MySQL 5.7 Reference Manual Including MySQL NDB Cluster 7.5 and NDB Cluster 7.6
The threadstat table provides a rough
snapshot of statistics for threads running in the
NDB kernel.
The threadstat table contains the following
columns:
node_id
Node ID
thr_no
Thread ID
thr_nm
Thread name
c_loop
Number of loops in main loop
c_exec
Number of signals executed
c_wait
Number of times waiting for additional input
c_l_sent_prioa
Number of priority A signals sent to own node
c_l_sent_priob
Number of priority B signals sent to own node
c_r_sent_prioa
Number of priority A signals sent to remote node
c_r_sent_priob
Number of priority B signals sent to remote node
os_tid
OS thread ID
os_now
OS time (ms)
os_ru_utime
OS user CPU time (µs)
os_ru_stime
OS system CPU time (µs)
os_ru_minflt
OS page reclaims (soft page faults)
os_ru_majflt
OS page faults (hard page faults)
os_ru_nvcsw
OS voluntary context switches
os_ru_nivcsw
OS involuntary context switches
os_time uses the system
gettimeofday() call.
The values of the os_ru_utime,
os_ru_stime, os_ru_minflt,
os_ru_majflt, os_ru_nvcsw,
and os_ru_nivcsw columns are obtained using
the system getrusage() call, or the
equivalent.
Since this table contains counts taken at a given point in time, for best results it is necessary to query this table periodically and store the results in an intermediate table or tables. The MySQL Server's Event Scheduler can be employed to automate such monitoring. For more information, see Section 23.4, “Using the Event Scheduler”.