Setting Elastic Rules
Last updated:2026-03-03 14:30:31
Serverless clusters support configuring rule-based elastic policies for instances based on business traffic. Once set, instances can trigger elastic adjustments to the computing power range according to predefined rule-based elastic policies and elastic plans, avoiding potential jitter during peak business hours. You can configure rule-based elastic policies for different cycles to meet performance requirements across time periods. Additionally, you can query and manage rule-based elastic policies and execution plans via the console. This document introduces the feature description and related operations for rule-based elasticity.
Billing Instructions
The rule-based elastic feature is currently in open beta, and no charges are incurred for now.
Introduction of Supported Modes and Versions
Clusters in Serverless instance mode support setting this feature for Serverless instances under the cluster.
TDSQL-C for MySQL database versions MySQL 5.7 and MySQL 8.0 all support this feature.
Feature Overview
The computing power range of your Serverless cluster defaults to the settings at the time of cluster creation. To enable the rule-based elastic feature, you can add a rule-based elastic policy via the console. Adding it enables the rule-based elastic feature.
You can add rule-based elastic policies to read-write instances or read-only instances under a Serverless cluster.
After adding a rule-based elastic policy to an instance under a Serverless cluster, you can copy, modify, or delete that policy.
After adding a rule-based elastic policy to an instance under a Serverless cluster, you can query the corresponding elastic plan. The console will display the most recent elastic plan in that policy, which can be manually canceled before execution.
For the same type of instances (read-write instances or read-only instances) under the same Serverless cluster, you cannot set rule-based elastic policies for time periods that overlap with existing policies on those instances.
When a rule-based elastic policy is set, the minimum and maximum computing power cannot be set beyond the current computing power range of the corresponding instance. To set a higher computing power, you can first adjust the configuration.
Clusters in the "Paused" state cannot perform the following operations. Please start the cluster before performing the corresponding operations.
Enable Rule-Based Elastic Scaling
1. Log in to the TDSQL-C for MySQL console.
2. Click the target cluster in the cluster list on the left to go to the Cluster Management page.
3. Choose Elastic Scaling Management Tool > Rule-Based Elastic Scaling, and click Add Policy.
4. In the policy list, after setting the policy, click OK in the Operations column.
Parameter | Description |
Policy ID | After the policy is set, the system will generate a policy ID for querying the policy and referencing elastic scaling plan. |
Instance Type | If the cluster architecture is single-node, this item defaults to read-write instance; if the cluster architecture is cluster edition, this item supports custom selection: read-write instance or read-only instance. |
Recurrence Rule | Please set duplicate policies. Daily: When the cycle is set to Daily, please set the start and end time, such as: 01:00 - 02:00. Every week: When the cycle is set to Every week, first select the day of the week, default select 1 (indicating Monday), range: 1 - 7, supports multiple selection, then set the start and end time. Every month: When the cycle is set to Every month, first select the day(s), default select 1 (indicating the 1st day of the month), range: 1 - 31, supports multiple selection, then set the start and end time. |
Elastic Scaling Range (ccu) | Please set the elastic scaling range. For the limitation description of the setting, see Feature Overview. |
Effective Period | Please set the effective time range for this elastic policy, for example: 2026-03-01 00:00:00 ~ 2026-03-15 23:59:59. Note: Support down to the second. If you set dates only without specifying specific times, the time range will default to 00:00:00 on the start date to 23:59:59 on the end date. |
Enabling Status | Indicates whether the elastic policy of the current rule is effective. |
Operation | OK: Click to complete the setup. Cancel: Click to cancel the setup. |
Copy Rule Elastic Policy
You can quickly copy an existing rule elastic policy and edit it based on it. The operation location is as shown below.
Modify Existing Rule Elastic Policy
By editing the rule elastic policy, you can modify existing rules including: changing the cycle, adjusting the time range, updating the elastic scope, and modifying the effective period. The operation location is as shown below.
Delete Rule Elastic Policy
If a rule elastic policy is no longer applicable, you can delete it. The operation location is as shown below.
Query and Cancel Elastic Scaling Plan
1. Log in to the TDSQL-C for MySQL console.
2. Click the target cluster in the cluster list on the left to go to the Cluster Management page.
3. Choose Elastic Scaling Management Tool > Elastic Scaling Plan, you can query detailed elastic plans in the list, including system-terminated historical elastic plans, elastic plans that are canceling or have been canceled, and elastic plans pending task generation.
4. To cancel an elastic plan pending task generation, click Plan Cancellation, then click OK in the pop-up window.
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