To provide a reliable, high-quality cloud database service, Alibaba Cloud may initiate scheduled O&M events on some of your instances to upgrade software, hardware, configurations, and the network. These events include instance migration, primary/secondary switchover, version upgrades, and parameter modifications. These events typically cause transient connection interruptions, so ensure your application has a reconnection mechanism. Refer to the description of each event for its actual impact.
Event notifications
Notifications for scheduled events are typically sent 1 to 3 days in advance by email based on your settings in Message Center. To receive these notifications, ensure that the correct recipients are configured in your Alibaba Cloud account and that subscriptions are enabled for . After receiving a notification titled "Notification of ApsaraDB for Planned operation and maintenance", you can view details on the Scheduled Events page in Event Center (or Event Management). These details include the event type, region, reason, cancellation risk, and affected instances. You can also adjust the scheduled switchover time of an instance to its off-peak hours as needed.
Notes
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Events are classified into two levels of urgency:
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[S0 Urgent] Risk Remediation: Typically involves unexpected issues requiring immediate action to prevent service failures. Notifications for these events are sent three days or less in advance, and the window for rescheduling the switchover time is shorter. Examples include urgent version replacement and upgrades, host failure recovery, and upgrades for expiring SSL certificates.
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[S1 Scheduled] System Maintenance: Involves low-risk issue fixes or planned software and hardware upgrades. Notifications for these events are usually sent more than three days in advance, and you can cancel the event.
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To receive notifications for scheduled O&M events, log on to the Message Center, and select the notification methods and configure contacts for ApsaraDB Fault or Maintenance Notifications. We recommend adding your database O&M personnel as contacts. Otherwise, you will not receive event notifications.Notification methods include Email and Internal Messages. We recommend you select Email to ensure delivery.
In the upper-right corner of the console, click the bell icon. Then, in the Internal Message Notifications panel, click Message Settings.
Figure 1. Accessing Message Settings

Figure 2. Notification settings for ApsaraDB
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To receive real-time updates on O&M events or implement custom, event-driven automation, configure system event subscriptions in CloudMonitor. ApsaraDB pushes system events to CloudMonitor for each stage of the O&M event lifecycle, such as Scheduled, In Progress, Succeeded, and Canceled. For more information, see Manage event subscriptions (Recommended). For a list of subscribable CloudMonitor events, see Appendix 1: CloudMonitor-related system events.
Procedure
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Log on to the console for your database product.
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In the navigation pane on the left, click . In the top navigation bar, select the region where your instance is located.
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The Scheduled Events page shows the details of scheduled events. By default, events with the Planned status are displayed. To view historical events, click the Completed or Canceled tab. The following table describes the event attributes.
Attribute
Example
Description
Event type
Risk remediation
Events are classified by urgency into two types: Risk remediation and system maintenance.
Status
Pending
The scheduling status of the event. Note the following key statuses:
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Waiting Setting Time: The execution time is not set. You must set a time based on your business requirements. If you do not set a time by the Deadline, the event is automatically canceled.
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Pending: The event is waiting to enter the scheduling phase at the scheduled Start time.
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Executing: The event is in progress. You cannot manually intervene at this stage. To request an emergency stop, submit a ticket. Note that such non-standard operations can pose unknown risks.
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Successful: The event has completed.
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Canceled: The event execution failed or was canceled. Common reasons for cancellation include:
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Canceled by user (UserCancel): The user canceled the event in the console or by calling an API operation.
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User response timeout (UserResponseTimeout): The event was automatically canceled because the execution time was not set before the Deadline.
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Canceled by control system (SupervisorCancel): The event initiator canceled the event.
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Canceled as unnecessary (AvoidCancel): The event is no longer required because the risk has been resolved or the instance's current state makes the event obsolete. For example, the instance is already on the latest version and requires no update.
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Canceled by system (AutoCancel): The system periodically inspects scheduled events. The event is canceled if the instance does not meet the execution prerequisites, for example, if the instance is in an abnormal state and cannot receive commands.
