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 <[EMAIL PROTECTED]> 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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