def __iter__(self):
max_value = self.max_value
if self.min_value is not None:
cur_value = self.min_value
elif not self.sorted:
cur_value = 0
else:
cur_value = None
num = 0
limit = self.limit
queryset = self.queryset
if max_value:
queryset = queryset.filter(**{'%s__lte' % self.order_by: max_value})
# Adjust the sort order if we're stepping through reverse
if self.sorted:
if self.desc:
queryset = queryset.order_by('-%s' % self.order_by)
else:
queryset = queryset.order_by(self.order_by)
# we implement basic cursor pagination for columns that are not unique
last_value = None
offset = 0
has_results = True
while ((max_value and cur_value <= max_value) or has_results) and (not self.limit or num < self.limit):
start = num
if cur_value is None:
results = queryset
elif self.desc:
results = queryset.filter(**{'%s__lte' % self.order_by: cur_value})
elif not self.desc:
results = queryset.filter(**{'%s__gte' % self.order_by: cur_value})
results = results[offset:offset + self.step].iterator()
# hash maps to pull in select_related columns
if self.select_related:
# we have to pull them all into memory to do the select_related
results = list(results)
for fkey in self.select_related:
if '__' in fkey:
fkey, related = fkey.split('__')
else:
related = []
attach_foreignkey(results, getattr(self.queryset.model,
fkey, related))
if self.callbacks:
results = list(results)
for callback in self.callbacks:
callback(results)
for result in results:
yield result
num += 1
cur_value = getattr(result, self.order_by)
if cur_value == last_value:
offset += 1
else:
# offset needs to be based at 1 so we dont return a row
# that was already selected
last_value = cur_value
offset = 1
if (max_value and cur_value >= max_value) or (limit and num >= limit):
break
if cur_value is None:
break
has_results = num > start
def __iter__(self):
max_id = self.max_id
if self.min_id is not None:
at = self.min_id
elif not self.sorted:
at = 0
else:
at = None
num = 0
limit = self.limit or max_id
queryset = self.queryset
# Adjust the sort order if we're stepping through reverse
if self.sorted:
if self.desc:
queryset = queryset.order_by('-id')
else:
queryset = queryset.order_by('id')
if self.max_id:
queryset = queryset.filter(id__lte=max_id)
has_results = True
while ((max_id and at <= max_id) or has_results) and (not self.limit or num < self.limit):
start = num
if at is None:
results = queryset
elif self.desc:
results = queryset.filter(id__lte=at)
elif not self.desc:
results = queryset.filter(id__gte=at)
results = results[:self.step].iterator()
# We treat select_related as a special clause if it's passed, and do a hash-join
# at the application level for each chunk of results
if self.select_related:
results = list(results)
for fkey in self.select_related:
# TODO: We only handle one level of nesting
if '__' in fkey:
fkey, related = fkey.split('__')
else:
related = []
attach_foreignkey(results, getattr(self.queryset.model, fkey, related))
# Callbacks operate on a buffered chunk
if self.callbacks:
results = list(results)
for callback in self.callbacks:
callback(results)
for result in results:
yield result
num += 1
at = result.id
if (max_id and result.id >= max_id) or (limit and num >= limit):
break
if at is None:
break
has_results = num > start
if self.desc:
at -= 1
else:
at += 1
