OK so I have solved this, the flaw being my understanding of the
cacheing of Django database QuerySets. I still have not eliminated
the double auth_user request because one is made in the
@login_required directive and the other is made in the view code to
pass user data to the template. However it is easy to see how in
Django:
# Set the course_id
course_id = enrollment.course.id
# Get the requested course
course = Course.objects.get(id__exact=course_id)
Will result in two separate queries to get the course with that id.
It can be solved easily with:
# Get requested course and set the course_id
course = enrollment.course.id
course_id = course.id
which reduces the number of SQL queries by 1 each page request or
shaves off about .4ms per page view.
-Matteius
On Nov 1, 1:24 pm, Matteius <matte...@gmail.com> wrote:
> In this case there is no form POST data so that code gets skipped. I
> started profiling with the django_debugger_toolbar and my SQL data
> results are at the bottom. There are duplicate SQL select statements
> for handin_course and auth_user which doesn't make sense to me as I
> understand how views should work ...
>
> #################################################
> # courseassignments - Course Assignments View
> #################################################
> @login_required
> def course_assignments(request, enrollment_id):
> # Request enrollment
> enrollment = Enrollment.objects.get(id__exact=enrollment_id)
>
> # Determine access level and create default behavior
> flag = verifyEnrollment(request, enrollment)
> template = loader.get_template('handin/course_blocked.html')
> context = RequestContext(request, {"user": request.user, "flag":
> flag} )
>
> # If access is granted
> if flag == 1:
> # If we have post data process the form
> if request.POST:
>
> # Determine if submission is late
> assignment =
> Assignment.objects.get(id__exact=request.POST['assignment'])
> onTime = True
> try:
> # First see if there is a due date override
> dueDate =
> DueDateOverride.objects.filter(enrollment=enrollment.id).filter(assignment=assignment.id)
> [0]
> if
> isLateNow( adjustDateDays( adjustDateWeeks(enrollment.start_date,
> dueDate.weeks_after), dueDate.days_after)):
> onTime = False
> except IndexError:
> # If not, see if there is a global due date
> if assignment.apply_due_date:
> if
> isLateNow( adjustDateDays( adjustDateWeeks(enrollment.start_date,
> assignment.weeks_after), assignment.days_after)):
> onTime = False
>
> instance = Submission(enrollment_id=enrollment.id,
> assignment_id=request.POST['assignment'], on_time=onTime)
> newSubmission = SubmissionForm(request.POST, request.FILES,
> instance=instance)
> newSubmission.save()
> return
> HttpResponseRedirect(reverse('classcomm.handin.views.course_assignments',
> args=(enrollment.id,)))
>
> # Set the course_id
> course_id = enrollment.course.id
>
> # Get the requested course
> course = Course.objects.get(id__exact=course_id)
>
> # Find the assignments for the requested course
> assignments = Assignment.objects.all().filter(course=course_id)
>
> # Find the grades for the current enrollment
> grades = Grade.objects.all().filter(enrollment=enrollment.id)
>
> # Find the submissions for the current enrollment
> submissions =
> Submission.objects.all().filter(enrollment=enrollment.id)
>
> # Find the due date overrides for the current enrollment
> dueDateOverrides =
> DueDateOverride.objects.all().filter(enrollment=enrollment.id)
>
> # Create assignmentDataList for easy template cycle
> # [Assignment, current Submission, current Grade, current
> DueDateOverride]
> assignmentDataList = list()
> for assignment in assignments:
> # Find the submission
> currentSubmission = None
> for submission in submissions:
> if submission.assignment_id == assignment.id:
> currentSubmission = submission
> # Find the grade
> currentGrade = None
> for grade in grades:
> if grade.assignment_id == assignment.id:
> currentGrade = grade
> # Find a due date override
> currentDDO = None
> for dueDateOverride in dueDateOverrides:
> if dueDateOverride.assignment_id == assignment.id:
> currentDDO = dueDateOverrides
> # Add the tupple to a list
> assignmentDataList.append( (assignment, currentSubmission,
> currentGrade, currentDDO) )
>
> # Create an assignment submission form
> form = SubmissionForm()
>
> # Set template; Create context
> template = loader.get_template('handin/course_assignments.html')
> context = RequestContext(request, {"user": request.user,
> "course": course, "form": form,
> "enrollment": enrollment, "assignmentDataList":
> assignmentDataList} )
>
> # Return page view
> return HttpResponse( template.render(context) )
> # End Def
>
> SQL Queries
> Time (ms) Action Stacktrace Query
> 0.61 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `django_session`.`session_key`,
> `django_session`.`session_data`, `django_session`.`expire_date` FROM
> `django_session` WHERE (`django_session`.`session_key` =
> 97bf63456064cb8d5682f762a4d7faef AND `django_session`.`expire_date` >
> 2010-11-01 11:55:14 )
