This paper proposes a Tree-structured Database Machine (TDM), which is designed forsupporting large relational database systems. The TDM aims at totally improving three levelperformance bottlenecks in relational database systems, i.e.(?) data transfer bottleneck, dataprocessing bottleneck, and multiquery optimization bottleneck. For reducing these bottlenecks,the TDM provides the approaches of data partition and data distribution upon data storages forconcurrent data accesses, the tree-structured multiprocessor architecture for parallel dataprocessing, the technique of tightly-coupled-shared-memory for decreasing data movement,the mechanisms of indices and dictionaries for reducing data transfer from the data storages tothe memory, and so on. These features show that the TDM not only improves the systemperformance, increases the parallelism and the data processing power, but also eliminates theperformance bottlenecks in relational database systems. The TDM aims at totally improving three levelperformance bottlenecks in relational database systems, ie (?) Data transfer bottleneck, dataprocessing bottleneck, and multiquery optimization For reducing these bottlenecks, the TDM provides the methods of data partition and data distribution upon data storages for current data accesses, the tree-structured multiprocessor architecture for parallel dataprocessing, the technique of tightly-coupled-shared-memory for decreasing data movement, the mechanisms of indices and dictionaries for reducing data transfer from the data storages tothe memory, and so on. These features show that the TDM only only improves the system performance, increases the parallelism and the data processing power, but also eliminates the performance bottlenecks in relational database systems.