Re: A general Q about index

On Tue, Jul 16, 2013 at 7:00 PM, David Johnston <polobo(at)yahoo(dot)com> wrote:

> David Johnston wrote
> >
> > soroosh sardari wrote
> >> Hi
> >>
> >> I want to know how an index is created and used.
> >> actually if you can show to me a simple start point, it would be great.
> >>
> >> Regards,
> >> Soroosh Sardari
> > In the documentation there is a table of contents and listed on that
> table
> > is a section named "Indexes".
> >
> > David J.
>
> Since you posted this to hacker you may mean you wish to know how to
> program
> them as oppose to use them in SQL. I have no clue to this regard. If you
> did mean "use in SQL" then the documentation is your friend and you also
> should not have posted this question to -hackers but to -general instead;
> probably should have posted there anyway to begin with and been more clear
> as to what you mean by "created and used".
>
> David J.
>
>
>
>
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Actually I mean the index in the source code, I want to know how index is
used in the backend for
execution of some query.
sorry my question is a bit ambiguous,
I start to read "src/backend/access/index/genam.c", and I think maybe this
file is not good way to start.
let me write a bunch of question to illustrate my point,
-How create an index for a table with specified field
-How index is stored in a page
-what module is responsible to fetch and swap out index pages
-Is there a kind of abstract class for all variant of index?