PolarDB for MySQL provides the Quick Diagnostics feature, which integrates some features of Database Autonomy Service (DAS) and includes the Autonomy Center, where you can enable the autonomy service. After the autonomy service is enabled, DAS automatically performs root cause analysis when it detects database anomalies and provides optimization or loss mitigation suggestions. DAS also automatically performs optimization or loss mitigation operations, and optimization operations start only after you grant authorization.
Considerations
Automatic Scale-up/out and Automatic Scale-down/in are supported only when the Commodity Type is set to Pay-As-You-Go for PolarDB for MySQL clusters. Subscription clusters do not support Automatic Scale-up/out or Automatic Scale-down/in. For more information about commodity types, see Custom purchase.
Procedure
Log on to the PolarDB console.
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In the navigation pane on the left, click Clusters。
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In the upper-left corner, select the region where the cluster is deployed.
On the Clusters page, click the ID of the target cluster.
In the left-side navigation pane, choose .
Click the Autonomy Center tab.
In the upper-right corner, click Autonomy Service Settings.
In the Autonomous Function Management dialog box, click the Autonomous Function Settings tab, and then turn on the Autonomous Function Management switch.
NoteAfter you enable the autonomy features, the system automatically performs capacity assessment, session analysis, SQL throttling analysis, and exception snapshot saving. These operations do not add extra load to the database.
The autonomy service includes Auto Index Creation and Deletion, Auto Throttling, Auto Scaling, and Auto Scaling-in.
Auto Index Creation and Deletion: After you turn on the Enable Autonomy Service switch, SQL Diagnostics Only is enabled by default.
If you select SQL Diagnostics Only, the system runs scheduled daily diagnostics on SQL statements and generates index optimization suggestions, but does not create the indexes on your cluster.
If you select SQL Diagnostics and Automatic Index Creation, the system runs scheduled daily diagnostics on SQL statements, generates index optimization suggestions, and creates the indexes on your cluster.
NoteAutomatic SQL optimization creates indexes only during the maintenance window of the cluster.
Auto Throttling: You can customize the throttling trigger conditions. When the conditions are met, SQL throttling is automatically triggered.
NoteFor example, within the throttling time range (00:00 to 23:59 by default), you can set a custom trigger condition. The condition can specify that automatic throttling starts when CPU utilization exceeds 70%, the number of active sessions exceeds 16, and this state persists for more than 2 minutes. Tracking also starts automatically. If the fault is not resolved, the throttling operation is automatically rolled back. After automatic throttling is triggered, the throttling operation does not last longer than the maximum throttling duration. For details, see Automatic SQL throttling.
Auto Scaling and Auto Scaling-in: You can turn on the automatic scaling switch and customize the scaling trigger conditions. When the conditions are met, the system automatically triggers scaling.
Parameter
Description
Auto Scaling-out
The switch that enables auto scaling.
Observation Period
If the average CPU utilization is greater than or equal to the specified value throughout the observation window, then after the observation window ends, PolarDB selects a scaling method of adding nodes or upgrading specifications based on the real-time read and write traffic of the cluster. The minimum observation window is 5 minutes, so the waiting time is at least 15 minutes. For example, if the observation window is 5 minutes and auto scaling takes 10 minutes, you need to wait about 15 minutes to see the effect of auto scaling.
NoteThe scale-in observation window is the observation window plus 10 minutes. For example, if Observation Window is set to 30 minutes, the scale-in observation window is 40 minutes.
CPU Usage
The threshold that triggers auto scaling. When CPU Usage is greater than or equal to the specified value, auto scaling is triggered.
Maximum Specification
The upper specification limit for auto scaling. After auto scaling is triggered, the cluster specifications of PolarDB are upgraded tier by tier, for example, from 4 cores to 8 cores and then to 16 cores, until the upper scaling limit is reached.
Maximum Number of Read-only Nodes
The maximum number of read-only nodes that auto scaling can add. After auto scaling is triggered, the system adds one to two read-only nodes based on actual conditions until the upper limit is reached.
NoteNodes added by auto scaling are associated with the default endpoint of the cluster. For a custom endpoint, you must configure Automatically Associate New Nodes. For more information about how to configure Automatically Associate New Nodes, see Configure the database proxy.
If you want to upgrade specifications only without adding nodes, set the upper limit of read-only nodes to the current number of read-only nodes.
Adding nodes does not cause a transient disconnection, but upgrading specifications does. In addition, a specification upgrade applies to all nodes in the cluster, not only the node that triggered the upgrade.
Auto Scaling-in
The switch that enables automatic scale-in.
NoteAfter automatic scale-in is enabled, if the cluster is not in the cool-down period and the average CPU utilization of the nodes added by auto scaling stays below 30% for more than 99% of the scale-in observation window (observation window + 10 minutes), the system automatically scales back the cluster specifications tier by tier until the original specifications are restored.
If the cluster has scaled out but has not yet scaled back, and you disable the auto scaling feature, the cluster is not automatically scaled back.
Quiescent Period
The minimum interval between two consecutive automatic scale-out or scale-in activities. During the cool-down period, PolarDB continues to monitor the cluster but does not trigger automatic scale-out or scale-in. If the cool-down period and the observation window end at the same time and the CPU utilization within that observation window reaches the adjustment threshold, PolarDB triggers an automatic specification adjustment when the cool-down period and the observation window end.
Click OK.