Re: Ability to plug-in/override Decimal Handler ?

Il giorno gio, 30/07/2009 alle 15.12 -0400, Stef Telford ha scritto:
> Hey Everyone,
>     I haven't ever had much recourse to email the mailing list, as I am 
> mostly one of those ORM folks that uses the upper layer. Apologies in 
> advance for that ;) However, I have noticed that during bulk operations 
> (mostly instantiations) using the ORM that the decimal.Decimal is slow. 
> I mean 400seconds slow, when compared to using gmpy.mpq which ends up 
> running in 50seconds.
[snip]

Probably you already found out in the ML archives but the right way to
do this is to register a typecaster for the interested OIDS:

import gmpy
import psycopg2.extensions

psycopg2.extensions.MPQ = psycopg2.extensions.new_type(
	(1700,), "MPQ",
	lambda data, curs: gmpy.mpq(data))

psycopg2.extensions.register_type(psycopg2.extensions.MPQ)

where assigning the new type to psycopg2.extensions is customary and
"1700" is the OID of the decimal type in PostgreSQL. Note that I didn't
run the code so it can contain typos but should be enough to get you
started.

Hope this helps,
federico

-- 
Federico Di Gregorio                         http://people.initd.org/fog
Debian GNU/Linux Developer                                [email protected]
INIT.D Developer                                           fog-NGVKUo/i/[email protected]
  Those who do not study Lisp are doomed to reimplement it. Poorly.
                                     -- from Karl M. Hegbloom .signature

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