impyla+multiprocessing crash example

example.py

import multiprocessing
import impala.dbapi

class Impala(obect):
    def __init__(self, host, database, port, username, password, lock=None):
        self.conn = impala.dbapi.connect(host=host,
                                         port=port,
                                         database=database,
                                         user=username,
                                         password=password,
                                         auth_mechanism='PLAIN',
                                         use_ssl=True)

        self.lock = lock or multiprocessing.Lock()

    def run_query(self, query):
        with self.lock:
            cur = self.conn.cursor()
            cur.execute(query)
            cur.close()

if __name__ == '__main__':
    queries = [] # some list of SQL queries
    lock = multiprocessing.Lock()
    impala = Impala(..., lock=lock)
    pool = multiprocessing.Pool(8)
    pool.map(impala.run_query, queries)
    pool.close()
    pool.join()