fix data flush

Signed-off-by: dentiny <[email protected]>

src/ray/util/pipe_logger.cc

@@ -156,9 +156,18 @@ RedirectionFileHandle OpenFileForRedirection(const std::string &file_path) {
   auto ostream =
       std::make_shared<boost::iostreams::stream<boost::iostreams::file_descriptor_sink>>(
           std::move(sink));
-  auto flush_fn = [ostream]() { ostream->flush(); };
-  auto close_fn = [ostream]() {
+  auto flush_fn = [ostream, handle]() {
+    // Flush stream internal buffer to fd.
     ostream->flush();
+// Flush file handle.
+#if defined(__APPLE__) || defined(__linux__)
+    RAY_CHECK_EQ(fdatasync(handle), 0);
+#elif defined(_WIN32)
+    RAY_CHECK_EQ(FlushFileBuffers(handle));
+#endif
+  };
+  auto close_fn = [flush_fn, ostream]() {
+    flush_fn();
     ostream->close();
   };
   return RedirectionFileHandle{