Operation Scenarios

An SQL statement query that takes more time than the specified value is referred to as a "slow query", and the corresponding statement is called a "slow query statement". The process where a database administrator (DBA) analyzes slow query statements and finds out the reasons why slow queries occur is known as "slow query analysis".

You can view the slow log details, error log details, rollback logs of an instance and download slow logs on the operation log page in the console. You can also view and download database logs on the command line interface (CLI) or through TencentDB APIs. For more information, please see Querying Backup Log and Querying Binary Log.

Note：

TencentDB for MySQL (excluding the Basic Edition) instances support operation log management.

Notes on slow queries in MySQL

• long_query_time: slow query threshold parameter down to the microsecond level. The default value is 10s. When an SQL statement takes more time to execute, it will be recorded in a slow log.
  When the long_query_time parameter is adjusted, existing slow logs will not be affected. For example, if the slow log threshold parameter is 10s, slow logs will be reported for exceeding queries; after this value is modified to 1s, the previously reported logs will still be displayed.
• log_queries_not_using_indexes: whether to log unindexed queries. Default value: OFF.

Directions

1. Log in to the TencentDB for MySQL Console. In the instance list, click an instance name or Manage in the "Operation" column to enter the instance management page.
2. Go to the Operation Log tab, where you can view the slow log details, error log details, and rollback logs of the instance and download slow logs.

   Feature	Description
   Slow log details	Records SQL statements that took more than 10s to execute in the database in the last month
   Slow log download	Provides slow logs to download
   Error log details	Records logs of database execution errors
   Rollback log	Records the status and progress of rollback tasks

   
3. On the Download slow log tab, you can click Download in the "Operation" column to download slow logs.
4. In the pop-up dialog box, download the logs in one of the following ways:

   Note：

   Logs with a size of 0 KB cannot be downloaded.

   Method 1. Click Download to download directly.
   Method 2. Copy the download address, log in to a Linux CVM instance in the same VPC as the TencentDB instance, and use the wget command for download.

   Note：

   wget command format: wget -c 'log file download address' -O custom filename.log
   Below is an example:

   wget -c 'http://szx.dl.cdb.tencentyun.com:303/cfdee?appid=1210&time=1591&sign=aIGM%3D' -O test.log