Re: [SQLObject] Woven+Twisted

[Oisin M. <oi...@en...>]

Hi,

Brad Bollenbach wrote:

>On Tue, Aug 26, 2003 at 07:26:19PM +0100, Oisin Mulvihill wrote:
>[snip Ian's comments]
>  
>
>>Hi,
>>
>>I said this already but I've used twisted and sqlobject successfully. I use
>>    
>>
>
>Eh, it may *look* like you have. :) SQLObject is synchronous, Twisted
>is asynchronous, there's no compatibility here.
>
>e.g.
>
>Person.select("hair_colour = 'blonde'")
>  
>
Ho-ho very funny.

>In Twisted, every method call must return as fast as possible
>(basically, instantly). In the above .select() is at the mercy of how
>many blondes you have in your system. By extension, so is the rest of
>your code; nothing else will get executed until that .select() comes
>back.
>
>A deferred (in Twisted) doesn't solve this, because .select() doesn't
>know how to be asynchronous anyway so the code will block no matter
>what you try to do.
>  
>
Surely if it doesn't matter how long it takes to return in your system 
this isn't
going to be a problem.  In my situation the caller needs to know and 
will wait
for an answer. I don't see the problem but I've only been dealing with 
database
for about 6months or so, mainly small scale stuff which doesn't take long to
return.

>>twisted and sqlobject together in a call card top up system running on
>>a linux server, which has been running without problems for the past few
>>months.
>>    
>>
>
>Interesting, but dangerous. Rest assurred if your system encounters
>non-trivial load you'll need to rewrite it (by replacing SQLObject
>with adbapi in Twisted.)
>
I presume this mean loosing the ORM and going to a low level of 
generating the
sql queries. Are there other ORMs in which this wouldn't be a problem?

Would it be possible to do an sqlobject reactor for twisted. I mean at a 
low level the
database connections are socket connections. You could poll and read 
socket descriptors.
This would then allow you to have the asynchronous behaviour.
 
All the best,

om