You can trace all SQL going through both a database connection or query. Both the Database and Query objects have a debug() method. If you pass true to this method, then all SQL executed by the object will be printed to standard error before it is executed.

The value set on a database object is inherited by its queries. This if you enable debugging, then all queries subsequently created from that database object will have their debug flags turned on as well. Likewise, you can set debug states individually for queries by calling their respective debug methods.

# Enable tracing/debugging
db.debug true

# q1 has debugging on b/c it is set on db
q1 = db.query()

# Can turn it off:
q1.debug false

db.debug false

# q2 has debugging off
q2 = db.query()