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•As of MySQL 8.0.19, SIGUSR1  causes the server to flush the error log, general query log, and slow query log. One use for SIGUSR1  is to implement log rotation without having to connect to the server, which requires a MySQL account that has privileges sufficient for those operations. For information about log rotation, see Section 5.4.6, “Server Log Maintenance” . 

The server response to SIGUSR1  is a subset of the response to SIGHUP , enabling SIGUSR1  to be used as a more “lightweight”  signal that flushes certain logs without the other SIGHUP  effects such as flushing the thread and host caches and writing a status report to the error log. 

• SIGINT  normally is ignored by the server. Starting the server with the --gdb  option installs an interrupt handler for SIGINT  for debugging purposes. See Section 5.9.1.4, “Debugging mysqld under gdb” . 

## Client Response to Signals 

MySQL client programs respond to signals as follows: 

•The mysql  client interprets SIGINT  (typically the result of typing Control+C ) as instruction to interrupt the current statement if there is one, or to cancel any partial input line otherwise. This behavior can be disabled using the --sigint-ignore  option to ignore SIGINT  signals. 

•Client programs that use the MySQL client library block SIGPIPE  signals by default. These variations are possible: 

•Client can install their own SIGPIPE  handler to override the default behavior. See Writing C API Threaded Client Programs. 

•Clients can prevent installation of SIGPIPE  handlers by specifying the CLIENT_IGNORE_SIGPIPE option to mysql_real_connect()  at connect time. See mysql_real_connect(). 

