On Mon, 9 Aug 2004, Hicham G. Elmongui wrote:
> Hi everybody,
> I never meant my emails to be spam. That's why i am just asking whether my
> questions here are out of subject. Typically my questions are about
> postgresql source code, like the question below. Please advise me whether
> i should forward my questions to somewhere else.
> Thanks a lot,
> --h
Most people are currently with beta and stuff.
>
>
> On Thu, 5 Aug 2004, Hicham G. Elmongui wrote:
>
> > In "join_selectivity" function (plancat.c), a function call is made to
> > "OidFunctionCall4" (fmgr.c), which in turn calls a function pointer.
> >
> > In need to know what is the actual function being called from
> > OidFunctionCall4 if the selectivity of mergejoin is the one required from
> > join_selectivity.
Connect to the backend with a debugger such as gdb and step through the
code and you will find it. Alternatively, have a better look at the code.
The function called is that returned by get_oprjoin(). This looks up the
operator (ie, '=', '<') in pg_operator and gets the function from there.
For example, '=' is eqjoinsel() from memory.
Gavin