TencentDB for SQL Server service only offers instances with bundled licenses, meaning that upon creation, each instance is endowed with the corresponding version's Microsoft SQL Server software licensing authorization. It does not support the provision of licenses brought by users themselves.
In order to ensure the stability and security of instances, TencentDB for SQL Server has certain restrictions on usage as detailed below.
TencentDB for SQL Server instances are available in three editions: single-node (formerly Basic Edition), two-node (formerly HA/Cluster Edition), and multi-node. Each edition has different features. For details, see Features and Differences.
Note:
TencentDB for SQL Server does not support access to external applications through the database instance; it only permits access to the database instance via external applications.
If you have other questions about usage restrictions, submit a ticket for assistance.
If the instance only has one CPU core, we recommend that you keep the database quantity limit at 70 to guarantee instance stability.
The maximum number of databases that can be created for instances of different specifications is related to the value of the max worker threads parameter. If the parameter uses the default value of 0, the maximum number of databases that can be created for instances of different versions and specifications is 80. If the value of this parameter is set to 20000 or higher, the maximum number of databases that can be created for instances of different versions and specifications is related to the number of CPU cores of an instance. You can refer to the calculation formula below. For information on how to set the parameters, see Setting Instance Parameters.
SQL Server 2008 R2 Enterprise instances don't support lifting the database quantity limit, which is 70. The limit in other SQL Server instances is subject to the number of instance CPU cores as calculated below:
Multi-node
2017 Enterprise
2019 Enterprise
2022 Enterprise
The maximum number of databases is related to the instance CPUs. For instances with 4 or fewer CPU cores, the maximum number of databases is 80. For instances with 8 or more CPU cores, the maximum number of databases is 100.
Two-node (formerly High Availability Edition)
2012 Standard/Enterprise
2014 Standard/Enterprise
2016 Standard/Enterprise
Maximum number of databases:
Extract the square root of the CPU core quantity, round it to one decimal place, multiply the result by 40, and add the product to 80 to get the value X. The smaller value between X and 300 is the maximum number of databases. For example, you can create up to 160 databases in a 4-core 16 GB MEM SQL Server 2014 Enterprise instance.
The maximum number of databases is related to the instance CPU. The maximum number of databases for instances with 8-core CPU or less is 80, and the maximum number of databases for instances with 8-core CPU or above is 100.
Extract the square root of the CPU core quantity, round it down to the nearest integer, and multiply the result by 100 to get the value N. The smaller value between N and 400 is the maximum number of databases. For example, you can create up to 200 databases in a 4-core 16 GB MEM SQL Server 2017 Enterprise instance.
Table of instance CPU core quantity and corresponding database quantity limit
Database quantity limit for single-node edition (formerly Basic Edition)
Database quantity limit for two-node edition (formerly High Availability/Cluster Edition)
Linked servers are not supported between other clouds or self-built environments and Tencent Cloud and are only supported for a Tencent Cloud private network. However, within the TencentDB for SQL Server instance architecture, there are the following restrictions:
1. Cross-Architecture Scenarios
Cross-Architecture Direction
Description
Two-node instance → single-node instance
Not supported.
Single-node instance → two-node instance
Not supported.
Local disk instance → cloud disk instance
Not supported.
Cloud disk instance → local disk instance
Not supported.
2. Between Two-Node Instances
Cross-Architecture Direction
Description
Two-node local disk instance → two-node local disk instance
Interconnection is supported between domestic regions, and interconnection is supported between overseas regions, but not between domestic and overseas regions.
Two-node cloud disk instance → two-node cloud disk instance
Only interconnection within the same region is supported.
3. Between Single Node Instances
Interconnection is supported only when the source and target are the same instance.
