RE: AW: AW: [HACKERS] Getting OID in psql of recent insert

>
> > They get the location they ask for, or a failure. Hunting around for
> > the new tuple seems like a real waste, and if someone vacuums, it is
> > gone, no?
>
> It is probably worse, since they might even get the wrong row,
> but that's the same in Informix and Oracle.
>
> In Informix:
>
> a: selects rowid
> b: updates row, row grows, does not fit in page, is relocated
> c: inserts rows, pysical location of rowid is reused
> a: selects row by rowid, gets differet row --> bummer
>

In my implementation,scan by old(updated) tupleid fails.
For example,

=> create table t (dt int4);
CREATE
=> insert into t values (1);
INSERT 18601 1
=> select ctid,* from t;
ctid |dt
-----+--
(0,1)| 1
(1 row)

=> select * from t where ctid='(0,1)';
dt
--
1
(1 row)

=> update t set dt=2;
UPDATE 1
=> select * from t where ctid='(0,1)';
dt
--
(0 rows)

In order to get new tids,I provided functions currtid() and currtid2().

=> select currtid2('t','(0,1)');
currtid2
--------
(0,2)
(1 row)

=> select * from t where ctid='(0,2)';
dt
--
2
(1 row)

Of cource,this function is not effective after vacuum.
If you want to detect the change by vacuum,keep oids together with tids.

Regards.

Hiroshi Inoue
Inoue(at)tpf(dot)co(dot)jp