diff --git a/cpp/src/db/DBImpl.cpp b/cpp/src/db/DBImpl.cpp
index 19c708dd0b530a02e1a917d61bc6c544d758a515..2fc8e9040078af26f68d635f838be3389002e832 100644
--- a/cpp/src/db/DBImpl.cpp
+++ b/cpp/src/db/DBImpl.cpp
@@ -89,6 +89,7 @@ Status DBImpl::search(const std::string &group_id, size_t k, size_t nq,
         index->add_with_ids(file_index->ntotal,
                             dynamic_cast<faiss::IndexFlat *>(file_index->index)->xb.data(),
                             file_index->id_map.data());
+        delete file_index;
     }
 
     {
@@ -220,6 +221,7 @@ Status DBImpl::merge_files(const std::string& group_id, const meta::DateT& date,
         updated.push_back(file_schema);
         LOG(DEBUG) << "About to merge file " << file_schema.file_id <<
             " of size=" << file_schema.rows;
+        delete file_index;
     }
 
     auto index_size = group_file.dimension * index->ntotal;
@@ -301,6 +303,8 @@ Status DBImpl::build_index(const meta::GroupFileSchema& file) {
     meta::GroupFilesSchema update_files = {to_remove, group_file};
     _pMeta->update_files(update_files);
 
+    delete from_index;
+
     return Status::OK();
 }
 
diff --git a/cpp/src/db/MemManager.cpp b/cpp/src/db/MemManager.cpp
index 59ae4fd19b71e45127ede17f7197a4539fccc0fe..d1097f40724933362412213fae381b553a69d8c3 100644
--- a/cpp/src/db/MemManager.cpp
+++ b/cpp/src/db/MemManager.cpp
@@ -47,7 +47,7 @@ Status MemVectors::serialize(std::string& group_id) {
     /* faiss::write_index(pIndex_, _file_location.c_str()); */
     group_id = schema_.group_id;
     auto rows = approximate_size();
-    write_index(pIndex_, schema_.location.c_str());
+    write_index(pIndex_.get(), schema_.location.c_str());
     schema_.rows = rows;
     schema_.file_type = (rows >= options_.index_trigger_size) ?
         meta::GroupFileSchema::TO_INDEX : meta::GroupFileSchema::RAW;
@@ -61,10 +61,6 @@ MemVectors::~MemVectors() {
         delete _pIdGenerator;
         _pIdGenerator = nullptr;
     }
-    if (pIndex_ != nullptr) {
-        delete pIndex_;
-        pIndex_ = nullptr;
-    }
 }
 
 /*
diff --git a/cpp/src/db/MemManager.h b/cpp/src/db/MemManager.h
index a87c54c14ee960d94b5fca939c74bc696252167b..c99e2be3c1ddd84077059fd009827b2a74b144ff 100644
--- a/cpp/src/db/MemManager.h
+++ b/cpp/src/db/MemManager.h
@@ -49,7 +49,7 @@ private:
     Options options_;
     meta::GroupFileSchema schema_;
     IDGenerator* _pIdGenerator;
-    faiss::Index* pIndex_;
+    std::shared_ptr<faiss::Index> pIndex_;
 
 }; // MemVectors