This topic describes the benefits of the AliSQL kernel.
An instance in a dedicated cluster that runs the ApsaraDB RDS for MySQL database engine uses the same AliSQL kernel as a regular ApsaraDB RDS for MySQL instance and provides all features of a regular ApsaraDB RDS for MySQL instance. An instance in a dedicated cluster that runs the ApsaraDB RDS for MySQL database engine also provides advanced features such as enterprise-level security, backup, recovery, monitoring, performance optimization, and read-only instances. For more information, see Overview of AliSQL features and Introduction to X-Engine.
Features and MySQL versions
| Category | Feature | Description | MySQL 8.0 | MySQL 5.7 | MySQL 5.6 |
|---|---|---|---|---|---|
| Functionality | Native flashback | The native flashback feature allows you to query or restore the data at a specified point in time by executing SQL statements. This way, you can obtain the historical data at your earliest opportunity after accidental operations. | Supported | Not supported | Not supported |
| Thread Pool | The thread pool feature separates threads from sessions. If a large number of sessions are created on your RDS instance, ApsaraDB RDS can run a small number of threads to process the tasks in all active sessions. | Supported | Supported | Supported | |
| Statement outline | The statement outline feature allows ApsaraDB RDS to stably run query plans by using optimizer hints and index hints. You can install the DBMS_OUTLN package to use this feature. | Supported | Supported | Not supported | |
| Sequence Engine | The Sequence engine simplifies the generation of sequence values on your RDS instance. | Supported | Supported | Supported | |
| Returning | This returning feature allows DML statements to return result sets. You can install the DBMS_TRANS package to use this feature. | Supported | Not supported | Not supported | |
| Performance | Fast query cache | The fast query cache is a query cache that is developed by Alibaba Cloud based on the native MySQL query cache. The fast query cache uses a new design and a new implementation mechanism to increase the query performance of your RDS instance. | Not supported | Supported | Not supported |
| Binlog in Redo | The Binlog in Redo feature allows ApsaraDB RDS to write binary logs to the redo log file when transactions are committed. This reduces the operations on the disk and increases the performance of your RDS instance. | Supported | Not supported | Not supported | |
| Statement Queue | The statement queue feature allows statements to queue in the same bucket. These statements may be executed on the same resources. For example, these statements are executed on the same row of a table. This feature reduces the overheads that are caused by potential conflicts. | Supported | Supported | Not supported | |
| Inventory Hint | The inventory hint feature can be used in combination with the returning feature and the statement queue feature to commit and roll back transactions at fast speeds. This increases the throughput of your application. | Supported | Supported | Supported | |
| Stability | Faster DDL | The faster DDL feature provides an optimized buffer pool management mechanism. This mechanism reduces the impact of DDL operations on the performance of your RDS instance. This mechanism also increases the number of concurrent DDL operations that are allowed. | Supported | Supported | Supported |
| Statement concurrency control | The concurrency control (CCL) feature allows ApsaraDB RDS to control the concurrency of statements based on syntax rules. You can install the DBMS_CCL package to use this feature. | Supported | Supported | Not supported | |
| Performance Agent | The performance agent feature is provided as a plug-in for MySQL. This feature is used to calculate and analyze the performance metrics of your RDS instance. | Supported | Supported | Supported | |
| Purge Large File Asynchronously | The Purge Large File Asynchronously feature allows ApsaraDB RDS to asynchronously delete files from your RDS instance. This ensures the stability of your RDS instance. | Supported | Supported | Supported | |
| Performance Insight | The performance insight feature supports load monitoring, association analysis, and performance optimization at the instance level. You can evaluate the loads on your RDS instance and resolve performance issues. This increases the stability of your RDS instance. | Supported | Supported | Not supported | |
| Security | Recycle bin | The recycle bin feature allows ApsaraDB RDS to temporarily store deleted tables. It also allows you to specify a retention period within which you can retrieve the deleted tables. You can install the DBMS_RECYCLE package to use this feature. | Supported | Not supported | Not supported |