Without knowing too much about your code, the only thing I can say,
having had a similar issue, was that select_related witha specified
depth generally made for more efficient queries.
For fun, I started on some code to output database queries on all my
pages while I'm debugging:
<div id="django_debug">
<h2>Queries</h2>
<p>
{{ sql_queries|length }} Quer{{ sql_queries|pluralize:"y,ies" }}
{% ifnotequal sql_queries|length 0 %}
(<span style="cursor: pointer;" onclick="var
s=document.getElementById
('debugQueryTable').style;s.display=s.display=='none'?'':'none';this.innerHTML=this.innerHTML=='Show'?'Hide':'Show';">Show</
span>)
{% endifnotequal %}
</p>
<ol id="debugQueryTable" style="display: none;">
{% for query in sql_queries %}
<li class="{% cycle odd,even %}">{{ query.sql|wordwrap:40 }}
({{ query.time }})</li>
{% endfor %}
</ol>
</div>
I wrote this code when I was going through my site and making my
queries more efficient.
Another strategy that worked for me, is having an *ideal* SQL query
and then trying to fit that into the Django way of grabbing objects.
I already knew the most efficient query to use, so I had to just hack
around until Django did what I want.
Hope this helps.
On Dec 6, 8:56 pm, erikcw <[EMAIL PROTECTED]> wrote:
> Hi all,
>
> I'm trying to write a model query that will return a queryset along
> with the latest (and earliest) data from 2 related models.
>
> Right now I'm doing something like this:
>
> objects = Model1.objects.filter(user=3).select_related() #about 6,000
> objects
>
> data = {}
> for o in objects:
> data[o.name] = [o.field1, o.field2]
> data[o.name].append(o.field3.model2_set.all().latest('created'))
> #get latest row from related model2
> data[o.name].append(o.model3_set.all().order_by('created')[0])
> #get earliest row from related model3
>
> The problem is that this results in a TON of database queries. This
> view is taking over a minute to process. The select_related on the
> first line doesn't seem to be helping since I'm using latest()/
> order_by which generates a new query.
>
> How can I make this more efficient? Denormalizing the isn't an option
> since model2 and model 3 are many-to-one.
>
> Is there something I can do with extra() in the first query or some
> sort of subquey I can do to eliminate the loop?
>
> Thanks!
> Erik
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