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Execution timeout (ExecuteTimeout): The event entered the execution queue but did not finish within the expected time.
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Execution failure (ExecuteFail): The event failed during execution due to an unknown error.
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Event type
minor version update
The specific name of the event type. For more information, see Event types and impacts.
Cause
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For more information, see Appendix 2: Detailed cause codes and cancellation risks.
Business impact
Transient connection interruption
The business impact varies depending on the event. For more information, see Event types and impacts.
O&M suggestions
Ensure your application has an automatic reconnection mechanism and is designed to handle the potential business impact.
O&M suggestions vary depending on the event. For more information, see Appendix 1: CloudMonitor-related system events.
Start time
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The time when the event enters the scheduling queue. Before the start time, the event does not affect the instance. After the start time, your database remains accessible, but you cannot perform instance-level operations such as changing the configuration or migrating across availability zones. This field is empty if the event status is Waiting Setting Time.
Scheduled switchover time
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The time when a primary/secondary switchover or link switchover occurs, if applicable. This is typically when a transient connection interruption happens. The switchover is expected to occur around this estimated time. In rare cases, such as a failback to the original availability zone, a second switchover may occur.
NoteA preparation period is required before the switchover for tasks such as event scheduling and data preparation. Therefore, a time gap exists between the start time and the switchover time. This gap varies by database product and event type.
Deadline
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The latest time by which you can set the switchover time. The adjusted switchover time cannot be later than this Deadline.
Cancelable
Yes
You can cancel the event to prevent it from running. This option is typically available for "system maintenance" events.
ImportantScheduled events are typically issued by the cloud database management system during regular inspections. If you cancel an event, a new one may be issued in the next inspection cycle. Frequent cancellations can increase risks. To avoid these risks, schedule the event for a suitable time based on your business needs instead of canceling it. For more information about cancellation risks, see Appendix 2: Detailed cause codes and cancellation risks.
Reschedulable
Yes
You can change the execution time for most events. In rare cases involving urgent, high-risk fixes, the time window may not be long enough to allow for rescheduling.
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(Optional) Modify a scheduled event.
Select the event that you want to reschedule and click Modify Scheduled Event. You can modify the event in one of two ways:
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Immediate execution: The event's start time is set to the current time, and it enters the execution queue immediately.
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Switchover at a specified time: Select a suitable time for the switchover from the available range. The start time is automatically calculated based on the switchover time. The new start time cannot be earlier than the current time. Otherwise, the modification fails.
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(Optional) Modify the recurring time window.
In the upper-right corner of the event list, click Recurring Time Window Settings to open the configuration page.
The execution time of a scheduled event is typically calculated based on the instance's maintenance window. For more information, see the documentation about setting the maintenance window for RDS, Tair, MongoDB, and PolarDB. You can also define a custom recurring time window to meet your O&M requirements. The cloud database service then prioritizes this custom window when scheduling new events.
You can set the window on a weekly or monthly basis. For example, if you set the recurring switchover time to 02:00–03:00 on every Monday and Tuesday, and the platform's overall event window is from this Tuesday to the following Sunday, the system will identify both 02:00–03:00 on this Tuesday and 02:00–03:00 on next Monday as valid switchover times. Typically, the earlier time (this Tuesday) is prioritized.
Important-
This setting applies only to new events. To change the time of an existing event in the list, click Configure Execution Time.
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This setting is only an aid for calculating the execution time and applies only to "system maintenance" events. The actual execution time is subject to the time displayed in the event list.
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This is an account-level setting. Once configured, it applies to all database products that support recurring time windows.
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(Optional) Cancel a scheduled event.
Select the event you want to cancel and click Cancel Scheduled Event. After reviewing the risks, click Confirm to cancel the event.
Event types and impact
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Event type |
Description |
Impact type |
Impact |
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Instance migration |
During this planned maintenance, the system migrates the instance to a new host to address host risks, expiring hardware, or operating system upgrades. This applies to non-high-availability instances and read-only instances. |
Transient connection |
After the scheduled switchover time, the following impacts occur: Note
A pending event typically involves an instance switchover, which is performed during the maintenance window after the scheduled switchover time.
