Re: Using xmin to identify last modified rows

"Stéphane A. Schildknecht" <stephane.schildknecht@postgresqlfr.org> writes:

> But, trying the same query on a non slonified DB, I got an error, as there is
> no ordering operator for xid.
>
> I think that in the slon case, the query uses the implicit cast xid->xxid, and
> then the operator to sort xxid.

You could order by age(xmin) instead

> What would be the best way to get last modified rows?

I'm not sure using xmin is such a great idea really. It's handy for ad-hoc
queries but there are all kinds of cases where it might not give you the
results you expect.

You probably want to put a timestamp column on your tables and manage the date
you put in their according to a policy you control.


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  Gregory Stark
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