The diagnostics feature of ApsaraDB PolarDB MySQL-compatible edition clusters can be used together with some features of Database Autonomy Service (DAS). You can enable the automatic specification change feature on the Autonomy Center tab. This topic describes how to enable the automatic specification change feature.

Prerequisites

  • Only ApsaraDB PolarDB MySQL-compatible edition Cluster Edition is supported. Single Node and Archive Database are not supported. For more information about the three editions of PolarDB for MySQL, see Product editions.
  • No tasks for specification changes for your PolarDB cluster are in the pending state.
  • Your ApsaraDB PolarDB MySQL-compatible edition clusters are pay-as-you-go clusters. Subscription clusters do not support the automatic specification change feature.

Pricing

For information about the pricing rules, see Configuration change fees.

Precautions

  • You can upgrade or downgrade the specifications of a cluster as a whole. You cannot upgrade or downgrade the specifications of individual nodes in the cluster.
  • Upgrading or downgrading the specifications of a cluster does not have any impact on the existing data in the cluster.
  • You may experience PolarDB service interruptions for a few seconds when you change specifications. During this time, you cannot perform some operations. We recommend that you change specifications during off-peak hours and make sure that your applications can automatically reconnect to the cluster.
  • In most scenarios, it takes more time to execute read-only requests than read and write requests. The time required to execute read-only requests may further increase when you change the specifications of a PolarDB cluster.

Procedure

  1. Log on to the PolarDB console.
  2. In the upper-left corner of the console, select the region where the cluster is deployed.
  3. On the Clusters page, find the cluster for which you want to enable the automatic specification change feature and click the cluster ID.
  4. In the left-side navigation pane, choose Diagnostics and Optimization > Diagnosis.
  5. On the page that appears, click the Autonomy Center tab.
  6. In the upper-right corner of the tab, click Autonomy Service Settings.
    Autonomy Service Settings
  7. On the Autonomy Service Settings tab of the Settings dialog box, turn on Enable Autonomy and then turn on Automatic Scale-up/out and Automatic Scale-down/in.
    Note
    • After you turn on Automatic Scale-up/out, if the CPU utilization is greater than or equal to the specified value during the observation period, PolarDB automatically adds nodes or upgrades the specifications of your cluster after the observation period expires. This ensures that the cluster can handle the read and write requests that the cluster received. For example, if the observation period is 5 minutes and the time required for automatic scale-out in 10 minutes, you must wait 15 minutes to check the scale-out effect.
    • After you turn on Automatic Scale-down/in, if the CPU utilization remains at less than 30% for more than 99% of the quiescent period, automatic scale-in is triggered after the quiescent period expires. The specifications of the PolarDB cluster are gradually scaled in to the original specifications.
    Enable Autonomy
  8. Specify the Automatic Scale-up/out and Automatic Scale-down/in parameters and click OK.
    Parameter Description
    Average CPU Utilization The threshold based on which automatic scale-out is triggered. If the average CPU utilization is greater than or equal to the specified value, automatic scale-out is triggered.
    Maximum Specifications The upper limit of the specifications based on which you can upgrade your clusters. After automatic scale-out is triggered, the system gradually upgrades the specifications of your PolarDB cluster to the upper limit. For example, the specifications can be upgraded from 4 cores to 8 cores and then to 16 cores.
    Max number of Read-Only nodes The maximum number of read-only nodes that can be automatically added to the cluster. After automatic scale-out is triggered, the read-only nodes of the PolarDB cluster are added one by one until the upper limit is reached.
    Note The nodes that are automatically added are associated with the default endpoint of your cluster. If you use a custom endpoint, you must specify whether these nodes are automatically associated with the endpoint by using the Automatically Associate New Nodes parameter. For more information about Automatically Associate New Nodes, see Manage a cluster endpoint.
    Observation Window If the CPU utilization is greater than or equal to the specified value during the observation period, PolarDB automatically adds nodes or upgrades the specifications of your cluster after the observation period expires. This ensures that the cluster can handle the read and write requests that the cluster received. For example, if the observation period is 5 minutes and the time required for automatic scale-out in 10 minutes, you must wait 15 minutes to check the scale-out effect.
    Quiescent Period The minimum interval between two automatic scale-in operations or two automatic scale-out operations. During a quiescent period, PolarDB continuously tracks whether the conditions based on which automatic scale-out or scale-in are triggered are met. However, automatic scale-out or scale-in is not triggered. If a quiescent period and an observation period expire at the same time and the CPU utilization reaches the threshold within the observation period, PolarDB automatically triggers automatic scale-out when the two periods expire.