PolarDB notifies you at least three days before a scheduled O&M (operations and maintenance) event runs. From the console, you can view event details, reschedule the switching time, and configure a global scheduling preference.
Prerequisites
Before you begin, ensure that you have:
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Access to the PolarDB console
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Configured notification contacts in Message Center to receive alerts outside the console
Set up notifications
PolarDB sends event notifications through the following channels:
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Text message
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Phone call
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Email
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Internal message (console)
To receive notifications, log on to Message Center, enable ApsaraDB Fault or Maintenance Notifications, and add an O&M engineer as the contact. Without a configured contact, notifications are not delivered.
If you have questions about a scheduled event, join the DingTalk group (group number: 51685000218) for 24/7 support from PolarDB engineers and the chatbot assistant.
View scheduled events
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Log on to the PolarDB console.
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In the upper-left corner, select the region where the cluster is deployed.
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In the left-side navigation pane, choose Event Center > Scheduled Events.
If an event requires you to schedule a handling time, a prompt appears asking you to schedule it as soon as possible.
Reschedule a switching time
Limitations
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The scheduled switching time cannot be later than the Latest Start Time shown for the event.
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The Global Scheduler applies to all new scheduled O&M events except high-risk vulnerability fix events.
Configure the Global Scheduler (optional)
The Global Scheduler sets a recurring time window that new scheduled O&M events automatically adopt. If no Global Scheduler is configured, new events default to the cluster's maintenance window.
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On the Scheduled Events page, click Global Schedule.
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In the Global Scheduler panel, set the periodic switching time and click OK.
Change the switching time for a specific event
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On the Scheduled Events page, select the cluster and click Add Scheduled Time.
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In the Add Scheduled Time dialog box, set Scheduled Switching Time and click OK.
Event types and impacts
The following table describes each event type, its cause, and the impact during switching.
| Event type | Cause | Impact |
|---|---|---|
| Hot upgrade — instance migration | Host vulnerabilities, hardware warranty expiration, or OS upgrades. The system migrates non-high-availability clusters and read-only clusters to a new server. | Transient connections. Clusters or data shards stay in read-only state for up to 30 seconds while data synchronizes. During this window, Data Management (DMS) and Data Transmission Service (DTS) management operations are temporarily unavailable. Perform switching during off-peak hours and make sure your application reconnects automatically. |
| Hot upgrade — primary/read-only node switchover | Host vulnerabilities, hardware warranty expiration, or OS upgrades. The system switches workloads of high-availability clusters from primary nodes to read-only nodes. | Transient connections. Clusters or data shards stay in read-only state for up to 30 seconds while data synchronizes. DMS and DTS management operations are temporarily unavailable. Perform switching during off-peak hours and make sure your application reconnects automatically. |
| Hot upgrade — cluster parameter adjustment | Known parameter risks identified during scheduled O&M. The system modifies cluster parameters. | If the modified parameter requires a restart, the cluster restarts. |
| Hot upgrade — host vulnerability fix | Host vulnerabilities affecting the cluster's underlying host. | — |
| Hot upgrade — backup mode change | Switching the cluster's backup mode from logical backup to physical backup. | — |
| Hot upgrade — minor engine version update | A new minor version is available with additional features, bug fixes, or experience improvements. Check for differences between versions. | Transient connections. Clusters or data shards stay in read-only state for up to 30 seconds while data synchronizes. DMS and DTS management operations are temporarily unavailable. Perform switching during off-peak hours and make sure your application reconnects automatically. |
| Hot upgrade — minor version update for proxies | A new minor version is available for proxy nodes with additional features, bug fixes, or experience improvements. | Transient connections. Clusters or data shards stay in read-only state for up to 30 seconds while data synchronizes. DMS and DTS management operations are temporarily unavailable. Perform switching during off-peak hours and make sure your application reconnects automatically. |
| Hot upgrade — network upgrade | Scheduled to improve network performance and stability. Some upgrades involve cross-zone migrations, which change the cluster's virtual IP address. If your client connects using a virtual IP address instead of the cluster endpoint (domain name), the connection is interrupted. To avoid this, use the endpoint provided by the cluster and disable DNS caching in your application and server. | Transient connections for up to 30 seconds. DMS and DTS management operations are temporarily unavailable. |
| Hot upgrade — storage gateway upgrade | Scheduled to improve storage performance and stability. | Temporary I/O jitter and increased SQL latency for no longer than three seconds. |
| Cold upgrade — public preview version upgrade | Upgrading from a public preview version to an official release. | Transient connections and read-only state for up to two minutes. If the cluster has many table files, is running large transactions, or has high CPU utilization before the upgrade, the downtime usually exceeds two minutes. Perform the upgrade during off-peak hours and make sure your application reconnects automatically. Back up your data before upgrading major versions or public preview versions. |
For hot upgrades, the system typically switches workloads to a read-only node before the event starts. The actual switching happens within the maintenance window after the scheduled switching time.
API reference
| API | Description |
|---|---|
| DescribePendingMaintenanceActions | Queries the number of scheduled events by task type. |
| DescribePendingMaintenanceAction | Queries details about scheduled events. |
| ModifyPendingMaintenanceAction | Modifies the switching time of a scheduled event. |