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TiDB Serverless FAQs |
Learn about the most frequently asked questions (FAQs) relating to TiDB Serverless. |
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This document lists the most frequently asked questions about TiDB Serverless.
TiDB Serverless offers the TiDB database with full HTAP capabilities for you and your organization. It is a fully managed, auto-scaling deployment of TiDB that lets you start using your database immediately, develop and run your application without caring about the underlying nodes, and automatically scale based on your application's workload changes.
Get started with the 5-minute TiDB Cloud Quick Start.
For each organization in TiDB Cloud, you can create a maximum of five TiDB Serverless clusters by default. To create more TiDB Serverless clusters, you need to add a credit card and set a spending limit for usage.
Some of TiDB Cloud features are partially supported or not supported on TiDB Serverless. For more information, see TiDB Serverless Limitations and Quotas.
When will TiDB serverless be available on cloud platforms other than AWS, such as Google Cloud or Azure?
We are actively working on expanding TiDB Serverless to other cloud platforms, including Google Cloud and Azure. However, we do not have an exact timeline for now as we currently focus on filling gaps and ensuring seamless functionality across all environments. Rest assured, we are working hard to make TiDB Serverless available on more cloud platforms, and we will keep our community updated as we progress.
I created a Developer Tier cluster before TiDB Serverless was available. Can I still use my cluster?
Yes, your Developer Tier cluster has been automatically migrated to the TiDB Serverless cluster, providing you with an improved user experience without any disruptions to your prior usage.
TiDB Serverless adopts a pay-as-you-go model, meaning that you only pay for the storage space and cluster usage. In this model, all cluster activities such as SQL queries, bulk operations, and background jobs are quantified in Request Units (RUs). RU is an abstract measurement for the size and intricacy of requests initiated on your cluster. For more information, see TiDB Serverless Pricing Details.
For the first five TiDB Serverless clusters in your organization, TiDB Cloud provides a free usage quota for each of them as follows:
- Row-based storage: 5 GiB
- Request Units (RUs): 50 million RUs per month
Usage beyond the free quota will be charged. Once the free quota of a cluster is reached, the read and write operations on this cluster will be throttled until you increase the quota or the usage is reset upon the start of a new month.
For more information, see TiDB Serverless usage quota.
Under the free plan, cluster performance is capped at a maximum of 10,000 RUs per second based on actual workload. Additionally, memory allocation per query is limited to 256 MiB. To maximize cluster performance, you can choose to enable the commercial offering by increasing your spending limit.
To get the RU consumption of individual SQL statements, you can use the EXPLAIN ANALYZE SQL statement. However, it is important to note that the RUs usage returned in EXPLAIN ANALYZE does not incorporate egress RUs, as egress usage is measured separately in the gateway, which is unknown to the TiDB server.
To get the RUs and storage used by your cluster, view the Usage this month pane on your cluster overview page. With your past resource usage data and real-time resource usage in this pane, you can track your cluster's resource consumption and estimate a reasonable spending limit. If the free quota cannot meet your requirement, you can edit the spending limit easily. For more information, see Manage Spending Limit for TiDB Serverless clusters.
Ensure that your queries have been carefully optimized for optimal performance by following the guidelines in Optimizing SQL Performance. In addition, minimizing the amount of egress traffic is also crucial for reducing RUs consumption. To achieve this, it is recommended to return only the necessary columns and rows in your query, which in turn helps reduce network egress traffic. This can be achieved by carefully selecting and filtering the columns and rows to be returned, thereby optimizing network utilization.
The storage is metered based on the amount of data stored in a TiDB Serverless cluster, measured in GiB per month. It is calculated by multiplying the total size of all the tables and indexes (excluding data compression or replicas) with the number of hours the data is stored in that month.
This is because TiDB retains dropped tables and databases for a certain period of time. This retention period ensures that transactions dependent on these tables can continue execution without disruption. Additionally, the retention period makes the FLASHBACK TABLE/FLASHBACK DATABASE feature feasible, which allows you to recover dropped tables and databases if they were mistakenly deleted.
RU consumptions can occur in various scenarios. One common scenario is during background queries, such as synchronizing schema changes between TiDB instances. Another scenario is when certain web console features generate queries, like loading schemas. These processes use RUs even without explicit user triggers.
A spike in RU usage can occur due to necessary background jobs in TiDB. These jobs, such as automatically analyzing tables and rebuilding statistics, are required for generating optimized query plans.
Once a cluster reaches its free quota or spending limit, the cluster will enforce throttling measures on its read and write operations. These operations will be limited until the quota is increased or the usage is reset at the start of a new month. For more information, see TiDB Serverless Limitations and Quotas.
The serverless technology is designed for multi-tenancy and the resources used by all clusters are shared. To get managed TiDB service with isolated infrastructure and resources, you can upgrade it to TiDB Dedicated.
- Your connections are encrypted by Transport Layer Security (TLS). For more information about using TLS to connect to TiDB Serverless, see TLS Connection to TiDB Serverless.
- All persisted data on TiDB Serverless is encrypted-at-rest using the tool of the cloud provider that your cluster is running in.
No. TiDB Serverless clusters are upgraded automatically as we roll out new TiDB versions on TiDB Cloud. You can see what version of TiDB your cluster is running in the TiDB Cloud console or in the latest release note. Alternatively, you can also connect to your cluster and use SELECT version() or SELECT tidb_version() to check the TiDB version.