diff --git a/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java b/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
index e56f470..44a377a 100644
--- a/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
+++ b/java/com/google/gerrit/elasticsearch/AbstractElasticIndex.java
@@ -84,6 +84,9 @@
   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";
 
@@ -288,7 +291,7 @@
 
   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);
diff --git a/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java b/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
index 625a598..162654d 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticChangeIndex.java
@@ -37,6 +37,7 @@
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.index.FieldDef;
 import com.google.gerrit.index.QueryOptions;
+import com.google.gerrit.index.RefState;
 import com.google.gerrit.index.Schema;
 import com.google.gerrit.index.query.DataSource;
 import com.google.gerrit.index.query.Predicate;
@@ -57,6 +58,9 @@
 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.Optional;
 import java.util.Set;
@@ -133,14 +137,24 @@
 
   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;
+  }
+
   @Override
   protected String getDeleteActions(Change.Id c) {
     return getDeleteRequest(c);
@@ -341,7 +355,7 @@
 
     // Ref-state.
     if (fields.contains(ChangeField.REF_STATE.getName())) {
-      cd.setRefStates(getByteArray(source, ChangeField.REF_STATE.getName()));
+      cd.setRefStates(RefState.parseStates(getByteArray(source, ChangeField.REF_STATE.getName())));
     }
 
     // Ref-state-pattern.
@@ -361,6 +375,10 @@
           cd);
     }
 
+    if (fields.contains(ChangeField.MERGED_ON.getName())) {
+      decodeMergedOn(source, cd);
+    }
+
     return cd;
   }
 
@@ -396,4 +414,18 @@
     }
     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);
+  }
 }
diff --git a/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java b/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
index 06b128c..c443529 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticConfiguration.java
@@ -26,8 +26,10 @@
 import java.net.URISyntaxException;
 import java.util.ArrayList;
 import java.util.List;
+import java.util.concurrent.TimeUnit;
 import org.apache.http.HttpHost;
 import org.eclipse.jgit.lib.Config;
+import org.elasticsearch.client.RestClientBuilder;
 
 @Singleton
 class ElasticConfiguration {
@@ -41,12 +43,16 @@
   static final String KEY_NUMBER_OF_SHARDS = "numberOfShards";
   static final String KEY_NUMBER_OF_REPLICAS = "numberOfReplicas";
   static final String KEY_MAX_RESULT_WINDOW = "maxResultWindow";
+  static final String KEY_CONNECT_TIMEOUT = "connectTimeout";
+  static final String KEY_SOCKET_TIMEOUT = "socketTimeout";
 
   static final String DEFAULT_PORT = "9200";
   static final String DEFAULT_USERNAME = "elastic";
   static final int DEFAULT_NUMBER_OF_SHARDS = 1;
   static final int DEFAULT_NUMBER_OF_REPLICAS = 1;
   static final int DEFAULT_MAX_RESULT_WINDOW = 10000;
+  static final int DEFAULT_CONNECT_TIMEOUT = RestClientBuilder.DEFAULT_CONNECT_TIMEOUT_MILLIS;
+  static final int DEFAULT_SOCKET_TIMEOUT = RestClientBuilder.DEFAULT_SOCKET_TIMEOUT_MILLIS;
 
   private final Config cfg;
   private final List<HttpHost> hosts;
@@ -56,6 +62,8 @@
   final int numberOfShards;
   final int numberOfReplicas;
   final int maxResultWindow;
+  final int connectTimeout;
+  final int socketTimeout;
   final String prefix;
 
   @Inject
@@ -74,6 +82,22 @@
         cfg.getInt(SECTION_ELASTICSEARCH, null, KEY_NUMBER_OF_REPLICAS, DEFAULT_NUMBER_OF_REPLICAS);
     this.maxResultWindow =
         cfg.getInt(SECTION_ELASTICSEARCH, null, KEY_MAX_RESULT_WINDOW, DEFAULT_MAX_RESULT_WINDOW);
+    this.connectTimeout =
+        (int)
+            cfg.getTimeUnit(
+                SECTION_ELASTICSEARCH,
+                null,
+                KEY_CONNECT_TIMEOUT,
+                DEFAULT_CONNECT_TIMEOUT,
+                TimeUnit.MILLISECONDS);
+    this.socketTimeout =
+        (int)
+            cfg.getTimeUnit(
+                SECTION_ELASTICSEARCH,
+                null,
+                KEY_SOCKET_TIMEOUT,
+                DEFAULT_SOCKET_TIMEOUT,
+                TimeUnit.MILLISECONDS);
     this.hosts = new ArrayList<>();
     for (String server : cfg.getStringList(SECTION_ELASTICSEARCH, null, KEY_SERVER)) {
       try {
diff --git a/java/com/google/gerrit/elasticsearch/ElasticGroupIndex.java b/java/com/google/gerrit/elasticsearch/ElasticGroupIndex.java
index f8c2ec5..781ed43 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticGroupIndex.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticGroupIndex.java
@@ -20,6 +20,7 @@
 import com.google.gerrit.elasticsearch.bulk.IndexRequest;
 import com.google.gerrit.elasticsearch.bulk.UpdateRequest;
 import com.google.gerrit.entities.AccountGroup;
+import com.google.gerrit.entities.InternalGroup;
 import com.google.gerrit.exceptions.StorageException;
 import com.google.gerrit.index.QueryOptions;
 import com.google.gerrit.index.Schema;
@@ -28,7 +29,6 @@
 import com.google.gerrit.index.query.QueryParseException;
 import com.google.gerrit.server.account.GroupCache;
 import com.google.gerrit.server.config.SitePaths;
-import com.google.gerrit.server.group.InternalGroup;
 import com.google.gerrit.server.index.IndexUtils;
 import com.google.gerrit.server.index.group.GroupField;
 import com.google.gerrit.server.index.group.GroupIndex;
diff --git a/java/com/google/gerrit/elasticsearch/ElasticMapping.java b/java/com/google/gerrit/elasticsearch/ElasticMapping.java
index f8c4168..edd05c9 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticMapping.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticMapping.java
@@ -21,6 +21,10 @@
 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 @@
     }
 
