Re: Database file copy

On Fri, Jan 14, 2011 at 9:13 AM, Bruce Momjian <bruce(at)momjian(dot)us> wrote:
> Alvaro Herrera wrote:
>> Excerpts from Bruce Momjian's message of jue ene 13 00:05:53 -0300 2011:
>> > Srini Raghavan wrote:
>> > > Thank you very much for reviewing, appreciate the feedback.? As pointed out by
>> > > you, it is always best to test it out with the latest version, so, I tested the
>> > > same approach with postgres 9.0.2 on windows just now, and it works!
>> > >
>> > >
>> > > I forgot to mention earlier that in addition to setting vacuum_freeze_table_age
>> > > to 0, vacuum_freeze_min_age must also be set to 0 to reset xmin with the
>> > > FrozenXid.
>> >
>> > I wonder if you should be using VACUUM FREEZE instead of having to set
>> > variables.
>>
>> The documentation says you shouldn't:
>>
>> FREEZE
>> Selects aggressive "freezing" of tuples. Specifying FREEZE is equivalent to
>> performing VACUUM with the vacuum_freeze_min_age parameter set to zero. The
>> FREEZE option is deprecated and will be removed in a future release; set the
>> parameter instead.
>>       http://www.postgresql.org/docs/9.0/static/sql-vacuum.html
>
> I didn't know that.  I added the -z(freeze) option to vacuumdb in 8.4
> for use by pg_upgrade.
>
> I think the original idea was that people should never need to freeze
> anything, but it turns out pg_upgrade and this user need it so maybe
> depricating is not a good idea.  I guess pg_upgrade could call vacuumdb
> with a PGOPTIONS flag to force a vacuum_freeze_min_age value.

I'd rather remove the deprecating warning.

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company