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Re: Largeobject Access Controls and pg_migrator

From: Bruce Momjian <bruce(at)momjian(dot)us>
To: KaiGai Kohei <kaigai(at)kaigai(dot)gr(dot)jp>
Cc: KaiGai Kohei <kaigai(at)ak(dot)jp(dot)nec(dot)com>, Takahiro Itagaki <itagaki(dot)takahiro(at)oss(dot)ntt(dot)co(dot)jp>, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>, Jaime Casanova <jcasanov(at)systemguards(dot)com(dot)ec>, Greg Smith <greg(at)2ndquadrant(dot)com>, pgsql-hackers(at)postgresql(dot)org
Subject: Re: Largeobject Access Controls and pg_migrator
Date: 2009-12-13 02:15:42
Message-ID: 200912130215.nBD2Fgc26991@momjian.us (view raw or flat)
Thread:
Lists: pgsql-hackers
KaiGai Kohei wrote:
> lo_import() has an another prototype which takes second argument to
> specify LOID. Isn't it available to restore a large object with
> correct LOID? For example, lo_import('/etc/profile', 1234)

I can't use that because the migration has already brought over the
pg_largeobject file which has the data.

> Or, if you intend to restore metadata in the second lo_import(),
> ALTER LAEGE OBJECT and GRANT LARGE OBJECT enable to set up metadata
> of a certain large object.

Yes, that will work cleanly.  The file might be large because I need a
GRANT for every large object, but I suppose that is OK.

> > You might remember that INSERT cannot set the oid of a row, so I don't
> > see how pg_migrator can migrate this?  Is there a reason we used 'oid'
> > in pg_largeobject_metadata but 'lobj' in pg_largeobject?  Why did't we
> > add the lomowner and lomacl columns to pg_largeobject?
> 
> A large object consists of multiple tuples within pg_largeobject.
> If we added lomowner and lomacl into pg_largeobject, we have to manage
> all the pages in a large object to keep consistent state.

Ah, good point.

-- 
  Bruce Momjian  <bruce(at)momjian(dot)us>        http://momjian.us
  EnterpriseDB                             http://enterprisedb.com

  + If your life is a hard drive, Christ can be your backup. +

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Next:From: Bruce MomjianDate: 2009-12-13 02:31:01
Subject: Re: Largeobject Access Controls and pg_migrator
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Subject: Re: Largeobject Access Controls and pg_migrator

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