在用python写后端服务时候,需要与mysql数据库进行一些数据查询或者插入更新等操作。启动服务后接口运行一切正常, 隔了第二天去看服务日志就会报错,问题如下:
pymysql.err.OperationalError: (2006, "MySQL server has gone away (BrokenPipeError(32, 'Broken pipe'))")
MySQL默认的wait_timeout时间28800秒,即8小时,超过8小时,MySQL就会放弃连接。MySQL默认设置的时间是8小时,可以通过运行show variables like ‘%timeout%’;这个SQL即可查看到,时间根据自己业务而定。
因此,当第二天早上前端调用接口时候,mysql连接失败,无法获取数据或者更新数据。
最终采用连接池的方式避免出现这种问题,写一个操作数据库的工具函数,后续需要处理的时候直接调用即可。
定义连接池:
import os
import pymysql
import configparser
from DBUtils.PooledDB import PooledDB
MODULE_REAL_DIR = os.path.dirname(os.path.realpath(__file__))
config = configparser.ConfigParser()
config.read(MODULE_REAL_DIR + '/../conf/config.conf')
host = config.get('MYSQL_FORMAL_DB', 'host')
user = config.get('MYSQL_FORMAL_DB', 'user')
pwd = config.get('MYSQL_FORMAL_DB', 'pwd')
db = config.get('MYSQL_FORMAL_DB', 'db')
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空闲的链接,0表示不创建
maxcached=5, # 链接池中最多闲置的链接,0和None不限制
maxshared=1, # 链接池中最多共享的链接数量,0和None表示全部共享
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
maxusage=None, # 一个链接最多被重复使用的次数,None表示无限制
setsession=[], # 开始会话前执行的命令列表。如:["set datestyle to ...", "set time zone ..."]
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=host,
port=3306,
user=user,
password=pwd,
database=db,
charset='utf8'
)
定义基本操作:
from db_utils import POOL
import pymysql
def create_conn():
conn = POOL.connection()
# cursor = conn.cursor(pymysql.cursors.DictCursor)
cursor = conn.cursor()
return conn, cursor
def close_conn(conn, cursor):
conn.close()
cursor.close()
def select_one(sql, args):
conn, cur = create_conn()
try:
cur.execute(sql, args)
result = cur.fetchone()
close_conn(conn, cur)
return result
except Exception as e:
print("select one except ", args)
close_conn(conn, cur)
return None
def select_all(sql, args):
conn, cur = create_conn()
try:
cur.execute(sql, args)
result = cur.fetchall()
close_conn(conn, cur)
return result
except Exception as e:
print("select all except ", args)
close_conn(conn, cur)
return None
def insert_one(sql, args):
conn, cur = create_conn()
try:
result = cur.execute(sql, args)
conn.commit()
close_conn(conn, cur)
return True
except Exception as e:
print("insert except ", args)
conn.rollback()
close_conn(conn, cur)
return False
def delete_one(sql, args):
conn, cur = create_conn()
try:
result = cur.execute(sql, args)
conn.commit()
close_conn(conn, cur)
return True
except Exception as e:
print("delete except ", args)
conn.rollback()
close_conn(conn, cur)
return False
def update_one(sql, args):
conn, cur = create_conn()
try:
result = cur.execute(sql, args)
conn.commit()
close_conn(conn, cur)
return True
except Exception as e:
print("update except ", args)
conn.rollback()
return False