python使用多线程查询数据库的实现示例

#!/usr/bin/python
# -*- coding=utf-8 -*-
import time
import threading
import MySQLdb
import Queue
from MySQLdb.cursors import DictCursor
from DBUtils.PooledDB import PooledDB

def mysql_connection():
  host = 'localhost'
  user = 'root'
  port = 3306
  password = '123456'
  db = 'test'
  charset = 'utf8'
  limit_count = 3 # 最低预启动数据库连接数量
  pool = PooledDB(MySQLdb, limit_count, maxconnections=15, host=host, user=user, port=port, passwd=password, db=db, charset=charset,
      use_unicode=True, cursorclass=DictCursor)
  return pool


start = time.time()
pool = mysql_connection()

for id in range(50):
  con = pool.connection()
  cur = con.cursor()
  sql = '''select id,name,age,weight from test where id = %s '''%id
  cur.execute(sql)
  time.sleep(0.5)
  result = cur.fetchall()
  if result:
    print('this is tread %s (%s,%s,%s,%s)'%(id,result[0]['id'],result[0]['name'],result[0]['age'],result[0]['weight']))
  else:
    print('this tread %s result is none'%id)

end = time.time() - start
print(end)

#!/usr/bin/python
# -*- coding=utf-8 -*-
import time
import threading
import MySQLdb
import Queue
from MySQLdb.cursors import DictCursor
from DBUtils.PooledDB import PooledDB

def mysql_connection():
  host = 'localhost'
  user = 'root'
  port = 3306
  password = '123456'
  db = 'test'
  charset = 'utf8'
  limit_count = 3 # 最低预启动数据库连接数量
  pool = PooledDB(MySQLdb, limit_count, maxconnections=15, host=host, user=user, port=port, passwd=password, db=db, charset=charset,
      use_unicode=True, cursorclass=DictCursor)
  return pool

def tread_connection_db(id):
  con = pool.connection()
  cur = con.cursor()
  sql = '''select id,name,age,weight from test where id = %s '''%id
  cur.execute(sql)
  time.sleep(0.5)
  result = cur.fetchall()
  if result:
    print('this is tread %s (%s,%s,%s,%s)'%(id,result[0]['id'],result[0]['name'],result[0]['age'],result[0]['weight']))
  else:
    print('this tread %s result is none'%id)
  con.close()


if __name__=='__main__':
  start = time.time()
  #创建线程连接池，最大限制15个连接
  pool = mysql_connection()
  #创建队列，队列的最大个数及限制线程个数
  q=Queue.Queue(maxsize=10)
  #测试数据，多线程查询数据库
  for id in range(50):
    #创建线程并放入队列中
    t = threading.Thread(target=tread_connection_db, args=(id,))
    q.put(t)
    #队列队满
    if q.qsize()==10:
      #用于记录线程，便于终止线程
      join_thread = []
      #从对列取出线程并开始线程，直到队列为空
      while q.empty()!=True:
        t = q.get()
        join_thread.append(t)
        t.start()
      #终止上一次队满时里面的所有线程
      for t in join_thread:
        t.join()
  end = time.time() - start
  print(end)