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Primary/secondary switchover |
During this planned maintenance, the system performs a primary/secondary switchover to address host risks, expiring hardware, or operating system upgrades. This operation applies only to high-availability instances. |
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Instance parameter modification |
During this planned maintenance, the system modifies instance parameters to address known risks. If the specified parameters require a restart, the instance is restarted. |
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Host risk remediation |
The system fixes fault risks on the host where the instance runs. |
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SSL certificate update |
The system updates the SSL certificate before it expires to ensure continued security and stability. |
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Backup mode upgrade |
This operation switches the instance's backup mode from logical to physical table-level backup to enable faster backup and recovery. |
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Cross-zone migration |
The system upgrades and retrofits the physical infrastructure in some legacy regions and zones. |
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Minor version update |
To improve user experience, the cloud database service periodically releases minor versions for instances to add features or fix known defects. |
Transient connection |
After the scheduled switchover time, the following impacts occur: Note
A pending event typically involves an instance switchover, which is performed during the maintenance window after the scheduled switchover time.
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Differences between minor versions |
Different minor versions (kernel versions) contain different updates. You should be aware of the differences between your current version and the target version. For details, see the release notes for the relevant product (minor version release notes are not yet available for some products):
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Proxy minor version update |
Proxy minor version updates add features or fix known defects to improve the user experience. |
Transient connection |
After the scheduled switchover time, the following impacts occur: Note
A pending event typically involves an instance switchover, which is performed during the maintenance window after the scheduled switchover time.
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Differences between minor versions |
Different minor versions contain different updates. You should be aware of the differences between your current version and the target version. For details, see the release notes for the relevant product (some products lack proxy nodes or do not provide release notes for their minor versions):
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Network upgrade |
The system upgrades network hardware to improve instance network performance and stability. |
Transient connection |
After the scheduled switchover time, the following impacts occur: Note
A pending event typically involves an instance switchover, which is performed during the maintenance window after the scheduled switchover time.
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Impact on VIP direct connections |
Some network upgrades may involve a cross-zone migration, which changes the virtual IP address (VIP) of the instance. If your client connects to the database using the VIP, the connection will be interrupted. Note
To avoid this impact, use the domain name endpoint provided for your instance and disable the DNS cache on your application and its server. |
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Storage gateway upgrade |
The system upgrades the storage gateway to improve storage performance and stability. |
I/O jitter |
This operation can cause brief I/O jitter or increased SQL latency for up to 3 seconds. |
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Enable seamless migration |
A parameter is modified to enable future seamless migration capabilities. |
Parameter modification |
No impact. Note
No restart or migration is involved, so your workloads are not affected. |
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Proxy node migration |
The system upgrades or maintains the host for the proxy node to improve its stability. |
Proxy node migration |
During the proxy node migration, the instance endpoint and custom endpoints will experience a transient connection for up to 10 seconds. |
Affected instances
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If a proposed switchover time is unsuitable, you can reschedule the event within 30 days of its creation.
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To receive immediate updates on scheduled events, such as their creation and execution status, configure event alerts in CloudMonitor. For more information, see Subscribe to event notifications.
