# strace -p 20033 Process 20033 attached - interrupt to quit restart_syscall(<... resuming interrupted call ...>^C <unfinished ...> Process 20033 detached The below is from a system running a recent update of Debian/Testing. Running strace on process 20033 shows that it's stuck in a system call (see the above strace output). So it appears that one of the child threads of 20033 is using the CPU time. How do I determine which one it is? Does anyone have any general suggestions for debugging the case where mysqld is using a lot of CPU time while not doing anything? The mysql command "show processlist;" shows that there are currently NO connections to mysqld at all. top - 17:23:54 up 22:44, 2 users, load average: 1.22, 2.00, 2.59 Tasks: 191 total, 1 running, 190 sleeping, 0 stopped, 0 zombie %Cpu(s): 21.6 us, 2.6 sy, 0.0 ni, 75.0 id, 0.8 wa, 0.0 hi, 0.0 si, 0.0 st KiB Mem: 2034264 total, 1621676 used, 412588 free, 51228 buffers KiB Swap: 1949692 total, 66244 used, 1883448 free, 879412 cached PID USER PR NI VIRT RES SHR S %CPU %MEM TIME+ COMMAND 20033 mysql 20 0 344m 37m 1480 S 130.9 1.9 33:31.93 mysqld 27420 root 20 0 23300 1548 1084 R 5.9 0.1 0:00.02 top -- My Main Blog http://etbe.coker.com.au/ My Documents Blog http://doc.coker.com.au/