Maybe because the database is in Tunisia and my Computer in France.
I don t use sqlite, i use MySQL.
I just did a test on internet in Tunisia, 39kbits/sec upload and
417kbits/sec
2009/10/1 Michael Bayer <mike...@zzzcomputing.com>
>
> Christian Démolis wrote:
> > With debug mode it seems to take 0.15 second, my timer print 0.45 s
> > i don t know why this difference?
> >
> > 2009-10-01 17:00:38,586 INFO sqlalchemy.engine.base.Engine.0x...7f50
> > UPDATE
> > utilisateur SET `Dispo`=%s WHERE utilisateur.`IdU
> > tilisateur` = %s
> > 2009-10-01 17:00:38,586 INFO sqlalchemy.engine.base.Engine.0x...7f50 [0,
> > 1L]
> > 2009-10-01 17:00:38,743 INFO sqlalchemy.engine.base.Engine.0x...7f50
> > COMMIT
> > With ORM force update 0.453000068665
>
> On my workstation which is an intel mac, I can run 1000
> Session.execute("update...") against a sqlite memory db statements in .15
> seconds, using the simple time.time() approach to measure. The sqlite
> cursor directly, which is against an empty table so is insanely fast, can
> run 1000 in .01 seconds, so that is .14 seconds of overhead within SQLA.
>
> In your case, you're getting .2-.3 seconds of overhead just for *one*
> statement, subtracting what your database call takes natively. Meaning
> that while I can execute around 8000 Session.execute() statements per
> second, you can execute less than five. That seems very strange.
>
>
>
>
> >
> > 2009/10/1 Michael Bayer <mike...@zzzcomputing.com>
> >
> >>
> >> 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
-~----------~----~----~----~------~----~------~--~---
