From: Andrew Dunstan <andrew.dunstan@2ndquadrant.com>
Subject: Re: [RFC] Removing "magic" oids
To: Andres Freund <andres@anarazel.de>
Cc: pgsql-hackers@postgresql.org
References: <20180930034810.ywp2c7awz7opzcfr@alap3.anarazel.de>
 <20181114080152.xkk6coduvfrh4ntr@alap3.anarazel.de>
 <20181115014807.kqhndjzbvdmkbkhv@alap3.anarazel.de>
 <20181120095227.tgc5edxjqegobtkg@alap3.anarazel.de>
 <20181121000759.dgcbhr2nizkcfjhk@alap3.anarazel.de>
 <91a8a980-41bc-412b-fba2-2ba71a141c2b@2ndQuadrant.com>
 <02C51EE4-D0AE-4855-AF39-7EBC9D0CBB96@anarazel.de>
 <20181122001415.ef5bncxqin2y3esb@alap3.anarazel.de>
 <c422a08f-720d-925c-e9d7-63432e668a38@2ndQuadrant.com>
 <20181122211452.3bffatkaknmrvkdq@alap3.anarazel.de>
Message-ID: <37786ace-8622-e4ba-43b5-50496f88b68d@2ndQuadrant.com>
Date: Thu, 22 Nov 2018 17:12:31 -0500
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101
 Thunderbird/60.3.0
MIME-Version: 1.0
In-Reply-To: <20181122211452.3bffatkaknmrvkdq@alap3.anarazel.de>
Content-Type: text/plain; charset=utf-8; format=flowed
Content-Transfer-Encoding: 7bit
Content-Language: en-MW
Precedence: bulk


On 11/22/18 4:14 PM, Andres Freund wrote:
> Hi,
>
> On 2018-11-21 23:32:07 -0500, Andrew Dunstan wrote:
>> On 11/21/18 7:14 PM, Andres Freund wrote:
>>>    Could you check whether you
>>> still encounter the issue after applying the attached fix?
>>>
>>
>> This has largely fixed the problem, so I think this should be applied.
> Cool, will do so tomorrow or such. Thanks for testing.
>
>
>> With some adjustments to the tests to remove problematic cases (e.g.
>> postgres_fdw's ft_pg_type) the tests pass. The exception is
>> HEAD->HEAD. The change is that the LOs are not dumped in the same
>> order pre and post upgrade. I can change the tests to allow for a
>> greater fuzz factor - generally when the source and target are the
>> same we don't allow any fuzz.  Or if we care we could do a better job
>> of dumping LOs in a consistent order.
> So you'd want to dump large objects in oid order or such? Probably
> comparatively not a huge overhead, but also not nothing? We don't really
> force ordering in other places in pg_dump afaik.
>

Well, all other data is dumped in a consistent order, and the tests rely 
on this. If we don't care about that for LOs I can accommodate it. I 
don't have a terribly strong opinion about the desirability of making 
LOs keep the same behaviour.


cheers


andrew

-- 
Andrew Dunstan                https://www.2ndQuadrant.com
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services