     Builder addTimestamp(String name) {
-      FieldProperties properties = new FieldProperties("date");
-      properties.type = "date";
-      properties.format = "dateOptionalTime";
+      FieldProperties properties = new FieldProperties(TIMESTAMP_FIELD_TYPE);
+      properties.type = TIMESTAMP_FIELD_TYPE;
+      properties.format = TIMESTAMP_FIELD_FORMAT;
       fields.put(name, properties);
       return this;
     }
diff --git a/java/com/google/gerrit/elasticsearch/ElasticQueryBuilder.java b/java/com/google/gerrit/elasticsearch/ElasticQueryBuilder.java
index d05e91c..40ac603 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticQueryBuilder.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticQueryBuilder.java
@@ -29,7 +29,6 @@
 import com.google.gerrit.index.query.QueryParseException;
 import com.google.gerrit.index.query.RegexPredicate;
 import com.google.gerrit.index.query.TimestampRangePredicate;
-import com.google.gerrit.server.query.change.AfterPredicate;
 import java.time.Instant;
 
 public class ElasticQueryBuilder {
@@ -130,7 +129,9 @@
   private <T> QueryBuilder timestampQuery(IndexPredicate<T> p) throws QueryParseException {
     if (p instanceof TimestampRangePredicate) {
       TimestampRangePredicate<T> r = (TimestampRangePredicate<T>) p;
-      if (p instanceof AfterPredicate) {
+      if (r.getMaxTimestamp().getTime() == Long.MAX_VALUE) {
+        // The time range only has the start value, search from the start to the max supported value
+        // Long.MAX_VALUE
         return QueryBuilders.rangeQuery(r.getField().getName())
             .gte(Instant.ofEpochMilli(r.getMinTimestamp().getTime()));
       }
diff --git a/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java b/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
index f635b23..b41f365 100644
--- a/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
+++ b/java/com/google/gerrit/elasticsearch/ElasticRestClientProvider.java
@@ -27,6 +27,7 @@
 import org.apache.http.auth.AuthScope;
 import org.apache.http.auth.UsernamePasswordCredentials;
 import org.apache.http.client.CredentialsProvider;
+import org.apache.http.client.config.RequestConfig;
 import org.apache.http.impl.client.BasicCredentialsProvider;
 import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
 import org.elasticsearch.client.Request;
@@ -128,10 +129,19 @@
 
   private RestClient build() {
     RestClientBuilder builder = RestClient.builder(cfg.getHosts());
+    setConfiguredTimeouts(builder);
     setConfiguredCredentialsIfAny(builder);
     return builder.build();
   }
 
+  private void setConfiguredTimeouts(RestClientBuilder builder) {
+    builder.setRequestConfigCallback(
+        (RequestConfig.Builder requestConfigBuilder) ->
+            requestConfigBuilder
+                .setConnectTimeout(cfg.connectTimeout)
+                .setSocketTimeout(cfg.socketTimeout));
+  }
+
   private void setConfiguredCredentialsIfAny(RestClientBuilder builder) {
     String username = cfg.username;
     String password = cfg.password;
diff --git a/javatests/com/google/gerrit/elasticsearch/BUILD b/javatests/com/google/gerrit/elasticsearch/BUILD
index be35d5a..3036811 100644
--- a/javatests/com/google/gerrit/elasticsearch/BUILD
+++ b/javatests/com/google/gerrit/elasticsearch/BUILD
@@ -55,7 +55,6 @@
 ELASTICSEARCH_TAGS = [
     "docker",
     "elastic",
-    "exclusive",
 ]
 
 [junit_tests(