#!/usr/sbin/dtrace -s
/*
 * mysqld_pid_etime.d - measure mysqld query execution latency.
 *                     Written for Solaris 10 (needs DTrace).
 *
 * 01-Jun-2007, ver 0.50
 *
 * USAGE: ./mysqld_pid_etime.d -p `pgrep -x mysqld`
 *
 * This prints distribution plots of the elapsed time during the execution
 * of MySQL statements, with a plot for each query string traced. This
 * measure the execution stage only, not the parse or plan stages.
 *
 * This is written using the DTrace pid provider, which means it uses an
 * unstable interface and is likely to stop working for future versions of
 * mysql (this was tested on mysql-5.1.17-beta).
 *
 * 01-Jun-2007 Brendan Gregg   Created this.
 */

#pragma D option quiet

dtrace:::BEGIN
{
       printf("Tracing... Hit Ctrl-C to end.\n");
}

pid$target::*mysql_parse*:entry
{
       self->query = copyinstr(arg1);
}

pid$target::*mysql_execute_command*:entry
{
       self->start = timestamp;
}

pid$target::*mysql_execute_command*:return
/self->start/
{
       this->elapsed = timestamp - self->start;
       @time[self->query] = quantize(this->elapsed);
       self->query = 0;
       self->start = 0;
}

dtrace:::END
{
       printf("MySQL Query execution latency (ns):\n");
       printa(@time);
}
</