Update TiDB Serverless FAQ (#14100)

TOC-tidb-cloud.md

@@ -95,7 +95,7 @@
       - [Connection Method Overview](/tidb-cloud/connect-to-tidb-cluster-serverless.md)
       - [Connect via Public Endpoint](/tidb-cloud/connect-via-standard-connection-serverless.md)
       - [Connect via Private Endpoint](/tidb-cloud/set-up-private-endpoint-connections-serverless.md)
-    - [Manage Spend Limit](/tidb-cloud/manage-serverless-spend-limit.md)
+    - [Manage Spending Limit](/tidb-cloud/manage-serverless-spend-limit.md)
     - [Back Up and Restore TiDB Serverless Data](/tidb-cloud/backup-and-restore-serverless.md)
   - Manage TiDB Dedicated Clusters
     - [Create a TiDB Dedicated Cluster](/tidb-cloud/create-tidb-cluster.md)

tidb-cloud/create-tidb-cluster-serverless.md

@@ -31,11 +31,11 @@ To create a TiDB Serverless cluster, take the following steps:
 
 4. The cloud provider of TiDB Serverless is AWS. You can select an AWS region where you want to host your cluster.
 
-5. (Optional) Change the spend limit if you plan to use more storage and compute resources than the [free quota](/tidb-cloud/select-cluster-tier.md#usage-quota). If you have not added a payment method, you need to add a credit card after editing the limit.
+5. (Optional) Change the spending limit if you plan to use more storage and compute resources than the [free quota](/tidb-cloud/select-cluster-tier.md#usage-quota). If you have not added a payment method, you need to add a credit card after editing the limit.
 
     > **Note:**
     >
-    > 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 [spend limit](/tidb-cloud/tidb-cloud-glossary.md#spend-limit) for the usage.
+    > 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](/tidb-cloud/tidb-cloud-glossary.md#spending-limit) for the usage.
 
 6. Update the default cluster name if necessary, and then click **Create**.
 

tidb-cloud/manage-serverless-spend-limit.md

@@ -1,17 +1,17 @@
 ---
-title: Manage Spend Limit for TiDB Serverless clusters
-summary: Learn how to manage spend limit for your TiDB Serverless clusters.
+title: Manage Spending Limit for TiDB Serverless clusters
+summary: Learn how to manage spending limit for your TiDB Serverless clusters.
 ---
 
-# Manage Spend Limit for TiDB Serverless Clusters
+# Manage Spending Limit for TiDB Serverless Clusters
 
 > **Note:**
 >
-> The spend limit is only applicable to TiDB Serverless clusters.
+> The spending limit is only applicable to TiDB Serverless clusters.
 
-Spend limit refers to the maximum amount of money that you are willing to spend on a particular workload in a month. It is a cost-control mechanism that allows you to set a budget for your TiDB Serverless clusters.
+Spending limit refers to the maximum amount of money that you are willing to spend on a particular workload in a month. It is a cost-control mechanism that allows you to set a budget for your TiDB Serverless clusters.
 
-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 spend limit for the usage. But if you delete some of your previous clusters before creating more, the new cluster can still be created without a credit card.
+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 the usage. But if you delete some of your previous clusters before creating more, the new cluster can still be created without a credit card.
 
 ## Usage quota
 
@@ -20,15 +20,15 @@ For the first five TiDB Serverless clusters in your organization, TiDB Cloud pro
 - Row-based storage: 5 GiB
 - [Request Units (RUs)](/tidb-cloud/tidb-cloud-glossary.md#request-unit): 50 million RUs per month
 
-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](#update-spend-limit) or the usage is reset upon the start of a new month. For example, when the storage of a cluster exceeds 5 GiB, the maximum size limit of a single transaction is reduced from 10 MiB to 1 MiB.
+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](#update-spending-limit) or the usage is reset upon the start of a new month. For example, when the storage of a cluster exceeds 5 GiB, the maximum size limit of a single transaction is reduced from 10 MiB to 1 MiB.
 
 To learn more about the RU consumption of different resources (including read, write, SQL CPU, and network egress), the pricing details, and the throttled information, see [TiDB Serverless Pricing Details](https://www.pingcap.com/tidb-cloud-serverless-pricing-details).
 
-If you want to create a TiDB Serverless cluster with an additional quota, you can edit the spend limit on the cluster creation page. For more information, see [Create a TiDB Serverless cluster](/tidb-cloud/create-tidb-cluster-serverless.md).
+If you want to create a TiDB Serverless cluster with an additional quota, you can edit the spending limit on the cluster creation page. For more information, see [Create a TiDB Serverless cluster](/tidb-cloud/create-tidb-cluster-serverless.md).
 
