Re: _bt_check_unique checks every row in table when doing update??

From: Mats Lofkvist <mal(at)algonet(dot)se>
To: pgsql-bugs(at)postgresql(dot)org
Subject: Re: _bt_check_unique checks every row in table when doing update??
Date: 2002-09-12 15:09:09
Message-ID: y2qbs738ctm.fsf@algonet.se
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tgl(at)sss(dot)pgh(dot)pa(dot)us (Tom Lane) writes:

> > But you really shouldn't need the old tuple to know this since none
> > of the columns present in the unique index are 'set' by the update?
> > I.e. the 'not changing the unique key part' is not data dependent,
> > it is guarantied by the form of the update statement.
>
> (a) that's even further upstream from the index AM, and (b) what about
> BEFORE triggers that change the tuple contents?
>
> regards, tom lane

Ok, I rest my case. I obviously don't know enough of the
postgres internals to suggest a usable solution for this
problem. Thanks for your quick answers.

_
Mats Lofkvist
mal(at)algonet(dot)se

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