运行函数python的多个实例

Question

我有一个函数readLatestOp（），该函数与mongodb和sqlite交互。我想同时运行此函数的多个实例来测试我的并发控制机制。我该如何解决这个问题。所以我想调用readLatestOp（）10次，同时运行它们

def readLatestOp():

    try:

        account = raw_input("Enter the account ID: ")
        started = time.clock()

        calSTime = datetime.datetime.utcnow()
        print(calSTime)
        cursor = conn.execute("select * from SNAPSHOT_ISOLATION where DEST_ID = ? AND T_COMMIT ISNULL OR SOURCE_ID = ? and T_COMMIT ISNULL", (account, account))
        result = (cursor.fetchone())
        while time.clock() - started < 5 and result is not None:

            cursor = conn.execute("select * from SNAPSHOT_ISOLATION where DEST_ID = ? AND T_COMMIT ISNULL OR SOURCE_ID = ? and T_COMMIT ISNULL", (account, account))
            result = (cursor.fetchone())

        findLatest = db.accounts.find_one({"_id" :  account})
        calFTime = datetime.datetime.utcnow()
        print(calFTime)
    except ValueError as err:
        print(err)
        print('You entered a wrong error')
        sys.exit(1)

    if result is not None:
        print("Data not avaialable")
    else:
        return findLatest

Answer 1

您可以使用multiprocessing：

import multiprocessing

processes = []

for i in range(10):
   process = multiprocessing.Process(target=readLatestOp)
   processes.append(process)
   process.start()

print('10 processes started.')

for process in processes:
    process.join()

print('10 processes finished.')

展示：

import multiprocessing
import random
import time

def do_work(process_id):
    time.sleep( random.randint(1,10) )
    print '1 from process:', process_id
    time.sleep( random.randint(1,10) )
    print '2 from process:', process_id

processes = []

for i in range(3):
   process = multiprocessing.Process(target=do_work, args=[i])
   processes.append(process)
   process.start()

print('3 processes started.')

for process in processes:
    process.join()

print('3 processes finished.')

输出：

3 processes started.
1 from process: 2
2 from process: 2
1 from process: 1
2 from process: 1
1 from process: 0
2 from process: 0
3 processes finished.