Re: Switched to PostgreSQL

Daniel Vrátil <[email protected]> Wed, 17 Apr 2019 15:37:38 +0200
Newsgroups	gmane.comp.kde.users.pim
Message-ID	<3400458.MHq7AAxBmi@brokkr>
On Monday, 15 April 2019 01:24:54 CEST Paul Vixie wrote:
> David Goodenough wrote on 2019-04-11 08:35:
> >> On Thursday, 11 April 2019 13:07:10 BST Vojtěch Zeisek wrote:
> >> Regarding PostgreSQL, I always had feeling that upgrade of
> >> PostgreSQL is not so straightforward as upgrade of MySQL.
> >> PostgreSQL DB must be exported, than cluster upgraded, settings
> >> restored and old DB imported. How do users of PostgreSQL and
> >> Akonadi handle this when upgrading their distribution?
> > 
> > I have been using Postgresql ever since Akonadi started, and the upgrade
> > just means that you have to remember to stop akonadi before the upgrade,
> > then do the upgrade, and then restart akonadi. My system takes backups
> > every day so I never did an extra one, and I have never needed to use
> > the backup. I have also never needed to to anything with any settings.
> > This is on Debian.
> 
> i've had an experience of a third kind (counting #1 and #2 above).
> 
> when suse-tumbleweed gave me a new major release of postgres recently,
> the server that akonadi starts under my UID refused to launch. while
> there is an in-place-upgrade method now, so as to avoid export & import,
> akonadi's database driver is unaware of this. i briefly considered doing
> this operation by hand, until i realized, i've been simply removing the
> database and letting akonadi rebuild it, every week or less, so i just
> did that. yes, it loses track of all my Sent, Drafts, Templates, and
> Favorites. and if i had any filters it would lose those too. so, this
> technique isn't for everybody.
> 
> for minor releases like 10.x to 10.(x+1), the server restarts fine. it's
> only for major releases like 9.x to 10.x, that special work is required.
> i expect that due to the performance and stability problems in mariadb,
> postgresql will shortly become the akonadi default, at which time it may
> acquire the skill of running the postgresql in-place-upgrade procedure,
> and may start to use postgresql's built-in full text index features, vs.
> maintaining a separate database table for the index, as it does today.

It won't become the default until we can automate the migration after a major 
PostgreSQL upgrade - which is not easy, since you have to make sure you have 
both the previous and the new version of PostgreSQL installed in the system, 
the location of course differs among distros - so for now PostgreSQL is only 
for advanced users who know how to deal with the migration manually.

We could detect the need for migration fairly easy in Akonadi, showing a clear 
and nice error dialog in this case to explain what's going on and what the 
user has to do could be a nice improvement for this.

- Dan



-- 
Daniel Vrátil
www.dvratil.cz | [email protected]
IRC: dvratil on Freenode (#kde, #kontact, #akonadi, #fedora-kde)

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