Python数据库连接池DBUtils.PooledDB

import DBUtils.PersistentDBpersist=DBUtils.PersistentDB.PersistentDB(dbpai=MySQLdb,maxusage=1000,**kwargs)

db=pooled.connection()cur=db.cursor()cur.execute(sql)res=cur.fetchone()cur.close() # or del curdb.close() # or del db

import MySQLdbconn= MySQLdb.connect(host='localhost',user='root',passwd='pwd',db='myDB',port=3306)cur=conn.cursor()SQL="select * from table1"r=cur.execute(SQL)r=cur.fetchall()cur.close()conn.close()

import MySQLdbfrom DBUtils.PooledDB import PooledDBpool = PooledDB(MySQLdb,5,host='localhost',user='root',passwd='pwd',db='myDB',port=3306) #5为连接池里的最少连接数conn = pool.connection() #以后每次需要数据库连接就是用connection（）函数获取连接就好了cur=conn.cursor()SQL="select * from table1"r=cur.execute(SQL)r=cur.fetchall()cur.close()conn.close()

import sysimport threadingimport MySQLdbimport DBUtils.PooledDBconnargs = { ", "db":"test" }def test(conn): try: cursor = conn.cursor() count = cursor.execute("select * from users") rows = cursor.fetchall() for r in rows: pass finally: conn.close()def testloop(): print ("testloop") for i in range(1000): conn = MySQLdb.connect(**connargs) test(conn)def testpool(): print ("testpool") pooled = DBUtils.PooledDB.PooledDB(MySQLdb, **connargs) for i in range(1000): conn = pooled.connection() test(conn)def main(): t = testloop if len(sys.argv) == 1 else testpool for i in range(10): threading.Thread(target = t).start()if __name__ == "__main__": main()

$ time ./main.pytestlooptestlooptestlooptestlooptestlooptestlooptestlooptestlooptestlooptestloopreal 0m4.471suser 0m0.570ssys 0m4.670s$ time ./main.py -ltestpooltestpooltestpooltestpooltestpooltestpooltestpooltestpooltestpooltestpoolreal 0m2.637suser 0m0.320ssys 0m2.750s

DBUtils.PooledDB.PooledDB(self, creator, mincached=0, maxcached=0, maxshared=0, maxconnections=0, blocking=False, maxusage=None, setsession=None, failures=None, *args, **kwargs)Docstring: Set up the DB-API 2 connection pool. creator: either an arbitrary function returning new DB-API 2 connection objects or a DB-API 2 compliant database module mincached: initial number of idle connections in the pool (0 means no connections are made at startup) maxcached: maximum number of idle connections in the pool (0 or None means unlimited pool size) maxshared: maximum number of shared connections (0 or None means all connections are dedicated) When this maximum number is reached, connections are shared if they have been requested as shareable. maxconnections: maximum number of connections generally allowed (0 or None means an arbitrary number of connections) blocking: determines behavior when exceeding the maximum (if this is set to true, block and wait until the number of connections decreases, otherwise an error will be reported) maxusage: maximum number of reuses of a single connection (0 or None means unlimited reuse) When this maximum usage number of the connection is reached, the connection is automatically reset (closed and reopened). setsession: optional list of SQL commands that may serve to prepare the session, e.g. ["set datestyle to ...", "set time zone ..."] failures: an optional exception class or a tuple of exception classes for which the connection failover mechanism shall be applied, if the default (OperationalError, InternalError) is not adequate args, kwargs: the parameters that shall be passed to the creator function or the connection constructor of the DB-API 2 module