feat(db): add cache

Former-commit-id: 2dd8078d8df484ddac54379bc6c84c015c1fc530

cpp/src/db/FaissSerializer.cpp

 #include <easylogging++.h>
 #include <faiss/AutoTune.h>
 #include <wrapper/Index.h>
+#include <cache/CpuCacheMgr.h>
 
 #include "FaissSerializer.h"
 
@@ -33,6 +34,12 @@ Status FaissSerializer::Serialize() {
     return Status::OK();
 }
 
+Status FaissSerializer::Cache() {
+    zilliz::vecwise::cache::CpuCacheMgr::GetInstance(
+            )->InsertItem(location_, std::make_shared<Index>(pIndex_));
+
+    return Status::OK();
+}
 
 } // namespace engine
 } // namespace vecwise

cpp/src/db/FaissSerializer.h

@@ -24,6 +24,8 @@ public:
 
     virtual Status Serialize() override;
 
+    virtual Status Cache() override;
+
 protected:
     std::shared_ptr<faiss::Index> pIndex_;
     std::string location_;

cpp/src/db/Serializer.h

@@ -22,6 +22,8 @@ public:
 
     virtual Status Serialize() = 0;
 
+    virtual Status Cache() = 0;
+
     virtual ~Serializer() {}
 };