implemented the first version of statement_cache

backends/postgres/include/postgres_statement.hpp

@@ -12,7 +12,7 @@ namespace matador::backends::postgres {
 class postgres_statement final : public sql::statement_impl
 {
 public:
-  postgres_statement(PGconn *db, PGresult *result, std::string name, const sql::query_context &query);
+  postgres_statement(PGconn *db, std::string name, const sql::query_context &query);
 
   utils::result<size_t, utils::error> execute() override;
   utils::result<std::unique_ptr<sql::query_result_impl>, utils::error> fetch() override;
@@ -22,7 +22,6 @@ protected:
 
 private:
   PGconn *db_{nullptr};
-  PGresult *result_{nullptr};
 
   std::string name_;
 

backends/postgres/src/postgres_connection.cpp

@@ -132,7 +132,7 @@ utils::result<std::unique_ptr<sql::statement_impl>, utils::error> postgres_conne
     return utils::failure(make_error(sql::error_code::PREPARE_FAILED, result, conn_, "Failed to prepare", context.sql));
   }
 
-  std::unique_ptr<sql::statement_impl> s(std::make_unique<postgres_statement>(conn_, result, statement_name, context));
+  std::unique_ptr<sql::statement_impl> s(std::make_unique<postgres_statement>(conn_, statement_name, context));
   return utils::ok(std::move(s));
 }
 

backends/postgres/src/postgres_statement.cpp

@@ -4,10 +4,9 @@
 
 namespace matador::backends::postgres {
 
-postgres_statement::postgres_statement(PGconn *db, PGresult *result, std::string name, const sql::query_context &query)
+postgres_statement::postgres_statement(PGconn *db, std::string name, const sql::query_context &query)
 : statement_impl(query)
 , db_(db)
-, result_(result)
 , name_(std::move(name))
 , binder_(query_.bind_vars.size())
 {}