| From: | Gregory Stark <stark(at)enterprisedb(dot)com> |
|---|---|
| To: | Stéphane A(dot) Schildknecht <stephane(dot)schildknecht(at)postgresqlfr(dot)org> |
| Cc: | Postgres General <pgsql-general(at)postgresql(dot)org> |
| Subject: | Re: Using xmin to identify last modified rows |
| Date: | 2009-02-25 13:21:12 |
| Message-ID: | 871vtmveif.fsf@oxford.xeocode.com |
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| Lists: | pgsql-general |
"Stéphane A. Schildknecht" <stephane(dot)schildknecht(at)postgresqlfr(dot)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.
--
Gregory Stark
EnterpriseDB http://www.enterprisedb.com
Ask me about EnterpriseDB's 24x7 Postgres support!
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