<p>好吧,这是对我自己帖子的回复。干得好我=D</p>
<p>使我的系统从单核线程到四核多处理的速度提高了大约150%。在</p>
<pre><code>import multiprocessing, time, psycopg2
class Consumer(multiprocessing.Process):
def __init__(self, task_queue, result_queue):
multiprocessing.Process.__init__(self)
self.task_queue = task_queue
self.result_queue = result_queue
def run(self):
proc_name = self.name
while True:
next_task = self.task_queue.get()
if next_task is None:
print 'Tasks Complete'
self.task_queue.task_done()
break
answer = next_task()
self.task_queue.task_done()
self.result_queue.put(answer)
return
class Task(object):
def __init__(self, a):
self.a = a
def __call__(self):
pyConn = psycopg2.connect("dbname='geobase_1' host = 'localhost'")
pyConn.set_isolation_level(0)
pyCursor1 = pyConn.cursor()
procQuery = 'UPDATE city SET gid_fkey = gid FROM country WHERE ST_within((SELECT the_geom FROM city WHERE city_id = %s), country.the_geom) AND city_id = %s' % (self.a, self.a)
pyCursor1.execute(procQuery)
print 'What is self?'
print self.a
return self.a
def __str__(self):
return 'ARC'
def run(self):
print 'IN'
if __name__ == '__main__':
tasks = multiprocessing.JoinableQueue()
results = multiprocessing.Queue()
num_consumers = multiprocessing.cpu_count() * 2
consumers = [Consumer(tasks, results) for i in xrange(num_consumers)]
for w in consumers:
w.start()
pyConnX = psycopg2.connect("dbname='geobase_1' host = 'localhost'")
pyConnX.set_isolation_level(0)
pyCursorX = pyConnX.cursor()
pyCursorX.execute('SELECT count(*) FROM cities WHERE gid_fkey IS NULL')
temp = pyCursorX.fetchall()
num_job = temp[0]
num_jobs = num_job[0]
pyCursorX.execute('SELECT city_id FROM city WHERE gid_fkey IS NULL')
cityIdListTuple = pyCursorX.fetchall()
cityIdList = []
for x in cityIdListTuple:
cityIdList.append(x[0])
for i in xrange(num_jobs):
tasks.put(Task(cityIdList[i - 1]))
for i in xrange(num_consumers):
tasks.put(None)
while num_jobs:
result = results.get()
print result
num_jobs -= 1
</code></pre>
<p>现在我有另一个问题,我已经贴在这里了:</p>
<p><a href="https://stackoverflow.com/questions/7555680/create-db-connection-and-maintain-on-multiple-processes-multiprocessing">Create DB connection and maintain on multiple processes (multiprocessing)</a></p>
<p>希望我们能摆脱一些开销,让这个孩子更快。在</p>