数据库链接池之threading.local线程版

线程标识ident

import threading
from threading import get_ident

def task():
ident = get_ident()
print(ident)
for i in range(20):
t = threading.Thread(target=task)
t.start()

数据库链接池之threading.local线程版

import pymysql
import threading
from concurrent.futures import ThreadPoolExecutor
from DBUtils.PooledDB import PooledDB

class SqlHelper(object):
def init(self):
self.pool = PooledDB(
creator=pymysql, # 使用链接数据库的模块
maxconnections=6, # 连接池允许的最大连接数，0和None表示不限制连接数
mincached=2, # 初始化时，链接池中至少创建的链接，0表示不创建
blocking=True, # 连接池中如果没有可用连接后，是否阻塞等待。True，等待；False，不等待然后报错
ping=0, # ping MySQL服务端，检查是否服务可用。
# 如：0 = None = never, 1 = default = whenever it is requested,
# 2 = when a cursor is created, 4 = when a query is executed, 7 = always
host='127.0.0.1',
port=3306,
user='root',
password='123456',
database='flask',
charset='utf8'
)
self.local = threading.local()

def open(self):
conn = self.pool.connection()
cursor = conn.cursor(pymysql.cursors.DictCursor)
return conn, cursor

def close(self, conn, cursor):
cursor.close()
conn.close()

def fetchall(self, sql, *args):
conn, cursor = self.open()
cursor.execute(sql, args)
conn.commit()
result = cursor.fetchall()
self.close(conn, cursor)
return result

def fetchone(self, sql, *args):
conn, cursor = self.open()
cursor.execute(sql, args)
conn.commit()
result = cursor.fetchone()
self.close(conn, cursor)
return result

def insert(self, sql, *args):
conn, cursor = self.open()
cursor.execute(sql, *args)
conn.commit()
result = cursor.fetchall()
self.close(conn, cursor)
return result

def enter(self):
conn, cursor = self.open()
rv = getattr(self.local, 'stack', None)
if not rv:
self.local.stack = [(conn, cursor), ]
else:
rv.append((conn, cursor))
self.local.stack = rv
return cursor

def exit(self, exc_type, exc_val, exc_tb):
rv = getattr(self.local, 'stack', None)
if not rv:
# del self.local.stack
return
conn, cursor = self.local.stack.pop()
cursor.close()
conn.close()

db = SqlHelper()

def task(n):
with db as cursor:
cursor.execute('select 1')
return n

多线程版

for i in range(10):
t = threading.Thread(target=task, args=(i,))
t.start()

线程池版

with ThreadPoolExecutor(max_workers=10) as t:
t.submit(task, 1)

数据库链接池threading.local其他用法

import pymysql
import threading
from DBUtils.PooledDB import PooledDB

POOL = PooledDB(
creator=pymysql, # 使用链接数据库的模块
maxconnections=6, # 连接池允许的最大连接数，0和None表示不限制连接数
mincached=2, # 初始化时，链接池中至少创建的链接，0表示不创建
blocking=True, # 连接池中如果没有可用连接后，是否阻塞等待。True，等待；False，不等待然后报错
ping=0,
# ping MySQL服务端，检查是否服务可用。# 如：0 = None = never, 1 = default = whenever it is requested, 2 = when a cursor is created, 4 = when a query is executed, 7 = always
host='127.0.0.1',
port=3306,
user='root',
password='222',
database='cmdb',
charset='utf8'
)

class SqlHelper(object):
def init(self):
self.conn = None
self.cursor = None

def open(self):
conn = POOL.connection()
cursor = conn.cursor()
return conn, cursor

def close(self):
self.cursor.close()
self.conn.close()

def enter(self):
self.conn,self.cursor = self.open()
return self.cursor

def exit(self, exc_type, exc_val, exc_tb):
self.close()

################### 使用 ##################

with SqlHelper() as c1:
c1.execute('select 1')
with SqlHelper() as c2:
c2.execute('select 2')
print(666)

with SqlHelper() as cursor:
cursor.execute('select 1')

with SqlHelper() as cursor:
cursor.execute('select 1')