Index change asynchronously upon refs replicated event

Do not block the replication thread for performing a change
indexing, as it may slowdown the incoming operation on the
sender side.

When the refs are replicated through apply-object or sync
replication, the incoming thread is blocked until all listeners
are complete. The reindexing of a change may take a considerable
amount of time, especially when there are Prolog rules involved.

The ref is replicated therefore there is no need to block the
incoming operation waiting for the reindex to complete.

Change-Id: I49279262ea68bb6118ea76ff3123a7538dfe72fc

src/main/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandler.java

diff --git a/src/main/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandler.java b/src/main/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandler.java
index a618e16..9ee1e8e 100644
--- a/src/main/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandler.java
+++ b/src/main/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandler.java
@@ -52,7 +52,7 @@
           fetchRefReplicatedEvent.getRefName(), projectNameKey.get());
       Change.Id changeId = Change.Id.fromRef(fetchRefReplicatedEvent.getRefName());
       if (changeId != null) {
-        changeIndexer.index(projectNameKey, changeId);
+        changeIndexer.indexAsync(projectNameKey, changeId);
       } else {
         logger.atWarning().log(
             "Couldn't get changeId from refName. Skipping indexing of change %s for project %s",

src/test/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandlerTest.java

diff --git a/src/test/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandlerTest.java b/src/test/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandlerTest.java
index 81a4fc0..c4c35ed 100644
--- a/src/test/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandlerTest.java
+++ b/src/test/java/com/googlesource/gerrit/plugins/replication/pull/event/FetchRefReplicatedEventHandlerTest.java
@@ -58,7 +58,7 @@
               sourceUri,
               ReplicationState.RefFetchResult.SUCCEEDED,
               RefUpdate.Result.FAST_FORWARD));
-      verify(changeIndexerMock, times(1)).index(eq(projectNameKey), eq(changeId));
+      verify(changeIndexerMock, times(1)).indexAsync(eq(projectNameKey), eq(changeId));
     } finally {
       Context.unsetLocalEvent();
     }