On Mon, Feb 9, 2015 at 1:58 PM, bkrug <bkrug@xxxxxxxxxxx> wrote:
Couldn't postgres reserve a special XID that is never available for normal
transactions but that indicates that any transaction can see it because it
is so old? Then instead of constantly having to freeze old XIDs each time
the XID is going to wrap, vacuum can just set it to the special XID and
never touch it again unless something really changes.
It changed in recent versions (9.3 or 9.4, I don't recall exactly which) and moved to tuple header, but what you described is exactly what was done, the xid was 2.
Anyway, an already frozen tuple won't be "re-frozen" again.
Regards,
--
Matheus de Oliveira
Analista de Banco de Dados
Dextra Sistemas - MPS.Br nível F!
www.dextra.com.br/postgres
Analista de Banco de Dados
Dextra Sistemas - MPS.Br nível F!
www.dextra.com.br/postgres
