feat(db): add search api for db

Former-commit-id: 71e43c9b47c77b63968722d0595c97a474d33c9d

cpp/src/db/db.h

@@ -29,6 +29,9 @@ public:
     virtual Status add_vectors(const std::string& group_id_,
             size_t n, const float* vectors, IDNumbers& vector_ids_) = 0;
 
+    virtual Status search(const std::string& group_id, size_t k, size_t nq,
+            const float* vectors, QueryResults& results) = 0;
+
     DB() = default;
     DB(const DB&) = delete;
     DB& operator=(const DB&) = delete;

cpp/src/db/db_impl.cpp

@@ -52,6 +52,12 @@ Status DBImpl::add_vectors(const std::string& group_id_,
     }
 }
 
+Status DBImpl::search(const std::string& group_id, size_t k, size_t nq,
+        const float* vectors, QueryResults& results) {
+    // PXU TODO
+    return Status::OK();
+}
+
 void DBImpl::start_timer_task(int interval_) {
     std::thread bg_task(&DBImpl::background_timer_task, this, interval_);
     bg_task.detach();

cpp/src/db/db_impl.h

@@ -31,6 +31,9 @@ public:
     virtual Status add_vectors(const std::string& group_id_,
             size_t n, const float* vectors, IDNumbers& vector_ids_) override;
 
+    virtual Status search(const std::string& group_id, size_t k, size_t nq,
+            const float* vectors, QueryResults& results) override;
+
     virtual ~DBImpl();
 
 private:

cpp/src/db/types.h

@@ -10,6 +10,9 @@ typedef long IDNumber;
 typedef IDNumber* IDNumberPtr;
 typedef std::vector<IDNumber> IDNumbers;
 
+typedef std::vector<IDNumber> QueryResult;
+typedef std::vector<QueryResult> QueryResults;
+
 
 } // namespace engine
 } // namespace vecwise