sp_cycle_errorlog (Transact-SQL)
Applies to: 
SQL Server
Closes the current error log file and cycles the error log extension numbers just like a server restart. The new error log contains version and copyright information and a line indicating that the new log was created.
Transact-SQL syntax conventions
Syntax
sp_cycle_errorlog
[ ; ]
Arguments
None.
Return code values
0 (success) or 1 (failure).
Result set
None.
Remarks
Every time SQL Server is started, the current error log is renamed to errorlog.1; errorlog.1 becomes errorlog.2, errorlog.2 becomes errorlog.3, and so on. sp_cycle_errorlog enables you to cycle the error log files without stopping and starting the server.
Permissions
Execute permissions for sp_cycle_errorlog are restricted to members of the sysadmin fixed server role.
Examples
The following example cycles the SQL Server error log.
EXEC sp_cycle_errorlog;
GO