The OPTIMIZED linked database feature is a specific SAP HANA capability designed for efficient cross-database queries exclusively between SAP HANA systems. Its primary characteristic is simplifying data access by eliminating the need for virtual tables, which are required by the more general Smart Data Access (SDA) feature. Instead, users can directly query remote objects using a three-part naming convention: ... This direct access, combined with the homogeneous HANA-to-HANA landscape, allows the query optimizer on the target (local) system to have full knowledge of the remote database's objects and statistics, leading to highly optimized execution plans.

A. While metadata caching is used to achieve optimization, the more fundamental characteristics are the feature's scope (HANA-to-HANA) and its unique syntax, which enable these optimizations.

B. The Linked Database feature is explicitly designed to avoid the creation of virtual tables (hidden or otherwise), which is its main simplification compared to standard Smart Data Access (SDA).

1. SAP HANA Cloud

SAP HANA Database Administration Guide

Section: "Linked Database".

This guide states

"Linked database is a feature for executing cross-database SELECT queries between SAP HANA databases." This directly supports option C.

It also specifies the access method: "Instead

you can directly access tables in the remote database using the syntax ..." This directly supports option D and refutes option B.

2. SAP Note 2919784 - FAQ: SAP HANA Linked Database

Version 4

Published 2023-08-08.

The note's answer to "What is Linked Database?" reiterates that it is for "cross-database SELECT queries between SAP HANA databases" (C) and that "Instead of creating virtual tables for remote tables

you can directly access tables in the remote database using the syntax..." (D)

which explicitly contradicts B.

3. SAP HANA Platform 2.0 SPS 07

SAP HANA Administration Guide for SAP HANA Platform

Section: "2.10.3 Linked Database".

This document describes Linked Database as a "simplified alternative to Smart Data Access for HANA-to-HANA scenarios" (C). It also highlights the benefit that "No virtual tables are required on the local database" (refutes B). The optimizer's "full knowledge" is mentioned as the key to optimization

which is enabled by the HANA-to-HANA context.