Limitations
This page covers key constraints and limits for Hologres, including MaxCompute direct query limits, user-defined function (UDF) support, data type compatibility, HoloStudio workspace limits, and billing limits. For limits not listed here, refer to the documentation for each individual feature.
Some limits are fixed; others have been removed in specific versions. For more information, contact technical support.
Limits on direct queries to MaxCompute
Limit | Value | Adjustable | Notes |
Maximum partitions scanned per query on a partitioned table | 512 | No | Removed in Hologres V3.0.20 and later |
Maximum underlying data scanned per query | 200 GB | No | Applies regardless of the number of tables or fields. Removed in Hologres V3.0.20 and later. |
MaxCompute built-in functions | Not supported | No | Use PostgreSQL built-in functions as an alternative |
UDF limits
Hologres does not support user-defined functions (UDFs) created in MaxCompute, and you cannot create or define UDFs directly in Hologres. As an alternative, Hologres supports the PostgreSQL built-in functions, which cover most common data transformation and aggregation needs.
Data type constraints
Hologres is compatible with the PostgreSQL ecosystem and supports a subset of PostgreSQL data types. For the full list of supported types, see Data types.
HoloStudio limits
HoloStudio is being upgraded to DataStudio. Use DataStudio or HoloWeb for development, as they provide more features and a better experience. For details, see DataWorks HoloStudio unpublishing announcement.
An instance can have multiple databases. A single database can be attached to multiple HoloStudio workspaces in the same region.
The Go to DataWorks for Scheduling operation uses the public resource group by default. To use a dedicated resource group, contact technical support or join the Hologres DingTalk group. For details, see How do I get more online support?
Purchase and billing limits
Limit | Value | Adjustable | Notes |
Maximum instances purchased per Alibaba Cloud account per day | 3 | No | Fixed |
Supported billing methods | Subscription, Pay-as-you-go | — | — |
Convert pay-as-you-go to subscription | Supported | — | — |
Convert subscription to pay-as-you-go | Supported | — | — |
Billing when a Pay-as-you-go instance is manually stopped | Computing billing stops; storage billing continues | — | Storage is billed until the instance is deleted |
Storage billing for subscription instances that exceed the purchased quota | Billed on a Pay-as-you-go basis | — | Only the excess storage is billed at the Pay-as-you-go rate |