Developing a custom MySQL connection pool

using third-party packages

https://pypi.python.org/pypi/DBUtils

TAR-ZXVF *.tar.gz * Python3 setup.py build && python3 setup.py Install

IMPORT TIMEIMPORT PYMYSQLIMPORT THREADINGFROM DBUTILS.POOLEDDB IMPORT POOLEDDB,  SHAREDDBCONNECTIONPOOL = POOLEDDB (    creator=pymysql,  #  The maximum number of connections allowed for modules     maxconnections=6,  #  connection pools using linked databases, 0 and none means no limit on the number of connections      mincached=2,  #  when initialized, the link pool creates at least idle links, 0 means no     maxcached=5 is created,   #  link pool up to idle links, 0 and none limit the number of links that are most shared in the     maxshared=3,  #  link pool, 0 and none means sharing all. ps:  useless, because the pymysql and MYSQLDB modules such as  threadsafety are 1, all values regardless of the number set to how much, _maxcached forever is 0, so forever is all links are shared.     blocking=True,  #  If there are no available connections in the connection pool, wait is blocked. True, wait; False, do not wait and then error     maxusage=None,  #  the number of times a link is reused, None means no limit      setsession=[],  #  a list of commands to execute before starting the session. such as: ["set datestyle to&nbsp, ....",  "set time zone  ..."]   &nbSp;ping=0,    # ping mysql Server, check if the service is available. #  such as: 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= ' 123 ',     database= ' pooldb ',     charset= ' UTF8 ') def func ():     #  detects if the number of currently running connections is less than the maximum number of links, if not less than: Waits or reports Raise toomanyconnections exceptions     #   Otherwise     #  gets the link  steadydbconnection in the link created when the initialization is first initialized.     #  then encapsulates the Steadydbconnection object into Pooleddedicateddbconnection and returns.     #  if the link you initially created is not linked, create a Steadydbconnection object and encapsulate it in pooleddedicateddbconnection and return.     #  once the link is closed, the connection is returned to the connection pool for subsequent threads to continue to use.     conn = pool.connection ()     # print (th,  ') Link was taken away ',  conn1._con)     # print (th,  ' pond now has ', pool._idle_cache,  ' \ r \ n ')     cursor = conn.cursor ()     cursor.execute (' Select  * from tb1 ')     result = cursor.fetchall ()       #并没有关闭, just put the connection back in the connection Pool     conn.close () func ()

Developing a custom MySQL connection pool