Re: column ordering, was Re: [PATCHES] Enums patch v2 - Mailing list pgsql-hackers

From Zeugswetter Andreas ADI SD
Subject Re: column ordering, was Re: [PATCHES] Enums patch v2
Date
Msg-id E1539E0ED7043848906A8FF995BDA57901A34F65@m0143.s-mxs.net
Whole thread Raw
In response to Re: column ordering, was Re: [PATCHES] Enums patch v2  (Tom Lane <tgl@sss.pgh.pa.us>)
List pgsql-hackers
> >> You could make a case that we need *three* numbers: a permanent
column
> >> ID, a display position, and a storage position.
>
> > Could this not be handled by some catalog fixup after an add/drop?
If we
> > get the having 3 numbers you will almost have me convinced that this

> > might be too complicated after all.
>
> Actually, the more I think about it the more I think that 3 numbers
> might be the answer.  99% of the code would use only the permanent ID.

I am still of the opinion, that the system tables as such are too
visible
to users and addon developers as to change the meaning of attnum.

And I don't quite see what the point is. To alter a table's column you
need
an exclusive lock, and plan invalidation (or are you intending to
invalidate only
plans that reference * ?). Once there you can just as well fix the
numbering.
Yes, it is more work :-(

Andreas


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