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

From Tom Lane
Subject Re: Questions about update, delete, ctid...
Date
Msg-id 13663.1154350119@sss.pgh.pa.us
Whole thread Raw
In response to Re: Questions about update, delete, ctid...  (DANTE Alexandra <Alexandra.Dante@bull.net>)
Responses Re: Questions about update, delete, ctid...
List pgsql-general
DANTE Alexandra <Alexandra.Dante@bull.net> writes:
>     - during a SELECT query on a tuple just updated and commited, does
> the executor first detect the old tuple and then via the c_tid link go
> to the new version of the tuple ? or go directly to the new version ?

Neither.  SELECT doesn't care about update relationships, it just
returns whatever row version is current according to its snapshot.
It's only UPDATE/DELETE that are constrained to act on the most
current version of each row.

            regards, tom lane

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