[openstack-dev] [Fuel] PostgreSQL 9.3 and JSON operations

Mike Scherbakov mscherbakov at mirantis.com
Wed Dec 16 07:23:52 UTC 2015


Wow such a hot topic...
I'm also the one who voted for 9.2. But I also voted like Alexey S., "I'm
conservative..." - I am actually mostly conservative, and would question
every new cool tool/feature of library unless there is a very good proof on
using it. You can't build a product which will have 90% of cool pars
designed over the last year, that's the reason I'm conservative here too.

Then I learned that we actually had 9.3 before, and now asking if we want
to downgrade to 9.2. My answer is _NO_ under any circumstances to such
changes after Feature Freeze. We've been running lots of installs on 9.3,
and it is too late to change package version after FF from risk management
perspectives. Whether it is downgrade or upgrade.

We could consider downgrading in Fuel 9.0, but I'd very carefully consider
that. As Vladimir Kuklin said, there are may be other users who already
rely on 9.3 for some of their enhancements.

Good question from Julien - even though we are unlikely to replace Postgres
by something else in Fuel, we should still try to use as less
postgres-specific features as possible. Reason is that we might want to
make HA for DB layer some day. In case of MySQL, we can take our existing
ocf scripts for Galera. In case of Postgres, we would have to learn how to
make it HA.


On Tue, Dec 15, 2015 at 2:48 PM Alexey Shtokolov <ashtokolov at mirantis.com>
wrote:

