From: | Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
---|---|
To: | Manfred Koizar <mkoi-pg(at)aon(dot)at> |
Cc: | "Rod Taylor" <rbt(at)zort(dot)ca>, "Hiroshi Inoue" <Inoue(at)tpf(dot)co(dot)jp>, "Neil Conway" <nconway(at)klamath(dot)dyndns(dot)org>, pgsql-hackers(at)postgresql(dot)org |
Subject: | Re: Number of attributes in HeapTupleHeader |
Date: | 2002-05-08 20:54:16 |
Message-ID: | 12453.1020891256@sss.pgh.pa.us |
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Lists: | pgsql-hackers |
Manfred Koizar <mkoi-pg(at)aon(dot)at> writes:
> An ALTER TABLE statement makes a new copy of the metadata describing
> the table, modifies the copy and gives it a unique (for this table)
> version number. It does not change or remove old metadata.
This has been discussed before --- in PG terms, it'd mean keeping the
OID of a rowtype in the tuple header. (No, I won't let you get away
with a 1-byte integer. But you could remove natts and hoff, thus
buying back 3 of the 4 bytes.)
I was actually going to suggest it again earlier in this thread; but
people weren't excited about the idea last time it was brought up,
so I decided not to bother. It'd be a *lot* of work and a lot of
breakage of existing clients (eg, pg_attribute would need to link
to pg_type not pg_class, pg_class.relnatts would move to pg_type,
etc etc). The flexibility looks cool, but people seem to feel that
the price is too high for the actual amount of usefulness.
regards, tom lane
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