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Instance type |
Engine |
References |
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N/A |
FAQ
Notifications
Start time and switchover time
Event operations
Other questions
Appendix
Appendix 1: CloudMonitor system events
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Event code |
Event name |
Trigger condition |
Recommendations |
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Instance:SystemMaintenance.MinorVersionUpgrade:Scheduled |
Minor version update (scheduled) |
A minor version update is scheduled. |
The event has not started. Instance availability is not affected. |
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Instance:SystemMaintenance.MinorVersionUpgrade:ReminderNotice |
Minor version update (reminder) |
Reminders are sent 7, 3, and 1 days before execution starts. |
This is an informational notification. The event has not yet started. |
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Instance:SystemMaintenance.MinorVersionUpgrade:Executing |
Minor version update (executing) |
The minor version update begins. |
To prevent unexpected issues, avoid manual intervention at this stage. |
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Instance:SystemMaintenance.MinorVersionUpgrade:Executed |
Minor version update (completed) |
The minor version update is complete. |
The event completed successfully. A primary/secondary switchover may occur. Monitor for any business impact. |
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Instance:SystemMaintenance.MinorVersionUpgrade:Canceled |
Minor version update (canceled) |
The minor version update fails or is canceled. |
The event failed or was automatically canceled, for example, because the instance is already on the latest version. Instance availability is unaffected. |
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Instance:SystemMaintenance.Transfer:ReminderNotice |
Instance migration (reminder) |
Reminders are sent 7, 3, and 1 days before execution starts. |
This is an informational notification. The event has not yet started. |
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Instance:SystemMaintenance.Transfer:Scheduled |
Instance migration (scheduled) |
An instance migration is scheduled. |
The event has not started. Instance availability is not affected. |
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Instance:SystemMaintenance.Transfer:Executing |
Instance migration (executing) |
The instance migration begins. |
To prevent unexpected issues, avoid manual intervention at this stage. |
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Instance:SystemMaintenance.Transfer:Executed |
Instance migration (completed) |
The instance migration is complete. |
The event completed successfully. A primary/secondary switchover may occur. Monitor for any business impact. |
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Instance:SystemMaintenance.Transfer:Canceled |
Instance migration (canceled) |
The instance migration fails or is canceled. |
The event failed or was automatically canceled, for example, because the instance had already been manually migrated. Instance availability is unaffected. |
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Instance:SystemMaintenance.ScheduledOperation:ReminderNotice |
Scheduled event (reminder) |
Reminders are sent 7, 3, and 1 days before execution starts. |
This is an informational notification. The event has not yet started. |
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Instance:SystemMaintenance.ScheduledOperation:Scheduled |
Scheduled event (scheduled) |
A scheduled event is scheduled. |
The event has not started. Instance availability is not affected. |
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Instance:SystemMaintenance.ScheduledOperation:Executing |
Scheduled event (executing) |
The scheduled event begins. |
To prevent unexpected issues, avoid manual intervention at this stage. |
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Instance:SystemMaintenance.ScheduledOperation:Executed |
Scheduled event (completed) |
The scheduled event is complete. |
The event completed successfully. A primary/secondary switchover may occur. Monitor for any business impact. |
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Instance:SystemMaintenance.ScheduledOperation:Canceled |
Scheduled event (canceled) |
The scheduled event fails or is canceled. |
Instance availability is unaffected. |
For more information, see Supported cloud services and their system events.
Appendix 2: Reason codes and cancellation risks
|
Cause code |
Cause description |
Risk code |
Risk description |
Notes |
Frequency |
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InfraArchUpgrade |
Replacement or upgrade of the underlying infrastructure architecture. |
OutOfGoodPerfByHardwareUpgrade |
You cannot benefit from the improved performance and stability of the upgraded software. |
We upgrade or migrate instances to improve service quality and stability as our underlying compute, storage, and network architecture evolves. |
Monthly/Quarterly |
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EnhanceStabilityAndResUtil |
Improves instance stability and resource utilization. |
ImpactStabAndResContention |
Affects instance stability. Potential impacts include resource contention, engine vulnerabilities, and lower-than-expected performance. |
- |
Irregularly |
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EnableHotReplica |
