1.适用于PolarDB的阿里云ApsaraDB：
它是与MySQL，PostgreSQL和Oracle兼容的云原生关系数据库。 ApsaraDB体系结构在单个群集中支持5000台物理机。它是为需要快速性能，高并发性和自动伸缩的关键业务数据库应用程序而设计的。
2.阿里云TSDB：
它是一个分布式的时间序列数据库。它是一种稳定，可靠且具有成本效益的在线高性能数据库服务。它提供有效的数据读写功能，高压缩比存储以及时序数据插值和聚合。
用于PolarDB的阿里云云数据库和阿里云TSDB之间的区别：
| S.NO. | Alibaba Cloud ApsaraDB for PolarDB | Alibaba Cloud TSDB |
|---|---|---|
| 1. | It was developed by Alibaba in August 2013. | It was developed by Alibaba. |
| 2. | It is a cloud-native relational database compatible with MySQL, PostgreSQL, and Oracle. | It is a stable, reliable, and cost-effective online high-performance time series database service. |
| 3. | In Alibaba Cloud ApsaraDB for PolarDB there are hosted server operating systems. | In Alibaba Cloud TSDB there are hosted server operating systems. |
| 4. | The license of Alibaba Cloud ApsaraDB for PolarDB is commercial. | The license of Alibaba Cloud TSDB is also commercial. |
| 5. | It supports XML format. | It does not support XML format. |
| 6. | It supports the Server-side scripting. | It does not support the Server-side scripting. |
| 7. | There is only one partitioning method – Sharding. | There are no partitioning methods. |
| 8. | It supports SQL query language. | It does not support SQL query language. |
| 9. | It supports replication methods. | It does not support replication methods. |
| 10. | ApsaraDB for PolarDB provides the concept of Referential Integrity. Hence, there are Foreign Keys. | TSDB does not provide the concept of Referential Integrity. Hence, no Foreign Keys. |
| 11. | It supports in-memory capabilities. | It does not support in-memory capabilities. |
| 12. | It does not offer any API for user-defined Map/Reduce methods. | It also does not offer any API for user-defined Map/Reduce methods. |
| 13. | It supports ACID properties. | It does not support ACID properties. |
| 14. | Programming languages supported are Java and Python. | Programming language supported is Java. |