This topic describes the limits that apply to Hologres.
Limits on data query in MaxCompute tables
- Hologres can scan a maximum of 50 partitions from a partitioned table during a single query.
- The maximum amount of underlying data scanned for each query is 200 GB, regardless of the number of tables and fields.
Limits on UDFs
- Hologres does not support user-defined functions (UDFs) that are created in MaxCompute.
- Hologres does not allow you to create or use PostgreSQL UDFs. However, you can use the built-in functions of PostgreSQL.
- Hologres does not support the built-in functions of MaxCompute.
Limits on the number of connections
Limits on data types
The data types of Hologres and PostgreSQL are compatible. However, the data types of Hologres are a subset of the data types of PostgreSQL. For more information, see Data types.
Limits on the purchase of Hologres instances
- Each Alibaba Cloud account can buy a maximum of three instances per day.
- Hologres supports the pay-as-you-go and subscription billing methods. You can only change the billing method from pay-as-you-go to subscription. You cannot change the billing method from subscription to pay-as-you-go.
- If you stop the instance that uses the pay-as-you-go billing method in the Hologres console, you are still charged for the storage resources of the instance.
- If you are using the subscription billing method and the quota of the storage resources is reached, the billing method is changed to pay-as-you-go.