On Wed, Jul 27, 2016 at 3:34 AM, Achilleas Mantzios <
ach...@matrix.gatewaynet.com> wrote:

> On 27/07/2016 10:15, Condor wrote:
>
>> On 26-07-2016 21:04, Dorian Hoxha wrote:
>>
>>> Many comments: https://news.ycombinator.com/item?id=12166585
>>>
>>> https://www.reddit.com/r/programming/comments/4uph84/why_uber_engineering_switched_from_postgres_to/
>>>
>>> On Tue, Jul 26, 2016 at 7:39 PM, Guyren Howe <guy...@gmail.com> wrote:
>>>
>>> Honestly, I've never heard of anyone doing that. But it sounds like
>>>> they had good reasons.
>>>>
>>>> https://eng.uber.com/mysql-migration/
>>>>
>>>> Thoughts?
>>>>
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>>>
>>
>> They are right for upgrades.
>> It's a hard to shutdown 1 TB database and wait couple of days pg_upgrade
>> to finish upgrade and meanwhile database is offline.
>> In some distros after upgrade of PG version you don't have old binary and
>> library, need to do full dump and restore that take time and disk space.
>>
>
> Our last 1TB upgrade from 9.0 -> 9.3 went like a charm in something like
> seconds. (with the -k option)
> However, be warned that the planing and testing took one full week.
>

That being said, it doesn't really provide a back-out plan.  The beauty of
replication is that you can halt the upgrade at any point if need be and
cut your (hopefully small) losses. If you use -k, you are all in.  Sure,
you could setup a new standby, stop traffic, upgrade whichever node you'd
like (using -k) and still have the other ready in the event of total
catastrophe.  More often than not, I see DBAs and sysads lead the
conversation with "well, postgres can't replicate from one version to
another, so instead.... " followed by a fast-glazing of management's eyes
and a desire to buy a 'commercial database'.

All in all, Evan's blog seemed to start out decently technical, it quickly
took a turn with half-truths, outdated information and, in some cases,
downright fud:

 "The bug we ran into only affected certain releases of Postgres 9.2 and
has been fixed for a long time now. However, we still find it worrisome
that this class of bug can happen at all. A new version of Postgres could
be released at any time that has a bug of this nature, and because of the
way replication works, this issue has the potential to spread into all of
the databases in a replication hierarchy."


ISTM that they needed a tire swing
<http://i0.wp.com/blogs.perficient.com/perficientdigital/files/2011/07/treecomicbig.jpg>
and were using a dump truck.  Hopefully they vectored somewhere in the
middle and got themselves a nice sandbox.

--Scott


>
>
>>
>> Regards,
>> Hristo S.
>>
>>
>>
>>
>>
>>
>
> --
> Achilleas Mantzios
> IT DEV Lead
> IT DEPT
> Dynacom Tankers Mgmt
>
>
>
>
> --
> Sent via pgsql-general mailing list (pgsql-general@postgresql.org)
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>



-- 
--
Scott Mead
Sr. Architect
*OpenSCG <http://openscg.com>*
http://openscg.com

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