Viewing and Downloading Slow Query LogsViewing Slow Query Logs

Scenarios

Slow query logs record statements that exceed the long_query_time value (1 second by default). You can view log details and statistics to identify statements that are executing slowly and optimize the statements. You can also download slow query logs for service analysis.

Slow query logs generated within the last month can be viewed.

RDS supports the following types of statements: All types, SELECT, INSERT, UPDATE, DELETE, CREATE, CALL, ALTER, TRUNCATE, RENAME, FLUSH, EXPLAIN, LOCK, GRANT, REVOKE, COMMIT, ROLLBACK, DROP, and WITH.

Viewing Log Details

1. Log in to the management console.
2. Click in the upper left corner and select a region and a project.
3. Click in the upper left corner of the page and choose Database > Relational Database Service.
4. On the Instances page, click the target instance name to go to the Basic Information page.
5. In the navigation pane on the left, choose Logs. On the Slow Query Logs page, click Log Details to view details about slow query logs.
   • You can view the slow query log records of a specified execution statement type or a specific time period.
   • The Scanned Rows column indicates the number of data rows that are actually accessed and processed during SQL execution.
   • Only SELECT statements return the number of result rows. The number of result rows for the INSERT, UPDATE, DELETE, and CREATE statements is 0 by default.
   • The slow query log records only statements that have been executed and whose execution time exceeds the threshold. Statements still in progress are not logged.
   • The long_query_time parameter determines when a slow query log is recorded. However, changes to this parameter do not affect already recorded logs. If long_query_time is changed from 1s to 0.1s, RDS starts recording statements that meet the new threshold and still displays the previously recorded logs that do not meet the new threshold. For example, a 1.5s SQL statement that was recorded when the threshold was 1s will not be deleted now that the new threshold is 2s.
   • A maximum of 2,000 slow log records can be displayed.

Downloading a Slow Query Log

1. Log in to the management console.
2. Click in the upper left corner and select a region and a project.
3. Click in the upper left corner of the page and choose Database > Relational Database Service.
4. On the Instances page, click the target instance name to go to the Basic Information page.
5. In the navigation pane on the left, choose Logs. On the Slow Query Logs tab page, click Downloads. In the log list, locate a log whose status is Preparation completed and click Download in the Operation column.
   • The system automatically loads the downloading preparation tasks. The loading duration is determined by the log file size and network environment.
     • When the log is being prepared for download, the log status is Preparing.
     • When the log is ready for download, the log status is Preparation completed.
     • If the preparation for download fails, the log status is Abnormal.

     Logs in the Preparing or Abnormal status cannot be downloaded.

   • The download link is valid for 5 minutes. After the download link expires, a message is displayed indicating that the download link has expired. If you need to redownload the log, click OK.
   • The downloaded log file contains only the logs of the primary node.

Enabling Slow Log Reporting to LTS

1. Log in to the management console.
2. Click in the upper left corner and select a region and a project.
3. Click in the upper left corner of the page and choose Database > Relational Database Service.
4. On the Instances page, click the target instance name to go to the Basic Information page.
5. In the navigation pane, click Logs. On the Slow Query Logs page, click Log Details.
6. Click next to Report Slow Logs to LTS.
7. Select an LTS log group and log stream and click OK.