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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 and statistics to identify statements that are executing slowly and optimize the statements. You can also download slow query logs for service analysis.

RDS supports the following statement types:
  • SELECT
  • INSERT
  • UPDATE
  • DELETE
  • CREATE

Parameter Description

Table 1 Parameters related to MySQL slow queries

Parameter

Description

long_query_time

Specifies the time greater than or equal to which slow query logs are recorded. The precision is microsecond. The default value is 1s. When the execution time of an SQL statement exceeds the value of this parameter, the SQL statement is recorded in slow query logs.

The recommended value is 1s. Note: The lock wait time is not calculated into the query time.

log_queries_not_using_indexes

Specifies whether to record the slow query without indexes. The default value is OFF.

log_throttle_queries_not_using_indexes

Specifies the SQL statement that can be written to the slow query log every minute. The default value is 0.

Showing Original Logs

  • To enable the function of showing original slow query logs, you need to contact customer service to apply for permission.
  • After the function of showing original logs is enabled, it cannot be disabled.
  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click Service List. Under Database, click Relational Database Service. The RDS console is displayed.
  4. On the Instance Management 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 and then click .
  6. In the displayed dialog box, click OK to enable the display of original slow query logs.

    Original slow query logs will be automatically deleted 30 days later after the function of showing original logs is enabled.

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 Service List. Under Database, click Relational Database Service. The RDS console is displayed.
  4. On the Instance Management 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.
    • 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, none of the previously recorded logs that do not meet the new threshold are deleted. 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.

Viewing Statistics

  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click Service List. Under Database, click Relational Database Service. The RDS console is displayed.
  4. On the Instance Management page, click the target DB instance.
  5. In the navigation pane on the left, choose Logs. On the Slow Query Logs page, click Statistics to view details.

    • On the Statistics page, only one of the SQL statements of the same type is displayed as an example. For example, if two select sleep(N) statements, select sleep(1) and select sleep(2), are executed in sequence, only select sleep(1) will be displayed.
    • 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, none of the previously recorded logs that do not meet the new threshold are deleted. 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.

Downloading a Log

  1. Log in to the management console.
  2. Click in the upper left corner and select a region and a project.
  3. Click Service List. Under Database, click Relational Database Service. The RDS console is displayed.
  4. On the Instance Management page, click the target DB instance.
  5. In the navigation pane on the left, choose Logs. On the Slow Query Logs page, click Download. 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.
      • During the downloading preparation, the log status is Preparing.
      • After the downloading preparation is complete, the log status is Preparation completed.
      • If the downloading preparation 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 download the log, click OK.

Parent topic: Log Management