Michael Bayer wrote: > > Christian Démolis wrote: >> Hello, >> >> I tried all the method to compare the different methods :
Here's a decorator I would advise using: http://stackoverflow.com/questions/1171166/how-can-i-profile-a-sqlalchemy-powered-application/1175677#1175677 Also I would advise testing this as well. Session.execute() creates a text() construct which does some regular expression matching that you don't need: engine.execute("update table set foo=bar") >> >> *TEST CODE* >> >> xref = time.time() >> self.UtilisateurCourant.Dispo = 1 >> session.merge(self.UtilisateurCourant, dont_load=True) >> session.flush() >> print "With ORM dont_load", time.time()-xref >> >> xref = time.time() >> >> session.query(Utilisateur).filter(Utilisateur.IdUtilisateur==self.UtilisateurCourant.IdUtilisateur).update({'Dispo':0}, >> False) >> print "With ORM force update", time.time()-xref >> >> xref = time.time() >> if self.UtilisateurCourant.IdUtilisateur: >> session.execute("UPDATE utilisateur SET Dispo=0 WHERE >> IdUtilisateur="+str(self.UtilisateurCourant.IdUtilisateur)) >> print "With ORM pure SQL", time.time()-xref >> >> import MySQLdb >> db = MySQLdb.connection(host="192.168.45.28", user="apm", >> passwd="apm", db="test_christian") >> xref = time.time() >> db.query("""UPDATE utilisateur SET Dispo=1 WHERE >> IdUtilisateur=1""") >> r = db.store_result() >> print "With MySQLdb without ORM", time.time()-xref >> >> >> *TEST RESULTS* >> >> With ORM dont_load 0.453000068665 >> With ORM force update 0.296999931335 >> With ORM pure SQL 0.31200003624 >> With MySQLdb without ORM 0.0939998626709 >> >> With ORM dont_load 0.452999830246 >> With ORM force update 0.297000169754 >> With ORM pure SQL 0.31200003624 >> With MySQLdb without ORM 0.0939998626709 >> >> With ORM dont_load 0.453000068665 >> With ORM force update 0.296999931335 >> With ORM pure SQL 0.31200003624 >> With MySQLdb without ORM 0.0940001010895 > > please use the profile module. The call chain from > Session.execute(somestring) down to connection.execute() is definitely not > three times slower than connection.execute() itself. On my workstation > here I can execute hundreds of ORM queries per second. > > >> >> >> 2009/9/30 Michael Bayer <mike...@zzzcomputing.com> >> >>> >>> Christian Démolis wrote: >>> > Thx for your answer. >>> > MakeReleased is a method of com object windows agent (self.agent = >>> > DispatchWithEvents('CosmoAgent.clsCCAgent', Evenement)) >>> > It takes 0 second to execute as we can see in the execute print >>> >>> yes I realized later there were two blocks of timer calls. The >>> inclusion >>> of that code made the example harder to read. >>> >>> In particular using session.merge() with an object will issue a SELECT >>> first to locate the current row. this is likely the cause of the >>> slowness in this specific case since you seem to have a slow network >>> (profiling would reveal this too). Passing "dont_load=True" to >>> merge() >>> will skip the SELECT step and trust that the state you are passing it >>> is >>> the state that is within the database. >>> >>> > "Orm does additional steps" >>> > is it possible to force him update only one attribute of the object? >>> >>> you may say: >>> >>> >>> session.query(MyObject).filter(some_criterion).update({'attrname':somenewvalue}, >>> False) >>> >>> which will issue an UPDATE statement matching the criterion. this is >>> the >>> fastest way by far using the ORM only. >>> >>> Changing the "False" to "evaluate" or "expire" will also update or >>> expire >>> the state of your ORM instance - but that will add some overhead. >>> >>> >>> >>> > >>> >> >> > >> > > > > > --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed to the Google Groups "sqlalchemy" group. To post to this group, send email to sqlalchemy@googlegroups.com To unsubscribe from this group, send email to sqlalchemy+unsubscr...@googlegroups.com For more options, visit this group at http://groups.google.com/group/sqlalchemy?hl=en -~----------~----~----~----~------~----~------~--~---
