Item | Exclusive Hologres instance | Hologres Shared Cluster (Lakehouse Acceleration Edition) instance | Lightning |
Feature | Category | PostgreSQL 11 is supported. More operators can be obtained. | PostgreSQL 11 is supported. | PostgreSQL 8.2 is supported. |
Parameter optimization | Parameter optimization | Supported. For example, you can modify parameters related to databases or users based on your business requirements. | Supported. For example, you can modify parameters related to databases or users based on your business requirements. | Custom parameter optimization is not supported. For example, you cannot modify parameters based on time zones. |
Number of SQL connections or queries per second (QPS) | The number varies based on the instance type. You can execute the show max_connections statement to query the number of SQL connections. | The default number of SQL connections is 100. | The fixed number of SQL connections is 20. |
Data query based on foreign tables | Meta module loading | Data queries can be accelerated to respond within milliseconds. | Data queries can be accelerated to respond within sub-seconds. | The query response is slow, but the response speed increases linearly with the number of tables in a MaxCompute project. |
Data type | The basic data types, DECIMAL type in MaxCompute V2.0, DATETIME type, and ARRAY type are supported. | The basic data types, DECIMAL type in MaxCompute V2.0, DATETIME type, and ARRAY type are supported. | Only basic data types are supported. |
Engine optimization | N/A. | The query performance is much better than that of Lightning. | N/A. |
Data query based on internal tables | Supported indexes | Bitmap indexes and clustering keys are supported. | None. | None. |
Specified distribution keys | The distribution keys are specified to perform the Local Join or Local Group By operation. | None. | None. |
Resources | Computing resources and storage resources that you have purchased are exclusive to you. | Computing resources are shared, and storage resources are exclusive to you. | Computing resources are shared, and storage resources are exclusive to you. |