aiopg execute_batch implementation

async_execute_batch.py

# coding: utf-8
'''Async implementation of psycopg2.extras.execute_batch, for use with aiopg.

async with aiopg.connect(...) as conn:
    async with conn.cursor() as cur:
        await execute_batch(cur, 'SELECT ...', args)
'''

def _paginate(seq, page_size):
    '''Consume an iterable and return it in chunks.
    Every chunk is at most `page_size`. Never return an empty chunk.
    '''
    page = []
    it = iter(seq)
    while True:
        try:
            for _ in range(page_size):
                page.append(it.next())
            yield page
            page = []
        except StopIteration:
            if page:
                yield page
            return


async def execute_batch(cur, sql, argslist, page_size=100):
    '''Execute groups of statements in fewer server roundtrips.
    '''
    for page in _paginate(argslist, page_size=page_size):
        sqls = [await cur.mogrify(sql, args) for args in page]
        await cur.execute(b';'.join(sqls))