-## Update spend limit
+## Update spending limit
 
-For an existing TiDB Serverless cluster, you can increase the usage quota by updating the spend limit as follows:
+For an existing TiDB Serverless cluster, you can increase the usage quota by updating the spending limit as follows:
 
 1. On the [**Clusters**](https://tidbcloud.com/console/clusters) page of your project, click the name of your target cluster to go to its overview page.
 
@@ -38,7 +38,7 @@ For an existing TiDB Serverless cluster, you can increase the usage quota by upd
 
 2. In the **Usage This Month** area, click **Get more usage quota**.
 
-    If you have previously updated the spend limit for a cluster and want to increase it further, click <svg width="14" height="14" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M11 3.99998H6.8C5.11984 3.99998 4.27976 3.99998 3.63803 4.32696C3.07354 4.61458 2.6146 5.07353 2.32698 5.63801C2 6.27975 2 7.11983 2 8.79998V17.2C2 18.8801 2 19.7202 2.32698 20.362C2.6146 20.9264 3.07354 21.3854 3.63803 21.673C4.27976 22 5.11984 22 6.8 22H15.2C16.8802 22 17.7202 22 18.362 21.673C18.9265 21.3854 19.3854 20.9264 19.673 20.362C20 19.7202 20 18.8801 20 17.2V13M7.99997 16H9.67452C10.1637 16 10.4083 16 10.6385 15.9447C10.8425 15.8957 11.0376 15.8149 11.2166 15.7053C11.4184 15.5816 11.5914 15.4086 11.9373 15.0627L21.5 5.49998C22.3284 4.67156 22.3284 3.32841 21.5 2.49998C20.6716 1.67156 19.3284 1.67155 18.5 2.49998L8.93723 12.0627C8.59133 12.4086 8.41838 12.5816 8.29469 12.7834C8.18504 12.9624 8.10423 13.1574 8.05523 13.3615C7.99997 13.5917 7.99997 13.8363 7.99997 14.3255V16Z" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"></path></svg> **Edit**.
+    If you have previously updated the spending limit for a cluster and want to increase it further, click <svg width="14" height="14" viewBox="0 0 24 24" fill="none" xmlns="http://www.w3.org/2000/svg"><path d="M11 3.99998H6.8C5.11984 3.99998 4.27976 3.99998 3.63803 4.32696C3.07354 4.61458 2.6146 5.07353 2.32698 5.63801C2 6.27975 2 7.11983 2 8.79998V17.2C2 18.8801 2 19.7202 2.32698 20.362C2.6146 20.9264 3.07354 21.3854 3.63803 21.673C4.27976 22 5.11984 22 6.8 22H15.2C16.8802 22 17.7202 22 18.362 21.673C18.9265 21.3854 19.3854 20.9264 19.673 20.362C20 19.7202 20 18.8801 20 17.2V13M7.99997 16H9.67452C10.1637 16 10.4083 16 10.6385 15.9447C10.8425 15.8957 11.0376 15.8149 11.2166 15.7053C11.4184 15.5816 11.5914 15.4086 11.9373 15.0627L21.5 5.49998C22.3284 4.67156 22.3284 3.32841 21.5 2.49998C20.6716 1.67156 19.3284 1.67155 18.5 2.49998L8.93723 12.0627C8.59133 12.4086 8.41838 12.5816 8.29469 12.7834C8.18504 12.9624 8.10423 13.1574 8.05523 13.3615C7.99997 13.5917 7.99997 13.8363 7.99997 14.3255V16Z" stroke="currentColor" stroke-width="2" stroke-linecap="round" stroke-linejoin="round"></path></svg> **Edit**.
 
-3. Edit the monthly spend limit as needed. If you have not added a payment method, you will need to add a credit card after editing the limit.
-4. Click **Update Spend Limit**.
+3. Edit the monthly spending limit as needed. If you have not added a payment method, you will need to add a credit card after editing the limit.
+4. Click **Update Spending Limit**.

tidb-cloud/select-cluster-tier.md

@@ -20,7 +20,7 @@ TiDB Serverless is a fully managed, multi-tenant TiDB offering. It delivers an i
 
 ### Usage quota
 
-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 [spend limit](/tidb-cloud/tidb-cloud-glossary.md#spend-limit) for the usage.
+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](/tidb-cloud/tidb-cloud-glossary.md#spending-limit) for the usage.
 
 For the first five TiDB Serverless clusters in your organization, TiDB Cloud provides a free usage quota for each of them as follows:
 
@@ -29,7 +29,7 @@ For the first five TiDB Serverless clusters in your organization, TiDB Cloud pro
 
 A Request Unit (RU) is a unit of measure used to represent the amount of resources consumed by a single request to the database. The amount of RUs consumed by a request depends on various factors, such as the operation type or the amount of data being retrieved or modified.
 
