Re: [SQLObject] caching an expensive property

[Oleg B. <ph...@ph...>]

Hi!

On Wed, Dec 10, 2014 at 12:47:17AM +0100, "Fetchinson ." <fet...@go...> wrote:
> What's the best strategy for some kind of caching of an expensive property?
> 
> Let's say I have the following:
> 
> class obj( SQLObject ):
>     somefield = StringCol( )
>     someotherfield = StringCol( )
> 
>     def _get_expensivestuff( self ):
>         # takes a long time
>         return result
> 
> And if my obj instance is alive for a long time and expensivestuff
> gets accessed many times I'd like to just compute result once, store
> it somewhere (where?) and return it from there.
> 
> I'm aware of memoizing the result of a function using a suitable
> decorator but I'm concerned about thread safety and I'm not terribly
> knowledgeable about the internals of sqlobject.
> 
> Any ideas would help a lot. Thanks,
> Daniel

   I hope you know that SQLObject converts _get_* and _set_* methods to
properties so you shouldn't decorate the methods. Also most caching
decorators are not thread-safe so you'd better implement your own
caching with proper locking.

Oleg.
-- 
     Oleg Broytman            http://phdru.name/            ph...@ph...
           Programmers don't die, they just GOSUB without RETURN.