:Performance snapshots

Scenarios

Assume that a MySQL database reports an alert. The alert indicates that the CPU utilization reaches 90% at 01:00:00 (UTC+8). As a result, the response time for service requests is prolonged. However, when the database administrator logs on to the database for troubleshooting, the system has recovered from the exception. The monitoring data shows only a CPU utilization surge and an increase in the number of active sessions. No slow SQL queries are recorded. In this case, you cannot find the root cause due to a lack of log data and scenario details. The same fault may occur again and impair the service availability.

Procedure

1. Log on to the DAS console.
2. In the left-side navigation pane, click Instance Monitoring.
3. On the Instance Monitoring page, find the database instance that you want to manage and choose Performance > Performance Snapshots in the Actions column.
4. On the Performance Snapshots page that appears, perform the following steps to set alert triggers or manually trigger the creation of performance snapshots.
   • Manually Trigger
     1. On the Performance Snapshots page, click Manual Triggering.
     2. In the Confirmation dialog box, click OK.
   • Enable Automatic Snapshot
     1. On the Performance Snapshots page, click.
     2. In the dialog box that appears, confirm the alert rules that trigger performance snapshots.
        • For a database instance that is not associated with alert templates, create an alert template or associate the instance with an alert template as prompted.
        • For a database instance that has an alert template associated, confirm the alert rule that triggers performance snapshots.
          Note If you want to edit the conditions that trigger performance snapshots, edit the alert rule as prompted.
     3. After you configure the alert rule, return to the Performance Snapshots page and click the Settings icon again. In the Enable Automatic Snapshot dialog box, click OK.

Performance snapshot

1. On the Performance Snapshots page, select the snapshot that you want to view and click Search in the Actions column.
2. The snapshot details page appears.
   • The Monitoring within Seconds section shows the monitoring data of key metrics based on seconds.
   • The section below Monitoring within Seconds shows the following tabs, which provide statistics collected for the first minute after the snapshot is triggered.
     • Session: shows active sessions of each second during the minute, which helps you identify the most frequently executed SQL statement, the most time-consuming SQL statement, top users, top sources, top commands, and top sessions.
     • Full SQL: shows the full request statistics collected within the minute. The statistics can be collected only after you enable the SQL Explorer feature.
     • Slow SQL
     • Error Logs