Allow to re-index in verbose mode during NoteDB migration

This makes it easier to see which changes just got indexed and
correlate performance graphs with what is going on.

Change-Id: Ic3131c997102bfd476326e84dba8cc7206592bbc

java/com/google/gerrit/pgm/MigrateToNoteDb.java

@@ -101,6 +101,9 @@ public class MigrateToNoteDb extends SiteProgram {
       handler = ExplicitBooleanOptionHandler.class)
   private Boolean reindex;
 
+  @Option(name = "--verbose", usage = "Output more detailed information when reindexing")
+  private boolean verbose;
+
   private Injector dbInjector;
   private Injector sysInjector;
   private LifecycleManager dbManager;
@@ -164,14 +167,18 @@ public class MigrateToNoteDb extends SiteProgram {
     }
     // Reindex all indices, to save the user from having to run yet another program by hand while
     // their server is offline.
-    List<String> reindexArgs =
-        ImmutableList.of(
+    ImmutableList.Builder<String> reindexArgsBuilder = ImmutableList.builder();
+    reindexArgsBuilder.add(
         "--site-path",
         getSitePath().toString(),
         "--threads",
         Integer.toString(threads),
         "--index",
         ChangeSchemaDefinitions.NAME);
+    if (verbose) {
+      reindexArgsBuilder.add("--verbose");
+    }
+    List<String> reindexArgs = reindexArgsBuilder.build();
     System.out.println("Migration complete, reindexing changes with:");
     System.out.println("  reindex " + reindexArgs.stream().collect(joining(" ")));
     Reindex reindexPgm = new Reindex();