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wsantos/gist:8afe5b80a524e9af1d4b26bcf9b41ed8

Forked from hest/gist:8798884
Created May 21, 2018 15:16
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Fast SQLAlchemy counting (avoid query.count() subquery)
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gistfile1.py
def get_count(q):
count_q = q.statement.with_only_columns([func.count()]).order_by(None)
count = q.session.execute(count_q).scalar()
return count
q = session.query(TestModel).filter(...).order_by(...)
# Slow: SELECT COUNT(*) FROM (SELECT ... FROM TestModel WHERE ...) ...
print q.count()
# Fast: SELECT COUNT(*) FROM TestModel WHERE ...
print get_count(q)
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