-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](/tidb-cloud/manage-serverless-spend-limit.md#update-spend-limit) or the usage is reset upon the start of a new month. For example, when the storage of a cluster exceeds 5 GiB, the maximum size limit of a single transaction is reduced from 10 MiB to 1 MiB.
+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](/tidb-cloud/manage-serverless-spend-limit.md#update-spending-limit) or the usage is reset upon the start of a new month. For example, when the storage of a cluster exceeds 5 GiB, the maximum size limit of a single transaction is reduced from 10 MiB to 1 MiB.
 
 To learn more about the RU consumption of different resources (including read, write, SQL CPU, and network egress), the pricing details, and the throttled information, see [TiDB Serverless Pricing Details](https://www.pingcap.com/tidb-cloud-serverless-pricing-details).
 

tidb-cloud/serverless-faqs.md

@@ -20,25 +20,64 @@ TiDB Serverless offers the TiDB database with full HTAP capabilities for you and
 
 Get started with the 5-minute [TiDB Cloud Quick Start](/tidb-cloud/tidb-cloud-quickstart.md).
 
-### Is TiDB Serverless free?
+### How many TiDB Serverless clusters can I create in TiDB Cloud?
 
-Each TiDB Serverless cluster has a free [usage quota](/tidb-cloud/serverless-limitations.md#usage-quota). 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](/tidb-cloud/manage-serverless-spend-limit.md#update-spend-limit) or the usage is reset upon the start of a new month.
+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](/tidb-cloud/tidb-cloud-glossary.md#spending-limit) for usage.
+
+### Are all TiDB Cloud features fully supported on TiDB Serverless?
+
+Some of TiDB Cloud features are partially supported or not supported on TiDB Serverless. For more information, see [TiDB Serverless Limitations and Quotas](/tidb-cloud/serverless-limitations.md).
+
+### When will TiDB serverless be available on cloud platforms other than AWS, such as GCP or Azure?
+
+We are actively working on expanding TiDB Serverless to other cloud platforms, including GCP 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.
+
+## Billing and metering FAQs
+
+### What are Request Units?
+
+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)](/tidb-cloud/tidb-cloud-glossary.md#request-unit). RU is an abstract measurement for the size and intricacy of requests initiated on your cluster. For more information, see [TiDB Serverless Pricing Details](https://www.pingcap.com/tidb-cloud-serverless-pricing-details/).
+
+### Is there any free plan available for TiDB Serverless?
+
+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)](/tidb-cloud/tidb-cloud-glossary.md#request-unit): 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](/tidb-cloud/manage-serverless-spend-limit.md#update-spending-limit) or the usage is reset upon the start of a new month.
 
 For more information, see [TiDB Serverless usage quota](/tidb-cloud/select-cluster-tier.md#usage-quota).
 
-### What are the limitations of a TiDB Serverless cluster?
+### How can I estimate the number of RUs required by my workloads and plan my monthly budget?
 
-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 [spend limit](/tidb-cloud/tidb-cloud-glossary.md#spend-limit) for the usage.
+To get the RU consumption of individual SQL statements, you can use the [`EXPLAIN ANALYZE`](/sql-statements/sql-statement-explain-analyze.md) SQL statement. 
 
-Some of TiDB Cloud features are partially supported or not supported on TiDB Serverless. See [TiDB Serverless Limitations and Quotas](/tidb-cloud/serverless-limitations.md) for details.
+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](/tidb-cloud/manage-serverless-spend-limit.md).
 
-### What can TiDB Serverless be used for?
+### How storage is metered for TiDB Serverless？
 
-You can use your TiDB Serverless cluster for non-production workloads such as prototype applications, development environments, hackathons, and academic courses, or to provide temporary data service for your datasets.
+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.
 
-### I created a Developer Tier cluster before TiDB Serverless was available. Can I still use my cluster?
+### Why does the storage usage size remain unchanged after dropping a table or database immediately?
 
-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.
+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`](/sql-statements/sql-statement-flashback-table.md)/[`FLASHBACK DATABASE`](/sql-statements/sql-statement-flashback-database.md) feature feasible, which allows you to recover dropped tables and databases if they were mistakenly deleted.
+
+### Why are there RU consumptions when I'm not actively running any queries?
+
+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.
+
+### Why is there a spike in RU usage when my workload is steady?
+
+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.
+
+### What happens when my cluster exhausts its free quota or exceeds its spending limit?
+
+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](/tidb-cloud/serverless-limitations.md#usage-quota).
 
 ## Security FAQs