Thread: [SQLObject] Connection instance ignored ?
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From: Stef T. <st...@um...> - 2009-02-08 23:16:05
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Hey Oleg, Everyone,
So, I have currently subclassed SQLObject to MySQLObject, as I am
trying to basically do one connection to a slave, another to a master.
Hopefully, that makes sense so far. In my class I have subclassed get
and select to use an existing connection. Eg;
> @classmethod
> def select(self, clause=None, **kwargs):
> ''' All selects should go through the slave connection '''
> global slaveConnection
> if slaveConnection:
> kwargs['connection']=slaveConnection
> return super(CompassObject, self).select(clause, **kwargs)
and the same for 'get' as well.. the curious thing is, I am still
seeing about 190 connects/disconnects on the postgreSQL side. Now,
since a connection is costly (believe me, it is ;), how can I get
these down to (in theory) 1. I know that may seem unrealistic, but
still, there shouldn't be 190 connects/disconnects.
This -is- a single threaded environment, I do print out during the
select in main.py and the connection -is- the same (same memory ref),
I don't use selectBy either.
I am kind of scratching my head here. Could it be that the joins
in the class don't honor the classes connection ? (would be kind of
strange and not at all what I would expect.. nor do I see that the
code is creating a new connection).
Any thoughts/ideas gratefully welcomed ;)
Regards
Stef
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From: Oleg B. <ph...@ph...> - 2009-02-09 14:44:14
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On Sun, Feb 08, 2009 at 06:16:01PM -0500, Stef Telford wrote:
> seeing about 190 connects/disconnects on the postgreSQL side. Now,
> since a connection is costly (believe me, it is ;), how can I get
> these down to (in theory) 1. I know that may seem unrealistic, but
> still, there shouldn't be 190 connects/disconnects.
>
> This -is- a single threaded environment, I do print out during the
> select in main.py and the connection -is- the same (same memory ref),
> I don't use selectBy either.
>
> I am kind of scratching my head here. Could it be that the joins
> in the class don't honor the classes connection?
Whatever joins use - they use SQLObject's DBConnection objects that are
high-level wrapper around Python DB API connections. Every DBConnection
instance maintains a pool of opened DB API connections and opens a new
DB API connection only if the pool is empty (the first query or all DB API
connections are busy in other threads). Hence there shouldn't be
connects/disconnects, especially in a single-threaded program.
The only way to make implicit connects/disconnects is to disable
connection pooling. You haven't done that, have you? connection._pool is
not None?
Oleg.
--
Oleg Broytmann http://phd.pp.ru/ ph...@ph...
Programmers don't die, they just GOSUB without RETURN.
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From: Stef T. <st...@um...> - 2009-02-09 17:35:49
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Oleg Broytmann wrote:
> On Sun, Feb 08, 2009 at 06:16:01PM -0500, Stef Telford wrote:
>> seeing about 190 connects/disconnects on the postgreSQL side.
>> Now, since a connection is costly (believe me, it is ;), how can
>> I get these down to (in theory) 1. I know that may seem
>> unrealistic, but still, there shouldn't be 190
>> connects/disconnects.
>>
>> This -is- a single threaded environment, I do print out during
>> the select in main.py and the connection -is- the same (same
>> memory ref), I don't use selectBy either.
>>
>> I am kind of scratching my head here. Could it be that the joins
>> in the class don't honor the classes connection?
>
> Whatever joins use - they use SQLObject's DBConnection objects that
> are high-level wrapper around Python DB API connections. Every
> DBConnection instance maintains a pool of opened DB API connections
> and opens a new DB API connection only if the pool is empty (the
> first query or all DB API connections are busy in other threads).
> Hence there shouldn't be connects/disconnects, especially in a
> single-threaded program. The only way to make implicit
> connects/disconnects is to disable connection pooling. You haven't
> done that, have you? connection._pool is not None?
>
> Oleg.
Hello again Oleg,
Actually, I -have- done this.. both with and without it seems to
make no difference, I still get a tonne of connections :(. I have
tried doing;
> slaveConnection = getConnectionURI() slaveConnection._pool = None
I have also tried specifically changing dbconnection.py self._pool
= [] to self._pool = None .. no joy there either :(
If I am doing something wrong, feel free to smack me upside the
head and tell me ;) I am inheriting inside myclass from SQLObject, I
am passing in the single connection via the overloaded get, _init and
select/selectBy (not that I use selectBy but.. yes)
Regards
Stef
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From: Oleg B. <ph...@ph...> - 2009-02-09 17:50:38
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On Mon, Feb 09, 2009 at 12:35:47PM -0500, Stef Telford wrote:
> slaveConnection._pool = None
It must be exactly opposite:
slaveConnection._pool = []
Well, an empty list is the default value, so by default SQLObject should
not disconnect but use a low-level connection from the pool.
Oleg.
--
Oleg Broytmann http://phd.pp.ru/ ph...@ph...
Programmers don't die, they just GOSUB without RETURN.
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From: Stef T. <st...@um...> - 2009-02-09 18:04:03
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Oleg Broytmann wrote:
> Oh, BTW, do you use transactions? And call transaction.commit()?
>
> Oleg.
Hello again Oleg,
Nope, well, I mean I -plan- to, but currently, the connection is
being made at the start of the page and then I go through get'ting and
init'ing objects. There isn't even any saving done, this is purely
rendering content stage. Also, if I print out the memory location,
it's always the same throughout the entire page rendering (eg; 8f000c).
I don't see why/how wrapping everything in a transaction would
change things.. but then.. that's jst me :)
Regards
Stef
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From: Oleg B. <ph...@ph...> - 2009-02-09 18:08:51
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On Mon, Feb 09, 2009 at 01:03:53PM -0500, Stef Telford wrote:
> Oleg Broytmann wrote:
> > Oh, BTW, do you use transactions? And call transaction.commit()?
> >
> I don't see why/how wrapping everything in a transaction would
> change things.. but then.. that's jst me :)
Transaction object in SQLObject closes the connection on commit. To
prevent it to do so call
transaction.commit(close=False)
But you don't use transactions, so I am out of ideas.
Oleg.
--
Oleg Broytmann http://phd.pp.ru/ ph...@ph...
Programmers don't die, they just GOSUB without RETURN.
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From: Oleg B. <ph...@ph...> - 2009-02-09 17:57:33
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Oh, BTW, do you use transactions? And call transaction.commit()?
Oleg.
--
Oleg Broytmann http://phd.pp.ru/ ph...@ph...
Programmers don't die, they just GOSUB without RETURN.
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