Subject: Re: pg_dump vs. TRANSFORMs
To: Tom Lane <tgl@sss.pgh.pa.us>
References: <20160504183952.GE10850@tamriel.snowman.net>
 <0a288671-29ec-ecdd-d8ae-e0f5c73dcc8d@2ndquadrant.com>
 <15548.1462418615@sss.pgh.pa.us>
Cc: Stephen Frost <sfrost@snowman.net>, pgsql-hackers@postgresql.org
From: Peter Eisentraut <peter.eisentraut@2ndquadrant.com>
Organization: 2ndQuadrant
Message-ID: <376f5fb1-85cb-6b4c-9927-645b5e209456@2ndquadrant.com>
Date: Thu, 5 May 2016 08:28:27 -0400
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On 5/4/16 11:23 PM, Tom Lane wrote:
> Actually, I believe it will be dumped.  selectDumpableCast believes it
> should dump casts with OID >= FirstNormalObjectId.  That's a kluge no
> doubt, but reasonably effective; looks like we've been doing that since
> 9.0.
>
> pg_dump appears not to have a special-case selectDumpableTransform
> routine.  Instead it falls back on the generic selectDumpableObject
> for transforms.  That's a bad idea because the only useful bit of
> knowledge selectDumpableObject has is to look at the containing
> namespace ... and transforms don't have one, just as casts don't.
>
> My recommendation is to clone that cast logic for transforms.

Hmm.  The way I understand it is that Stephen wants to make dumping that 
test case work.  But note that that test case is bogus; it wouldn't 
actually do anything useful in practice.  There aren't any functions in 
the system catalog that could be used for actual transforms.  So making 
these changes in pg_dump isn't really of much practical value.  Perhaps 
it would be easier to change the test case or adjust the testing procedure?

-- 
Peter Eisentraut              http://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services


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