Note
This variable is available starting with V2.2.77.
Description
tracefile_identifier specifies content to be added to logs to facilitate the filtering of line iteration tracking logs.
Privilege requirements
Query variables
systenants and all user tenants can execute theSHOW VARIABLESstatement or query theSYS.TENANT_VIRTUAL_SESSION_VARIABLEview (Oracle-compatible mode) or theinformation_schema.SESSION_VARIABLESview (MySQL-compatible mode) to view the values of Session system variables.Modify variables
systenants and all user tenants can directly modify the values of Session system variables in their own tenants.
Attributes
| Attribute | Description |
|---|---|
| Type | Varchar |
| Default value | Empty string |
| Scope | Session |
| Modifiable | Yes. You can execute the SET statement to modify the value. |
Usage
You can use the TRACING and STAT HINTs to instruct the executor to print the content of each row during the execution of an operator. To facilitate the search and identification of these contents, you can specify a string using tracefile_identifier and output it together with the row content to the log. For example, you can specify XXXYYYZZZ or MY_TRACE as the string.
Examples
Specify MY_TRACE as the string to output it together with the row content to the log for easy search.
obclient> SET tracefile_identifier = 'MY_TRACE';