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Fast SQLAlchemy counting (avoid query.count() subquery)
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| 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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