The query-start and
query-done probes are triggered when a
specific query is received by the server and when the query has
been completed and the information has been successfully sent to
the client.
query-start(query, connectionid, database, user, host) query-done(status)
query-start: Triggered after the query
string has been received from the client. The arguments are:
query: The full text of the submitted
query.
connectionid: The connection ID of
the client that submitted the query. The connection ID
equals the connection ID returned when the client first
connects and the Id value in the
output from SHOW
PROCESSLIST.
database: The database name on which
the query is being executed.
user: The username used to connect to
the server.
host: The hostname of the client.
query-done: Triggered once the query has
been executed and the information has been returned to the
client. The probe includes a single argument,
status, which returns 0 when the query is
successfully executed and 1 if there was an error.
You can get a simple report of the execution time for each query using the following D script:
#!/usr/sbin/dtrace -s
#pragma D option quiet
dtrace:::BEGIN
{
printf("%-20s %-20s %-40s %-9s\n", "Who", "Database", "Query", "Time(ms)");
}
mysql*:::query-start
{
self->query = copyinstr(arg0);
self->connid = arg1;
self->db = copyinstr(arg2);
self->who = strjoin(copyinstr(arg3),strjoin("@",copyinstr(arg4)));
self->querystart = timestamp;
}
mysql*:::query-done
{
printf("%-20s %-20s %-40s %-9d\n",self->who,self->db,self->query,
(timestamp - self->querystart) / 1000000);
}When executing the above script you should get a basic idea of the execution time of your queries:
shell> ./query.d Who Database Query Time(ms) root@localhost test select * from t1 order by i limit 10 0 root@localhost test set global query_cache_size=0 0 root@localhost test select * from t1 order by i limit 10 776 root@localhost test select * from t1 order by i limit 10 773 root@localhost test select * from t1 order by i desc limit 10 795