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dchaplinsky/sort_optimization.py

Created November 16, 2010 12:32
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Method to avoid heavy filesort
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sort_optimization.py
class FoobarManager(models.Manager):
def latest(self, limit=10):
""" more effecient version of query to avoid filesort """
ids = list(self.values_list('id', flat=True).order_by('-created')[:limit])
return self.filter(id__in=ids).extra(
select={'manual': 'FIELD(id,%s)' % ','.join(map(str, ids))},
order_by=['manual'])
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