> Dmitry,
>
> Thank you for this document!
> Please move it on https://etherpad.openstack.org to make it accessible
>
> Best regards,
> Alexey Shtokolov
>
> 2015-12-16 1:38 GMT+03:00 Dmitry Teselkin <dteselkin at mirantis.com>:
>
>> Hello,
>>
>> I made an attempt to gather all valuable points 'for' and 'against'
>> 9.2.x in one document [1]. Please take a look on it, I also put some
>> comments there to keep everything in one place. I believe this can help
>> us to make deliberated decision.
>>
>> Please add more pros / cons there as I don't pretend to make a
>> full picture at the first attempt.
>>
>> Just in case, I'd prefer to 'downgrade' to 9.2 :)
>>
>> [1] https://etherpad.mirantis.net/p/7ZUruwlwJM
>>
>> On Tue, 15 Dec 2015 20:47:41 +0200
>> Igor Kalnitsky <ikalnitsky at mirantis.com> wrote:
>>
>> > FYI: so far (according to poll [1]) we have
>> >
>> > * 11 votes for keeping 9.2
>> > * 4 votes for restoring 9.3
>> >
>> > [1]
>> >
>> https://docs.google.com/spreadsheets/d/1RNcEVFsg7GdHIXlJl-6LCELhlwQ_zmTbd40Bk_jH1m4/edit?usp=sharing
>> >
>> > On Tue, Dec 15, 2015 at 8:34 PM, Vladimir Kuklin
>> > <vkuklin at mirantis.com> wrote:
>> > > Folks
>> > >
>> > > Let me add my 2c here.
>> > >
>> > > I am for using Postgres 9.3. Here is an additional argument to the
>> > > ones provided by Artem, Aleksandra and others.
>> > >
>> > > Fuel is being sometimes highly customized by our users for their
>> > > specific needs. It has been Postgres 9.3 for a while and they might
>> > > have as well gotten used to it and assumed by default that this
>> > > would not change. So some of their respective features they are
>> > > developing for their own sake may depend on Postgres 9.3 and we
>> > > will never be able to tell the fraction of such use cases.
>> > > Moreover, downgrading DBMS version of Fuel should be inevitably
>> > > considered as a 'deprecation' of some features our software suite
>> > > is providing to our users. This actually means that we MUST provide
>> > > our users with a warning and deprecation period to allow them to
>> > > adjust to these changes. Obviously, accidental change of Postgres
>> > > version does not follow such a policy in any way. So I see no other
>> > > ways except for getting back to Postgres 9.3.
>> > >
>> > >
>> > > On Tue, Dec 15, 2015 at 7:39 PM, Igor Kalnitsky
>> > > <ikalnitsky at mirantis.com> wrote:
>> > >>
>> > >> Hey Mike,
>> > >>
>> > >> Thanks for your input.
>> > >>
>> > >> > actually not.  if you replace your ARRAY columns with JSON
>> > >> > entirely,
>> > >>
>> > >> It still needs to fix the code, i.e. change ARRAY-specific queries
>> > >> with JSON ones around the code. ;)
>> > >>
>> > >> > there's already a mostly finished PR for SQLAlchemy support in
>> > >> > the queue.
>> > >>
>> > >> Does it mean SQLAlchemy will have one unified interface to make
>> > >> JSON queries? So we can use different backends if necessary?
>> > >>
>> > >> Thanks,
>> > >> - Igor
>> > >>
>> > >> On Tue, Dec 15, 2015 at 5:06 PM, Mike Bayer <mbayer at redhat.com>
>> > >> wrote:
>> > >> >
>> > >> >
>> > >> > On 12/15/2015 07:20 AM, Igor Kalnitsky wrote:
>> > >> >> Hey Julien,
>> > >> >>
>> > >> >>>
>> > >> >>>
>> https://blueprints.launchpad.net/fuel/+spec/openstack-ha-fuel-postgresql
>> > >> >>
>> > >> >> I believe this blueprint is about DB for OpenStack cloud (we use
>> > >> >> Galera now), while here we're talking about DB backend for Fuel
>> > >> >> itself. Fuel has a separate node (so called Fuel Master) and we
>> > >> >> use PostgreSQL now.
>> > >> >>
>> > >> >>> does that mean Fuel is only going to be able to run with
>> > >> >>> PostgreSQL?
>> > >> >>
>> > >> >> Unfortunately we already tied up to PostgreSQL. For instance,
>> > >> >> we use PostgreSQL's ARRAY column type. Introducing JSON column
>> > >> >> is one more way to tighten knots harder.
>> > >> >
>> > >> > actually not.  if you replace your ARRAY columns with JSON
>> > >> > entirely, MySQL has JSON as well now:
>> > >> > https://dev.mysql.com/doc/refman/5.7/en/json.html
>> > >> >
>> > >> > there's already a mostly finished PR for SQLAlchemy support in
>> > >> > the queue.
>> > >> >
>> > >> >
>> > >> >
>> > >> >>
>> > >> >> - Igor
>> > >> >>
>> > >> >> On Tue, Dec 15, 2015 at 12:28 PM, Julien Danjou
>> > >> >> <julien at danjou.info> wrote:
>> > >> >>> On Mon, Dec 14 2015, Igor Kalnitsky wrote:
>> > >> >>>
>> > >> >>>> The things I want to notice are:
>> > >> >>>>
>> > >> >>>> * Currently we aren't tied up to PostgreSQL 9.3.
>> > >> >>>> * There's a patch [2] that ties Fuel up to PostgreSQL 9.3+ by
>> > >> >>>> using a set of JSON operations.
>> > >> >>>
>> > >> >>> I'm curious and have just a small side question: does that
>> > >> >>> mean Fuel is
>> > >> >>> only going to be able to run with PostgreSQL?
>> > >> >>>
>> > >> >>> I also see
>> > >> >>>
>> > >> >>>
>> https://blueprints.launchpad.net/fuel/+spec/openstack-ha-fuel-postgresql,
>> > >> >>> maybe it's related?
>> > >> >>>
>> > >> >>> Thanks!
>> > >> >>>
>> > >> >>> --
>> > >> >>> Julien Danjou
>> > >> >>> // Free Software hacker
>> > >> >>> // https://julien.danjou.info
>> > >> >>
>> > >> >>
>> > >> >>
>> __________________________________________________________________________
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>> > >> >>
>> > >> >
>> > >> >
>> > >> >
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>> > >>
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>> > >
>> > >
>> > >
>> > > --
>> > > Yours Faithfully,
>> > > Vladimir Kuklin,
>> > > Fuel Library Tech Lead,
>> > > Mirantis, Inc.
>> > > +7 (495) 640-49-04
>> > > +7 (926) 702-39-68
>> > > Skype kuklinvv
>> > > 35bk3, Vorontsovskaya Str.
>> > > Moscow, Russia,
>> > > www.mirantis.com
>> > > www.mirantis.ru
>> > > vkuklin at mirantis.com
>> > >
>> > >
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>> >
>> >
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>>
>>
>> --
>> Thanks,
>> Dmitry Teselkin
>>
>>
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-- 
Mike Scherbakov
#mihgen
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