Real-Time Top SQL

Scenarios

Real-Time Top SQL shows the top SQL statements by resource overhead, helping you identify performance problems and optimize SQL statements.

To use the Real-Time Top SQL function, contact customer service.

The statistics come from the data in the kernel cache after the instance was started last time. When new SQL statements are executed, the data in the cache is updated synchronously. You can refresh the top SQL statement list to view the latest data.

If your instance is rebooted, the data in the cache will be lost, and the top SQL statements will be recalculated.

Procedure

1. Log in to the management console.
2. Click in the upper left corner and select a region.
3. Click in the upper left corner of the page and choose Databases > Relational Database Service.
4. On the Instances page, click the DB instance name.
5. In the navigation pane, choose DBA Assistant > Real-Time Diagnosis.
6. On the Real-Time Top SQL tab page, view the top SQL statements by CPU overhead, execution duration, rows returned, and logical reads.
   Figure 1 Real-Time Top SQL
   
   • To export details about top SQL statements, click .
   • To sort parameter values in the top SQL details, click in the table header.

7. To enable auto-refresh for the Real-Time Top SQL page, click Auto Refresh. You can choose to auto-refresh the page every 5s, 10s, or 15s.
   Figure 2 Auto Refresh
   

Parameter Description

• Top SQL statements by resource overhead: Top SQL statements are displayed by CPU overhead, execution duration, rows returned, and logical reads. You can also check the top SQL statements by average overhead and total overhead.
  Figure 3 Average overhead
  
  Figure 4 Total overhead
  

  Table 1 Parameter description for top SQL statements by resource overhead

  Parameter	Description
  CPU Overhead	CPU time consumed for executing a SQL statement, in milliseconds.
  Execution Duration	Execution duration of a SQL statement, in milliseconds.
  Rows Returned	Number of rows returned after a SQL statement is executed.
  Logical Reads	Logical reads executed by a SQL statement.

• Top SQL statement list
  Figure 5 Top SQL statement list
  

  Table 2 Parameter description for top SQL statement list

  Parameter	Description
  ID	A binary hash value calculated for the query. IDs are used to identify queries with similar logic.
  Statement	SQL statement. To view details, click the statement name.
  SQL Text	Text of the SQL statement block. To view details, click the text name.
  Database	Database where the SQL statement was executed.
  Executions	Total executions of the SQL statement.
  Total CPU Time	Total CPU overhead.
  Average CPU Time	Average CPU overhead.
  Total Execution Duration	Total execution duration.
  Avg. Execution Duration	Average execution duration.
  Total Rows Returned	Total number of returned rows.
  Avg. Rows Returned	Average number of returned rows.
  Total Logical Reads	Total logical read overhead.
  Avg. Logical Reads	Average logical read overhead.