Struggling with slow startup / SQL in new app (using raw SQL)

Hi all,

Fairly new to Django. I ended up pulling out all of the ORM-generated queries and writing my own SQL directly (I got fed up trying to work out how to achieve the kind of things I needed without Django adding in extra joins or unintended WHERE clauses etc). All my app's SQL uses cursor.execute() and the dictfetchall() method as referenced here. 

I've found that my app incurs a couple of seconds load time in production, with CPU time at 2532ms and overall time 4684ms (according to the debug toolbar). I'm seeing 8 SQL queries take 380ms, and each one seems to be several times slower when made by Django versus hitting the database through phpMyAdmin or something: eg, this query:

SELECT * FROM news 

JOIN news_categories ON news.news_category_id = news_categories.id 

LEFT JOIN writers ON news.writer_id = writers.id 

LEFT JOIN images ON news.image_id = images.id 

ORDER BY news.is_sticky DESC, news.date_posted DESC 

LIMIT 10

This takes 14.8ms when run in phpMyAdmin (against the production database) but Django reports it as 85.2ms. The same ratios are true for all my other queries.

All I can think of is the note on the dictfetchall() method in the Django docs which describes a "small performance hit". Is this it?!

I've profiled the app too, although I'm a bit hazy about what it all means. Here's a dump of the result: http://pastebin.com/raw.php?i=UHE9edVC (this is from running on my local server rather than production but performance is broadly similar).

Can anyone help me? I realise I've perhaps gone off-piste by writing raw SQL but I feel it was justified.

thanks,

Matt

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