Viewing and Downloading Slow Query Logs

Scenarios

Slow query logs record statements that exceed long_query_time (1 second by default). You can view log details 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.

Parameter Description

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 Databases > Relational Database Service.
4. On the Instances page, click the target DB instance.
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.
   • 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.
   • You can view slow query logs of a specified database name (which cannot contain any special characters). The database name supports only exact search.
   • Slow query logs only record executed statements whose execution duration exceeds the threshold.
   • 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. To view more slow log records, contact customer service.
   • If the length of a single line of an SQL statement exceeds 10 KB or the total number of lines exceeds 200, the SQL statement will be truncated. When you view slow query log details, the SQL statement may be incomplete after special processing and is for reference only.

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 Databases > Relational Database Service.
4. On the Instances page, click the target DB instance.
5. In the navigation pane, choose Logs. On the Slow Query Logs page, click the Downloads tab.
6. Locate a log file 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.

   • Only logs no more than 40 MB can be downloaded directly from this page. The time range is calculated from the time you download the logs back to the time when the accumulated file size reaches 40 MB.
   • It is impossible to generate a log file much larger than 40 MB, like 100 MB or 200 MB. If a log file that is a little larger than 40 MB is required, use OBS Browser+ to download it by referring to Method 1: Using OBS Browser+.
   • 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 download the log, click OK.
   • The downloaded logs contain only the logs of the primary node.