Re: Dev chat reminder, issue

0fbcd3ab-0ace-4e23-9100-53e04aaea892
Reply-To:
In-Reply-To: <[email protected]>
Errors-To: [email protected]
X-Operating-System: GNU/Linux x86_64 3.12.7-2-ARCH
X-Editor: VIM - Vi IMproved 7.4 (2013 Aug 10, compiled Mar 24 2014 19:35:25)
X-Accept-Primary-Language: en
X-Accept-Secondary-Language: de
X-Accept-Tertiary-Language: eo
X-Google-Loop: groups

On Tue, Jun 03, 2014 at 02:09:40PM +0200, Wieland Hoffmann wrote:
> Hallo Robert Kaye:
> >
> > On Jun 2, 2014, at 4:44 PM, Wieland Hoffmann <[email protected]> wrote:
> >
> > > Last week I did a bit of code cleanup and then began working on
> > > generating triggers to push information about changes in the DB to
> > > RabbitMQ.
> >
> > Cool -- could we make it so that a remote DB can consume data from
> > this queue to create a very-low-latency replicated instance of MB?
>
> I don't think so, unfortunately. The way it works (or is supposed to
> work when I'm finished :P) is that once a change happens the messages
> sent via RabbitMQ include only the IDs of entitities that need to be
> reindexed (say you change the status of a release, you need to reindex
> at least all related recordings and the release group).
>
> It could probably be modified to just dump the changes, but that sounds
> a lot like PGs streaming replication feature [0].
>
> [0] https://wiki.postgresql.org/wiki/Streaming_Replication

In general streaming replication is the better option, and newer
postgres versions are adding better and better tools for this. It's
worth noting that we'd only need to add a trigger to two tables,
dbmirror_pending and dbmirror_pendingdata, that include the full data,
which may be better. Our current postgres version doesn't have
row_to_json which makes that much nicer/easier (just send out a json
blob!) but it may be an option in the future.

>
> --
> Wieland
>
> _______________________________________________
> MusicBrainz-devel mailing list
> [email protected]
> http://lists.musicbrainz.org/mailman/listinfo/musicbrainz-devel

_______________________________________________
MusicBrainz-devel mailing list
[email protected]
http://lists.musicbrainz.org/mailman/listinfo/musicbrainz-devel

-----BEGIN PGP SIGNATURE-----
Version: GnuPG v2.0.22 (GNU/Linux)

iEYEARECAAYFAlON73IACgkQq+0avXExp28FmQCeJITzNG+OMHnl2g1aXUZr3ob6
GlQAoKoKT5zYLTT38dG1FPJveVEnWjYW
=fzsi
-----END PGP SIGNATURE-----