Re: Questions about update, delete, ctid...

[DANTE Alexandra <Alexandra(dot)Dante(at)bull(dot)net>]

Hello Tom, Martijn and List,

Thank you for yours answers !
This point is now closed for me and I can go further in the mecanisms of 
VACUUM.

Regards,
Alexandra


Tom Lane wrote:

> DANTE Alexandra <Alexandra(dot)Dante(at)bull(dot)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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