Django admin change-list optimizing query: select field1, field2 instead of select *

Question

I have a large horizontal table (30 fields) with quite a few foreign keys (each averaging upto 10 fields). While displaying the table in the Django admin, I use select related to optimize and avoid multiple querying. What I am looking for is to ensure that only my list_display entries are retrieved and not all the 30 fields + (foreign keys X 10) fields. Currently a select * on the table + a select * on all the join fields run. Basically, a way to get 'values' at the Django admin level. Thanks.

Edit: An example below:

class X(models.Model):
    x1 = models.IntegerField  # needed for admin display
    x2 = models.TextField     # needed for admin display
    x3 = models.ForeignKey(Y) 
    x4 = models.ForeignKey(Z)
    ...                       # X5 to x30 are not needed for admin display
    X30 = models.Integerfield

    @property
    def y1(self) :
        return self.x3.y1

    @property
    def y2(self):
        return self.x4.z1

class Y(models.Model):
    y1 = models.IntegerField  # needed for admin display
    ...
    y10 = models.IntegerField


class Z(models.Model):
    z1 = models.IntegerField  # needed for admin display
    ...                       # z2 to z10 are not needed for admin display
    z10 = models.IntegerField


**admin.py**
list_display = ['x1', 'x2', 'y1', 'z1']

My problem is when I look at the query generated to display this, it does a select * on X(x1 to x30), and using select_related, it extracts y1 to y10 and z1 to z10, even though I do not need all fields.

This table is heavily used as a CRM and it is currently a showstopper because of the slow query that is generated. There are also blobs and huge varchars, which are not used for the display and still being queried.

Thanks.

Are you looking for: http://stackoverflow.com/questions/291945/how-do-i-filter-foreignkey-choices-in-a-django-modelform or http://stackoverflow.com/questions/1824267/limit-foreign-key-choices-in-select-in-an-inline-form-in-admin — Williams, Oct 22 '12 at 07:50

score 0 · Answer 1 · answered Dec 11 '13 at 13:26

Remember that in your list_display block you can always replace x3 with x3_id to use the FK value you already have on hand and not do any extra lookup at all (ditch select_related altogether).

You could then combine that with custom functions for your list_display as outlined here to maybe replace those raw FK integers with hyperlinks to their own admin pages?

Django admin change-list optimizing query: select field1, field2 instead of select *

1 Answers1