diff --git a/be/src/olap/rowset/segment_v2/inverted_index_file_writer.cpp b/be/src/olap/rowset/segment_v2/inverted_index_file_writer.cpp
index d11b9fa54d0421..7a784a55b862d0 100644
--- a/be/src/olap/rowset/segment_v2/inverted_index_file_writer.cpp
+++ b/be/src/olap/rowset/segment_v2/inverted_index_file_writer.cpp
@@ -51,14 +51,26 @@ Result<DorisFSDirectory*> InvertedIndexFileWriter::open(const TabletIndex* index
 
     if (exists) {
         LOG(ERROR) << "try to init a directory:" << local_fs_index_path << " already exists";
-        return ResultError(Status::InternalError("init_fulltext_index directory already exists"));
+        return ResultError(
+                Status::InternalError("InvertedIndexFileWriter::open directory already exists"));
     }
 
     bool can_use_ram_dir = true;
     auto* dir = DorisFSDirectoryFactory::getDirectory(local_fs, local_fs_index_path.c_str(),
                                                       can_use_ram_dir);
-    _indices_dirs.emplace(std::make_pair(index_meta->index_id(), index_meta->get_index_suffix()),
-                          std::unique_ptr<DorisFSDirectory>(dir));
+    auto key = std::make_pair(index_meta->index_id(), index_meta->get_index_suffix());
+    auto [it, inserted] = _indices_dirs.emplace(key, std::unique_ptr<DorisFSDirectory>(dir));
+    if (!inserted) {
+        LOG(ERROR) << "InvertedIndexFileWriter::open attempted to insert a duplicate key: ("
+                   << key.first << ", " << key.second << ")";
+        LOG(ERROR) << "Directories already in map: ";
+        for (const auto& entry : _indices_dirs) {
+            LOG(ERROR) << "Key: (" << entry.first.first << ", " << entry.first.second << ")";
+        }
+        return ResultError(Status::InternalError(
+                "InvertedIndexFileWriter::open attempted to insert a duplicate dir"));
+    }
+
     return dir;
 }