ApsaraDB for SelectDB enforces limits on billing features, naming, cluster configuration, and connection protocols to ensure stable performance across all workloads.
Limits on features
The following limits apply based on billing method:
Pay-as-you-go instances
A pay-as-you-go instance can only contain pay-as-you-go clusters.
Each pay-as-you-go instance must retain at least one cluster. The last remaining cluster cannot be deleted.
Scheduled auto scaling is supported only for pay-as-you-go clusters.
Start and stop operations are supported only for pay-as-you-go clusters.
Subscription instances
A subscription instance can only contain subscription clusters. The expiration time of each cluster matches the expiration time of the instance.
Each subscription instance must retain at least one cluster. The last remaining cluster cannot be deleted.
Limits on names
| Item | Naming convention |
|---|---|
| Instance name | Length: 2–255 characters. Must start with a letter. Allowed characters: letters, digits, underscores (_), and hyphens (-). |
| Cluster name | Length: up to 64 characters. Must start with a letter. Not case-sensitive. Allowed characters: letters, digits, and underscores (_). Consecutive underscores are not allowed. |
| Password | Length: 8–32 characters. Must contain at least three of the following character types: uppercase letters, lowercase letters, digits, and special characters (! @ # $ % ^ & * ( ) _ + - =). |
Limits on purchasing and configuring a cluster
| Item | Default limit |
|---|---|
| Computing resources | 4–1,024 vCPUs per cluster. Memory is four times the vCPU count (GB). |
| Cache size | Minimum: 100 GB for clusters with 4, 8, or 16 vCPUs; 100 × (vCPUs / 32) GB for clusters with 64 or more vCPUs. Maximum: 500 × vCPUs GB. |
Limits on connection protocols
The database connector of your application or client must be compatible with MySQL 5.7.