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Re: [Dbdpg-general] benchmarking old Pg and DBD::Pg

From: Vlad <marchenko(at)gmail(dot)com>
To: Brandon Metcalf <bmetcalf(at)nortel(dot)com>
Cc: dbdpg-general(at)gborg(dot)postgresql(dot)org,pgsql-interfaces(at)postgresql(dot)org
Subject: Re: [Dbdpg-general] benchmarking old Pg and DBD::Pg
Date: 2005-04-08 18:12:31
Message-ID: cd70c6810504081112694ba268@mail.gmail.com (view raw or flat)
Thread:
Lists: pgsql-interfaces
Hi there,

we've noticed that too here and quick explanation is - with the new
"prepare" implementation, the query get prepared on the server side,
which is good; the problem is that all of the bind values passed to
the sql server during execute call are in form of ***varchar***, i.e.
even if a field is of int type in postgresql table, DBD::Pg passes
your bind value as char - as a result, postgresql doesn't use indexes.

I don't know if developers of new DBD::Pg have some game plan to fix
this problem... but it won't be easy: since perl is a no-var-type
language, so either DBD::Pg needs to analyze the table columns data
types first before executing a query and then use correct type for
bind values, or let coder pass those types explicitly... though I'm
not aware of a method in DBI that would let them do that...

Anyone from DBD::Pg can comment this please?

I was going to post an example to the list later today.

On Apr 8, 2005 12:30 PM, Brandon Metcalf <bmetcalf(at)nortel(dot)com> wrote:
> Has anyone done any benchmarking between the old Pg interface and
> DBI/DBD::Pg?  I have two versions of some code one of which uses Pg
> and the other DBI/DBD::Pg and the latter appears to cause much more of
> load on the system where it's running than the former.  However, I
> haven't done any benchmarking to support this claim.
> 
> --
> Brandon
> _______________________________________________
> Dbdpg-general mailing list
> Dbdpg-general(at)gborg(dot)postgresql(dot)org
> http://gborg.postgresql.org/mailman/listinfo/dbdpg-general
> 


-- 

Vlad

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