Added flush

src/directory/directory.rs

@@ -205,6 +205,14 @@ pub trait Directory: DirectoryClone + fmt::Debug + Send + Sync + 'static {
     /// `OnCommit` `ReloadPolicy`. Not implementing watch in a `Directory` only prevents the
     /// `OnCommit` `ReloadPolicy` to work properly.
     fn watch(&self, watch_callback: WatchCallback) -> WatchHandle;
+
+    /// Ensure that all volatile files reach are persisted (in directory where that makes sense.)
+    ///
+    /// In order to make Near Real Time efficient, tantivy introduced the notion of soft_commit vs
+    /// commit. Commit will call `.flush()`, while softcommit won't.
+    fn flush(&self) -> io::Result<()> {
+        Ok(())
+    }
 }
 
 /// DirectoryClone

src/indexer/segment_updater.rs

@@ -296,14 +296,16 @@ impl SegmentUpdater {
                     // segment. However, we do not want to mark them as committed, and we want
                     // to keep the current set of committed segment.
                     segment_updater.0.segment_manager.soft_commit(opstamp, segment_entries);
-                    // ... obviously we do not save the meta file.
+                    // ... We do not save the meta file.
                 } else {
                     // Hard_commit. We register the new segment entries as committed.
                     segment_updater
                         .0
                         .segment_manager
                         .commit(opstamp, segment_entries);
+                    // TODO error handling.
                     segment_updater.save_metas(opstamp, payload);
+                    segment_updater.0.index.directory().flush().unwrap();
                 }
                 segment_updater.garbage_collect_files_exec();
                 segment_updater.consider_merge_options();