On Unix, signals can be sent to processes. mysqld responds to signals sent to it as follows:
SIGTERMcauses the server to shut down.
SIGHUPcauses the server to reload the grant tables and to flush tables, logs, the thread cache, and the host cache. These actions are like various forms of the
FLUSHstatement. The server also writes a status report to the error log that has this format:
Status information: Current dir: /var/mysql/data/ Running threads: 0 Stack size: 196608 Current locks: Key caches: default Buffer_size: 8388600 Block_size: 1024 Division_limit: 100 Age_limit: 300 blocks used: 0 not flushed: 0 w_requests: 0 writes: 0 r_requests: 0 reads: 0 handler status: read_key: 0 read_next: 0 read_rnd 0 read_first: 1 write: 0 delete 0 update: 0 Table status: Opened tables: 5 Open tables: 0 Open files: 7 Open streams: 0 Alarm status: Active alarms: 1 Max used alarms: 2 Next alarm time: 67