Forked from syrusakbary/django_efficient_queryset.py
Created
October 31, 2017 11:12
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Django efficient queryset iterator (by dividing in chunks). Taked from https://djangosnippets.org/snippets/1949/
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| import gc | |
| def queryset_iterator(queryset, chunksize=1000): | |
| ''''' | |
| Iterate over a Django Queryset ordered by the primary key | |
| This method loads a maximum of chunksize (default: 1000) rows in it's | |
| memory at the same time while django normally would load all rows in it's | |
| memory. Using the iterator() method only causes it to not preload all the | |
| classes. | |
| Note that the implementation of the iterator does not support ordered query sets. | |
| ''' | |
| pk = 0 | |
| last_pk = queryset.order_by('-pk')[0].pk | |
| queryset = queryset.order_by('pk') | |
| while pk < last_pk: | |
| for row in queryset.filter(pk__gt=pk)[:chunksize]: | |
| pk = row.pk | |
| yield row | |
| gc.collect() |
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