Re: InsertPgAttributeTuple() and attcacheoff

On Tue, Aug 14, 2018 at 3:50 PM, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> wrote:
> Peter Eisentraut <peter(dot)eisentraut(at)2ndquadrant(dot)com> writes:
>> It seems to me that it would make sense if InsertPgAttributeTuple() were
>> to set attcacheoff to -1 instead of taking it from the caller.
>
> Looked this over, no objections.
>
> I wonder whether we should set that field to -1 when we *read*
> pg_attribute rows from disk, and be less fussed about what gets written
> out. The only real advantage is that this'd protect us from foolish
> manual changes to pg_attribute.attcacheoff entries, but that doesn't
> seem negligible.

I wouldn't object to forcibly writing in -1 when we read the data, but
I don't think it's a good idea to let values other than -1 get written
to the disk. User-visible random nonsense in system catalogs seems
like too much of a foot-gun to me.

--
Robert Haas
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