如何退出Python多处理循环?
我有一个多处理代码,用于搜索数据库记录中的特定条件,当它到达数据库的末尾时,循环必须停止,我如何才能做到这一点?代码如下:如何退出Python多处理循环?,python,multiprocessing,Python,Multiprocessing,我有一个多处理代码,用于搜索数据库记录中的特定条件,当它到达数据库的末尾时,循环必须停止,我如何才能做到这一点?代码如下: import psycopg2 from multiprocessing import Pool conn = psycopg2.connect(a database) query=conn.cursor() query.execute(some query) def scanfile(): try: row=query.fetchone() excep
import psycopg2
from multiprocessing import Pool
conn = psycopg2.connect(a database)
query=conn.cursor()
query.execute(some query)
def scanfile():
try: row=query.fetchone()
except: return False #here the loop must stop
#do something with row...
if __name__=='__main__':
pool=Pool()
while True:
pool.apply_async(scanfile)
pool.close()
pool.join()
将查询/光标移到iterable上,让多处理为您分配工作
import psycopg2
from multiprocessing import Pool
def scanfile(row):
#do something with row...
if __name__ == '__main__':
conn = psycopg2.connect(a database)
query = conn.cursor()
query.execute(some query)
pool = Pool()
pool.map_async(scanfile, query).wait()
pool.close()
pool.join()
将查询/光标移到iterable上,让多处理为您分配工作
import psycopg2
from multiprocessing import Pool
def scanfile(row):
#do something with row...
if __name__ == '__main__':
conn = psycopg2.connect(a database)
query = conn.cursor()
query.execute(some query)
pool = Pool()
pool.map_async(scanfile, query).wait()
pool.close()
pool.join()
这听起来是个坏主意。检查到目前为止,它正在工作,它抓住行并用它做事情,但程序从未完成。这听起来是个坏主意。检查到目前为止它正在工作,它抓住行并用它做事情,但程序永远不会完成。