Re: Toward a column reorder solution

Nilson wrote:
> Quoting  "wiki.postgresql.org/wiki/Alter_column_position 
> <http://wiki.postgresql.org/wiki/Alter_column_position>" :
>
> "The idea of allowing re-ordering of column position is not one the 
> postgresql developers are against, it is more a case where no one has 
> stepped forward to do the work."
>
> Well, a hard journey starts with a single step.
>
> Why not, in the next release that requires to run initdb, add a 
> *attraw*  column (a better name is welcome) in the catalog that stores 
> the physical position of column forever, i.e., the same semantics of 
> *attnum*?
>
> Then, in a future release - 9.1 for example - the postgres team can 
> make  *attnum* changeable using something like ALTER COLUMN POSITION?
>
> Pros:
>
> - Requires only a couple of changes in main postgreSQL code. It seems 
> to be very simple.
>
> - Allows a smooth and decentralized rewrite of the whole code that may 
> needs the  *attraw *attribute - postgreSQL, contribs, pgAdmin, 
> drivers, tools  etc. 
> This will give time to developers of that code to detect the impact 
> of  semantics change, make the arrangements  necessary and also allow 
> the release of production level software using the new feature before 
> *attnum *becomes changeable.
> So, when *attnum *becomes read/write, all that software will be ready.
>
> Cons
>
> - More 4 bytes in each row of the catalog.
>
> Nilson


Please review the previous discussions on this. In particular, see this 
proposal from Tom Lane that I believe represents the consensus way we 
want to go on this: 
<http://archives.postgresql.org/pgsql-hackers/2006-12/msg00983.php>

cheers

andrew