22 lines
627 B
Python
22 lines
627 B
Python
def windowed_query(query, column, window_size):
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""""
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Break a Query into chunks on a given column.
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see: https://github.com/sqlalchemy/sqlalchemy/wiki/RangeQuery-and-WindowedRangeQuery
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"""
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single_entity = query.is_single_entity
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query = query.add_columns(column).order_by(column)
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last_id = None
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while True:
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sub_query = query
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if last_id is not None:
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sub_query = sub_query.filter(column > last_id)
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chunk = sub_query.limit(window_size).all()
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if not chunk:
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break
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last_id = chunk[-1][-1]
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for row in chunk:
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yield row
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