Re: PG function call

----- Original Message -----
From: "Alvaro Herrera" <alvherre@alvh.no-ip.org>
To: "smile khmer" <khmersmile@email.com>
Subject: Re: [HACKERS] PG function call
Date: Thu, 6 Oct 2005 10:30:37 -0400

>
> On Thu, Oct 06, 2005 at 09:06:59AM -0500, smile khmer wrote:
> > Dear all,
> >
> > Does anyone know how index searching work in PG. I've explored
> > the source code of PG, for btree, for searching, it will call the
> > functions in file btcompare.c. As I've made a printf in the
> > functions of the file btcompare.c. When I compile and run PG, it
> > get into loop,..... the messages are printed and printed .....
>
> Not a loop -- the function may just be called a lot of times.

but when I write the output to file (not standard out put), it won't finish, so I interupted and
there're more than 50.000 lines,...
and during the compiling process, there's alot of messages like these :
.............................
tsort: -: input contains a loop:
tsort: fe-misc.o
tsort: fe-exec.o
tsort: -: input contains a loop:
tsort: fe-misc.o
tsort: fe-exec.o
tsort: -: input contains a loop:
tsort: fe-misc.o
tsort: fe-exec.o
...
.....

>
> > I want to know how the function called happen in Postgres, it
> > seems that it doesn't call the function directly !
>
> The code gets function pointers through the catalogs, so they will be
> called even if you don't see a direct function call.  At some time the
> code will ask for the equality function for such-and-such datatype, then
> call it.
>

then, if I want to change somepart of the code or write one function which will tell postgresql to call this function
wheneverIt compares the string or character data type. I've found "citext" project but I still don't understand where
exactlyto modified code. 

thanks,
Moni
> --
> Alvaro Herrera                 http://www.amazon.com/gp/registry/CTMLCN8V17R4
> "Acepta los honores y aplausos y perderás tu libertad"
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