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 0.46 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `auth_user`.`id`, `auth_user`.`username`,
> `auth_user`.`first_name`, `auth_user`.`last_name`,
> `auth_user`.`email`, `auth_user`.`password`, `auth_user`.`is_staff`,
> `auth_user`.`is_active`, `auth_user`.`is_superuser`,
> `auth_user`.`last_login`, `auth_user`.`date_joined` FROM `auth_user`
> WHERE `auth_user`.`id` = 1
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 0.30 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `handin_enrollment`.`id`, `handin_enrollment`.`student_id`,
> `handin_enrollment`.`course_id`, `handin_enrollment`.`start_date`,
> `handin_enrollment`.`enrollment_length`,
> `handin_enrollment`.`access_mode`, `handin_enrollment`.`mentor_id`
> FROM `handin_enrollment` WHERE `handin_enrollment`.`id` = 3
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 181 course_assignments /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 0.29 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `auth_user`.`id`, `auth_user`.`username`,
> `auth_user`.`first_name`, `auth_user`.`last_name`,
> `auth_user`.`email`, `auth_user`.`password`, `auth_user`.`is_staff`,
> `auth_user`.`is_active`, `auth_user`.`is_superuser`,
> `auth_user`.`last_login`, `auth_user`.`date_joined` FROM `auth_user`
> WHERE `auth_user`.`id` = 1
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 184 course_assignments /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 395 verifyEnrollment /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 0.34 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `handin_course`.`id`, `handin_course`.`department_id`,
> `handin_course`.`name`, `handin_course`.`director_id`,
> `handin_course`.`open_enrollments`,
> `handin_course`.`enrollment_length`, `handin_course`.`description`
> FROM `handin_course` WHERE `handin_course`.`id` = 2
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 184 course_assignments /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 405 verifyEnrollment /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 0.24 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `handin_course`.`id`, `handin_course`.`department_id`,
> `handin_course`.`name`, `handin_course`.`director_id`,
> `handin_course`.`open_enrollments`,
> `handin_course`.`enrollment_length`, `handin_course`.`description`
> FROM `handin_course` WHERE `handin_course`.`id` = 2
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 216 course_assignments /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 19.62 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `handin_assignment`.`id`, `handin_assignment`.`course_id`,
> `handin_assignment`.`name`, `handin_assignment`.`details`,
> `handin_assignment`.`points_possible`,
> `handin_assignment`.`display_points_possible`,
> `handin_assignment`.`provided_files`,
> `handin_assignment`.`apply_due_date`,
> `handin_assignment`.`weeks_after`, `handin_assignment`.`days_after`,
> `handin_assignment`.`allow_late`,
> `handin_assignment`.`disable_submissions` FROM `handin_assignment`
> WHERE `handin_assignment`.`course_id` = 2
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 233 course_assignments /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 8.19 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `handin_submission`.`id`, `handin_submission`.`enrollment_id`,
> `handin_submission`.`assignment_id`, `handin_submission`.`date`,
> `handin_submission`.`file`, `handin_submission`.`on_time`,
> `handin_submission`.`add_checkscript` FROM `handin_submission` WHERE
> `handin_submission`.`enrollment_id` = 3
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 236 course_assignments /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 9.72 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `handin_grade`.`id`, `handin_grade`.`enrollment_id`,
> `handin_grade`.`assignment_id`, `handin_grade`.`points_earned`,
> `handin_grade`.`returned_files`, `handin_grade`.`comments` FROM
> `handin_grade` WHERE `handin_grade`.`enrollment_id` = 3
> Line Method File
> 132 _worker build/bdist.linux-i686/egg/flup/server/threadpool.py
> 669 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 705 process_input build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 805 _do_params build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 789 _start_request build/bdist.linux-i686/egg/flup/server/
> fcgi_base.py
> 574 run build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 1159 handler build/bdist.linux-i686/egg/flup/server/fcgi_base.py
> 241 course_assignments /home2/geekshac/django_projects/classcomm/
> handin/views.py
> 17.95 SELECT
> EXPLAIN
>
> Toggle Stacktrace
>
> SELECT `handin_duedateoverride`.`id`,
> `handin_duedateoverride`.`enrollment_id`,
> `handin_duedateoverride`.`assignment_id`,
> `handin_duedateoverride`.`weeks_after`,
> `handin_duedateoverride`.`days_after`,
> `handin_duedateoverride`.`allow_late` FROM `handin_duedateoverride`
> WHERE `handin_duedateoverride`.`enrollment_id` = 3
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