int2[] vs int2vector in pg_catalog?

[Fabien COELHO]

Dear hackers,

I'm wondering for the rationnal of the types used in various tables in
pg_catalog (v 7.4.2) so as to represent the very same thing:

- in pg_index, the indkey is represented by a int2vector

- in pg_constraint, conkey and confkey are represented my smallint[]

As I was trying to compare the two, I have to resort to some hacks.

It also appears that there are very few available function to deal with
int2vector at the SQL or PL/pgSQL level. Basically I found none:-(

Any comments?

[Tom Lane]

Post by Fabien COELHO
I'm wondering for the rationnal of the types used in various tables in

History and backwards compatibility, mostly.

Post by Fabien COELHO
From the standpoint of the backend I don't think there is any

fundamental reason why we couldn't change pg_index.indkey and indclass
into varlena arrays, but I'd be worried about breaking existing
client-side code that looks at those columns. In particular the
question of whether indexing starts at 0 or 1 would be nasty.

regards, tom lane

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