().hasField(ChangeField.MERGED_ON)).isTrue();
+    long thirtyHoursInMs = MILLISECONDS.convert(30, HOURS);
+
+    // Stop the clock, will set time to specific test values.
+    resetTimeWithClockStep(0, MILLISECONDS);
+    TestRepository<Repo> repo = createProject("repo");
+    long startMs = TestTimeUtil.START.toEpochMilli();
+    TestTimeUtil.setClock(new Timestamp(startMs));
+    Change change1 = insert(repo, newChange(repo));
+    Change change2 = insert(repo, newChange(repo));
+    Change change3 = insert(repo, newChange(repo));
+    assertThat(TimeUtil.nowMs()).isEqualTo(startMs);
+
+    TestTimeUtil.setClock(new Timestamp(startMs + thirtyHoursInMs));
+    submit(change3);
+
+    TestTimeUtil.setClock(new Timestamp(startMs + 2 * thirtyHoursInMs));
+    submit(change2);
+
+    TestTimeUtil.setClock(new Timestamp(startMs + 3 * thirtyHoursInMs));
+    // Put another approval on the change, just to update it.
+    approve(change1);
+    approve(change3);
+
+    assertThat(TimeUtil.nowMs()).isEqualTo(startMs + 3 * thirtyHoursInMs);
+
+    assertThat(lastUpdatedMsApi(change3)).isEqualTo(startMs + 3 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change2)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change1)).isEqualTo(startMs + 3 * thirtyHoursInMs);
+
+    // Verify that:
+    // 1. Change1 was not submitted and should be never returned.
+    // 2. Change2 was merged on 2009-10-02 03:00:00 -0000
+    // 3. Change3 was merged on 2009-10-03 09:00:00.0 -0000
+    assertQuery("mergedafter:2009-10-01", change3, change2);
+    // Changes are sorted by lastUpdatedOn first, then by mergedOn.
+    // Even though Change2 was merged after Change3, Change3 is returned first.
+    assertQuery("mergedafter:\"2009-10-01 22:59:00 -0400\"", change3, change2);
+    assertQuery("mergedafter:\"2009-10-02 02:59:00 -0000\"", change3, change2);
+    assertQuery("mergedafter:\"2009-10-01 23:02:00 -0400\"", change2);
+    assertQuery("mergedafter:\"2009-10-02 03:02:00 -0000\"", change2);
+    // Changes included on the date submitted.
+    assertQuery("mergedafter:2009-10-02", change3, change2);
+    assertQuery("mergedafter:2009-10-03", change2);
+
+    // Same test as above, but using filter code path.
+
+    assertQuery(makeIndexedPredicateFilterQuery("mergedafter:2009-10-01"), change3, change2);
+    // Changes are sorted by lastUpdatedOn first, then by mergedOn.
+    // Even though Change2 was merged after Change3, Change3 is returned first.
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedafter:\"2009-10-01 22:59:00 -0400\""),
+        change3,
+        change2);
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedafter:\"2009-10-02 02:59:00 -0000\""),
+        change3,
+        change2);
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedafter:\"2009-10-01 23:02:00 -0400\""), change2);
+    assertQuery(
+        makeIndexedPredicateFilterQuery("mergedafter:\"2009-10-02 03:02:00 -0000\""), change2);
+    // Changes included on the date submitted.
+    assertQuery(makeIndexedPredicateFilterQuery("mergedafter:2009-10-02"), change3, change2);
+    assertQuery(makeIndexedPredicateFilterQuery("mergedafter:2009-10-03"), change2);
+  }
+
+  @Test
+  public void updatedThenMergedOrder() throws Exception {
+    assume().that(getSchema().hasField(ChangeField.MERGED_ON)).isTrue();
+    long thirtyHoursInMs = MILLISECONDS.convert(30, HOURS);
+
+    // Stop the clock, will set time to specific test values.
+    resetTimeWithClockStep(0, MILLISECONDS);
+    TestRepository<Repo> repo = createProject("repo");
+    long startMs = TestTimeUtil.START.toEpochMilli();
+    TestTimeUtil.setClock(new Timestamp(startMs));
+
+    Change change1 = insert(repo, newChange(repo));
+    Change change2 = insert(repo, newChange(repo));
+    Change change3 = insert(repo, newChange(repo));
+
+    TestTimeUtil.setClock(new Timestamp(startMs + thirtyHoursInMs));
+    submit(change2);
+    submit(change3);
+    TestTimeUtil.setClock(new Timestamp(startMs + 2 * thirtyHoursInMs));
+    // Approve post submit just to update lastUpdatedOn
+    approve(change3);
+    approve(change2);
+    submit(change1);
+
+    // All Changes were last updated at the same time.
+    assertThat(lastUpdatedMsApi(change3)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change2)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+    assertThat(lastUpdatedMsApi(change1)).isEqualTo(startMs + 2 * thirtyHoursInMs);
+
+    // Changes are sorted by lastUpdatedOn first, then by mergedOn, then by Id in reverse order.
+    // 1. Change3 and Change2 were merged at the same time, but Change3 ID > Change2 ID.
+    // 2. Change1 ID < Change3 ID & Change2 ID but it was merged last.
+    assertQuery("mergedbefore:2009-10-06", change1, change3, change2);
+    assertQuery("mergedafter:2009-09-30", change1, change3, change2);
+    assertQuery("status:merged", change1, change3, change2);
+  }
+
   @Test
   public void bySize() throws Exception {
     TestRepository<Repo> repo = createProject("repo");
@@ -3636,6 +3816,20 @@ public abstract class AbstractQueryChangesTest extends GerritServerTests {
     return c.getLastUpdatedOn().getTime();
   }
 
+  // Get the last  updated time from ChangeApi
+  protected long lastUpdatedMsApi(Change c) throws Exception {
+    return gApi.changes().id(c.getChangeId()).get().updated.getTime();
+  }
+
+  protected void approve(Change change) throws Exception {
+    gApi.changes().id(change.getChangeId()).current().review(ReviewInput.approve());
+  }
+
+  protected void submit(Change change) throws Exception {
+    approve(change);
+    gApi.changes().id(change.getChangeId()).current().submit();
+  }
+
   /**
    * Generates a search query to test {@link com.google.gerrit.index.query.Matchable} implementation
    * of change {@link IndexPredicate}