pymysql 连接池

  import pymysql
  from   pymysql.cursors import DictCursor
  from   queue import Queue
import threading
  class   Pool:
    def __init__(self,size, *args,** kwargs):
        self._size = size
        self._pool = Queue(size)
        self.local = threading.local()
          for  _  in   range(size):
            conn =pymysql.connect(*args,** kwargs)
            self._pool.put(conn)

    @property
    def size(self):
          return   self._pool.qsize()

    def acquire(self):
          return  self._pool. get  ()

    def release(self,conn:pymysql.connections.Connection):
          if   isinstance(conn,pymysql.connections.Connection):
            self._pool.put(conn)

    def __enter__(self):
          if  getattr(self.local, ‘  conn  ‘ ,None)  is   None:
            self.local.conn = self.acquire()
          return  self.local.conn.cursor(cursor= DictCursor)

    def __exit__(self,exc_type,exc_value,exc_tb):
          if   exc_type:
            self.local.conn.rollback()
          else  :
            self.local.conn.commit()
        self.release(self.local.conn)
        self.local.conn = None

pool =Pool( 5 , ‘  localhost  ‘ , ‘  root  ‘ , ‘  cruces  ‘ , ‘  uranus  ‘  )

with pool   as   cursor:
    with cursor:
        sql = ‘  select * from pp where id in (%(a)s,%(b)s,%(c)s)  ‘  
        cursor.execute(sql,{  ‘  a  ‘ : 3 , ‘  b  ‘ : 6 , ‘  c  ‘ : 7  })
        print(cursor.fetchall())
        sql = ‘  show processlist  ‘  
        cursor.execute(sql,args = None)
          for  b  in   cursor:
            print(b)

# conn = pool.acquire()
# print(conn)
# print(pool.size)
# cursor =conn.cursor(cursor= DictCursor)
# cursor.execute(  ‘  select * from pp  ‘  )
# # print(cursor.fetchall())
# pool.release(conn)
# print(pool.size)  

  import pymysql
  from   pymysql.cursors import DictCursor

conn = None
cursor = None
  try  :
    conn =pymysql.connect( ‘  localhost  ‘ , ‘  root  ‘ , ‘  cruces  ‘ , ‘  uranus  ‘  )
    print(conn.password)
    print(conn.ping(False))
    conn.__ent
    with conn.cursor(cursor =DictCursor)  as   cursor:
        d ={ ‘  id  ‘ : ‘  5 or 1  ‘  }
        sql = ‘  select * from pp where id=%(id)s  ‘  
        print(cursor.execute(sql,d))
        cursor.rownumber =- cursor.rowcount
        print(cursor.fetchone())

    cursor.execute(  ‘  select 1  ‘  )

    conn.commit()
# except:
#     conn.rollback()
  finally  :
      if   conn:
        conn.close()  

pymysql 连接池

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