From: | Heikki Linnakangas <heikki(dot)linnakangas(at)enterprisedb(dot)com> |
---|---|
To: | Zdenek Kotala <Zdenek(dot)Kotala(at)Sun(dot)COM> |
Cc: | PostgreSQL-development <pgsql-hackers(at)postgresql(dot)org> |
Subject: | Re: pg_upgrade: convert on read is dead end |
Date: | 2008-10-13 08:58:54 |
Message-ID: | 48F30DCE.9070305@enterprisedb.com |
Views: | Raw Message | Whole Thread | Download mbox | Resend email |
Thread: | |
Lists: | pgsql-hackers |
Zdenek Kotala wrote:
> Heikki Linnakangas napsal(a):
>> Besides, the "read all formats" approach wouldn't really avoid it
>> either. If you passed a toasted datum to a function, when the function
>> needs to detoast it, detoast_datum still wouldn't know whether the
>> datum is in old or new format. You'd still need to detoast all values
>> in the tuple somewhere before they could be passed around.
>
> If you look into pg_upgrade prototype patch I added page version
> information into HeapTupleData structure. It keeps information about
> format. All chunked data are stored on a pages with same page versions.
> I think these two things are enough to have all necessary information.
Functions are passed just a Datum, not HeapTupleData.
--
Heikki Linnakangas
EnterpriseDB http://www.enterprisedb.com
From | Date | Subject | |
---|---|---|---|
Next Message | ITAGAKI Takahiro | 2008-10-13 09:00:44 | Convert check constraints into One-Time_Filter on prepared statements |
Previous Message | Markus Wanner | 2008-10-13 08:53:44 | Re: The Axe list |