Re: Questions about update, delete, ctid... - Mailing list pgsql-general

From Tom Lane
Subject Re: Questions about update, delete, ctid...
Date
Msg-id 13104.1154348717@sss.pgh.pa.us
Whole thread Raw
In response to Re: Questions about update, delete, ctid...  (Martijn van Oosterhout <kleptog@svana.org>)
List pgsql-general
Martijn van Oosterhout <kleptog@svana.org> writes:
> On Mon, Jul 31, 2006 at 11:04:58AM +0200, DANTE Alexandra wrote:
>> I've just seen that I've done a mistake in my example. My question was :
>> is it correct to think that the ctid of the old version of the tuple is
>> a link to newer version ?

> Well, in your case where there are no other transactions running, yes.
> In the general case there may have been other updates so all you know
> is that the new tuple is a descendant of the old one. The chain of
> t_ctid links can be arbitrarily long.

It's probably worth pointing out here that the "ctid" column exposed
at the SQL level is not the same as t_ctid --- it's what the C code calls
t_self.

            regards, tom lane

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