p; return conn
def execute_under_lock(self,thread_id):
conn = self.get_conn()
lock = conn.lock(self._lock_resource, self._ttl)
if lock :
self.business_method(thread_id)
conn.unlock(lock)
else:
print("try later")
'''
模拟一个经典的不存在则插入，存在则更新,起多线程并发操作
实际中可能是一个非常复杂的需要独占性的原子性操作
'''
def business_method(self,thread_id):
print(" thread -----{0}------ execute business method begin".format(thread_id))
conn = pymssql.connect(host="127.0.0.1",server="SQL2014", port=50503, database="DB01")
cursor = conn.cursor()
id = random.randint(0, 100)
sql_script = ''' select 1 from TestTable where Id = {0} '''.format(id)
cursor.execute(sql_script)
if not(cursor.fetchone()):
sql_script = ''' insert into TestTable values ({0},{1},{1},getdate(),getdate()) '''.format(id,thread_id)
else:
sql_script = ''' update TestTable set LastUpdateThreadId ={0} ,LastUpdate = getdate() where Id = {1} '''.format(thread_id,id)
cursor.execute(sql_script)
conn.commit()
cursor.close()
conn.close()
print(" thread -----{0}------ execute business method finish".format(thread_id))
if __name__ == "__main__":
redis_servers = [{"host": "*.*.*.*","port": 9000,"db": 0},
{"host": "*.*.*.*","port": 9001,"db": 0},
{"host": "*.*.*.*","port": 9002,"db": 0},]
lock_resource = "mylock"
ttl = 2000 #毫秒
redlock_test = RedLockTest(_connection_list = redis_servers,_lock_resource=lock_resource, _ttl=ttl)
#redlock_test.execute_under_lock(redlock_test.business_method)
threads = []
for i in range(50):
#普通的并发模式调用业务逻辑的方法，会产生大量的主键冲突
#t = threading.Thread(target=redlock_test.business_method,args=(i,))
#Redis分布式锁控制下的多线程
t = threading.Thread(target=redlock_test.execute_under_lock,args=(i,))
threads.append(t)
begin_time = ctime()
for t in threads:
t.setDaemon(True)
t.start()
for t in threads:
t.join()
测试 1，简单多线程并发
简单地起多线程执行测试的方法，测试中出现两个很明显的问题
1，出现主键冲突（而报错）
2，从打印的日志来看，各个线程在测试的方法中存在交叉执行的情况（日志信息的交叉意味着线程的交叉执行）
测试 2，Re