Enabling seamless migration significantly improves the high availability of your database instance. This feature also speeds up maintenance tasks like instance scaling, minor version upgrades, and migrations, without affecting your services. |
- |
- |
- |
- |
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KernelExceptionRepair |
Fixes instance exceptions caused by the engine. |
RiskEscatateToFailure |
This risk can escalate to a failure, impacting instance availability. |
This is common for urgent risk remediation in an engine version. |
Irregularly |
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OldKernelVersionWithHardwareUpgrade |
The outdated engine version is upgraded along with hardware resources. |
KernelVersionEndOfLife |
The engine version's lifecycle has ended. The instance cannot use new features or benefit from performance optimizations. |
This is common for routine version updates and upgrades. |
Monthly/Quarterly |
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KernelBugFix |
Fixes engine vulnerabilities. |
RiskEscatateToFailure |
This risk can escalate to a failure, impacting instance availability. |
This is common for urgent bug fixes in an engine version. |
Irregularly |
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HostLoadHigh |
Excessive host load. |
HostLoadHighAffectStability |
Excessive host load affects the performance and stability of the instance. |
This is common for mitigating host hardware risks. |
Irregularly |
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SoftwareUpgrade |
Host software upgrade. |
OutOfGoodPerfByHardwareUpgrade |
You cannot benefit from the improved performance and stability of the upgraded software. |
A cold upgrade of the host's operating system or dependent plugins. |
Monthly/Quarterly |
|
HardwareUpgrade |
Replacement or upgrade of the underlying hardware. |
OutOfGoodPerfBySoftwareUpgrade |
You cannot benefit from the improved performance and stability of the upgraded software. |
Host hardware upgrade. |
Monthly/Quarterly |
|
HostSoftHardwareUpgrade |
Host software or hardware upgrade. |
OutOfGoodPerfBySoftHardwareUpgrade |
You cannot benefit from the improved performance and stability of the upgraded software. |
Host software and hardware upgrade. |
Monthly/Quarterly |
|
ProxyNodeHostMaintain |
Maintenance or upgrade of the proxy node's host. |
Proxy node host maintenance/upgrade |
Host risks affect the stability of the proxy node. |
- |
- |
|
HostCPUException |
Host CPU exception. |
RiskEscatateToFailure |
This risk can escalate to a failure, impacting instance availability. |
- |
Irregularly |
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HostMemException |
Host memory exception. |
RiskEscatateToFailure |
This risk can escalate to a failure, impacting instance availability. |
- |
Irregularly |
|
HostDiskException |
Host disk exception. |
RiskEscatateToFailure |
This risk can escalate to a failure, impacting instance availability. |
- |
Irregularly |
|
KernelVersionWithServerlessUpgrade |
The engine is upgraded, and the instance moves from public preview to general availability (GA). |
BetaVersionEndOfLife |
The lifecycle of the public preview version has ended. The instance cannot use new features or benefit from performance optimizations. |
- |
Monthly/Quarterly |
|
ParamRiskRepairOrOptimize |
Fixes or optimizes parameters to address associated risks. |
UnknownRisks |
May lead to unknown risks. |
This is common for automatic tuning events triggered by suboptimal parameter settings in a cloud database. |
Monthly/Quarterly |
|
PGOldKernelVersionWithHardwareUpgrade |
The outdated engine version is upgraded along with the hardware resources. This may change the database port and cross-database connection string. The TimescaleDB, PostGIS, and Ganos plugins will also be upgraded to their latest versions, as older versions are incompatible. |
KernelVersionEndOfLife |
The engine version's lifecycle has ended. The instance cannot use new features or benefit from performance optimizations. |
- |
Monthly/Quarterly |
|
MaxScaleExceptionRepair |
Remediates risks in the proxy component. |
RiskEscatateToFailure |
This risk can escalate to a failure, impacting instance availability. |
This is common for urgent risk remediation in a proxy service version. |
Irregularly |
|
OriginalNetWorkHasFlawWithSqlTimeoutAndDIsconnection |
The current network type has flaws that cause slow SQL query timeouts and intermittent disconnections. This upgrade improves stability by resolving these issues. |
FlawNotResolvedAndAbnormalConnectionMayOccur |
If not resolved, these network flaws may cause connection issues. |
- |
Irregularly |
Appendix 3: Event types
|
Event type |
Description |
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instance migration |
instance migration |
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minor version update |
minor version update |
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network upgrade |
network upgrade |
|
primary/secondary switchover |
primary/secondary switchover |
|
SSL certificate update |
SSL certificate update |
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proxy minor version update |
proxy minor version update |
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instance parameter modification |
instance parameter modification |
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major version update |
major version update |
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live migration |
live migration |
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proxy migration |
proxy migration |