[HyperDB] Partitioning wpmu data

[Callum Macdonald]

Felix, you're absolutely right, you do need to include db-settings.php
in wp-config.php.

As I understand it, you don't need to configure the default db settings.
HyperDB will automatically pick up the settings in wp-config.php and use
those. So if you just want to test, install db.php in wp-content/ and
don't include db-settings.php.

Then you can try adding db-settings.php and see if it works as you
expect.

Cheers - Callum.

On Mon, 2009-04-27 at 09:31 -0700, Felix Gushansky wrote:
> Hm, but the add_db_server (a function in db.php) is being called from
> db-settings.php, which I think *won't* get executed unless I require it in
> the wp-config, no? That add_db_server call carries the info about my (in
> this case default) database.
> 
> Thanks,
> -- Felix
> 
> > From: Callum Macdonald <lists.automattic.com at callum-macdonald.com>
> > Reply-To: <hyperdb at lists.automattic.com>
> > Date: Sun, 26 Apr 2009 19:18:14 -0700
> > To: <hyperdb at lists.automattic.com>
> > Subject: Re: [HyperDB] Partitioning wpmu data
> > 
> > I don't think you need to do add any require() calls. WordPress will
> > automatically pick up a file called db.php in wp-content.
> > 
> > As far as I'm aware, you can drop in the HyperDB class and it will
> > automatically fall back on the default db details, in effect changing
> > almost nothing.
> > 
> > Cheers - Callum.
> > 
> > On Fri, 2009-04-24 at 11:01 -0700, Felix Gushansky wrote:
> >> Hi, folks. Before getting into the depths of db partitioning I am having
> >> trouble making the thing to work with just my default db. Seemingly the
> >> simplest thing in the world: added define and require lines to wp-config (at
> >> the top), dropped in db-settings.php, uncommented the default add_db_server
> >> ('global') line in it, made sure all variables are defined and good, dropped
> >> in db.php in the wp-content dir -- just like prescribed. Croaking in the
> >> wpmu-settings.php - I think 'SELECT * FROM sites' does not give back the
> >> data resulting in 'count( $sites )' to be equal to 1 -- which is what seems
> >> to be expected. As soon as I disable the plugin (commenting out the define
> >> and the require lines in the wp-config.php) everything is back to normal.
> >> 
> >> Any ideas what could be wrong?
> >> 
> >> Thanks,
> >> -- Felix
> >> 
> >> 
> >>> From: Callum Macdonald <lists.automattic.com at callum-macdonald.com>
> >>> Reply-To: <hyperdb at lists.automattic.com>
> >>> Date: Thu, 23 Apr 2009 11:57:29 -0700
> >>> To: <hyperdb at lists.automattic.com>
> >>> Subject: Re: [HyperDB] Partitioning wpmu data
> >>> 
> >>> As Andy said, HyperDB is about on the money for what you want.
> >>> 
> >>> The biggest challenge you'll face will be moving the data. You have 11k
> >>> tables in one database right now, you need to move those to new
> >>> databases. The MultiDB class uses the same method as HyperDB did
> >>> originally, 4096 databases, first 3 digits of the md5 of the blog_id
> >>> (the NNN number).
> >>> 
> >>> I think your best bet will be to use HyperDB and create your own system
> >>> for managing which blog is in which database (maybe a lookup table like
> >>> Andy mentioned). That way you'll be able to migrate the data over time.
> >>> 
> >>> Other options that occur to me:
> >>> 
> >>> Migrate all the data at once. Take the whole system down for a few hours
> >>> and move all the tables as you need to. Pray nothing goes wrong. :-)
> >>> 
> >>> You could add some logic that checks if the table is found in the new
> >>> target database, and if not, fall back on the global database. That
> >>> would allow you to move blogs one at a time, without changing any code.
> >>> If the blog tables are in the new database, the queries go there, if
> >>> not, the queries go to the master table.
> >>> 
> >>> If you're looking for help, you could speak to the guys at Incsub. I'm a
> >>> (present and about to be) retired staffer there, so I'm biased. :-)
> >>> 
> >>> Best of luck with the project.
> >>> 
> >>> Cheers - Callum.
> >>> 
> >>> On Thu, 2009-04-23 at 10:32 -0700, Felix Gushansky wrote:
> >>>> Hello, folks. We have just inherited the site that uses wordpress MU (ver
> >>>> 2.5.1) with MySQL 5 on the back. Soon we have learned that the blog db is
> >>>> huge. Not size wise necessarily (it is slightly over a gig), but table
> >>>> wise.
> >>>> That db contains over 11,000 tables with the total of over 40,000 files in
> >>>> the same directory. That hugely affects performance AND maintenance ­ to
> >>>> the
> >>>> point in fact that we can not backup the db using mysqldump. We had to
> >>>> write
> >>>> a script dumping a table at a time.
> >>>> 
> >>>> So, we need to scale somehow. That¹s why he have looked at HyperDB, which
> >>>> seems to have been built just for that. However, the problem we are seeing
> >>>> is that in our case the tables in the blog db are created and named
> >>>> dynamically. For each new user wpmu creates multiple tables (8?) in the
> >>>> database and names them like wp_<nnnn>_comments, wp_<nnnn>_links,
> >>>> wp_<nnnn>_options, wp_<nnnn>_postmeta, wp_<nnnn>_posts, etc, where <nnnn>
> >>>> is
> >>>> a four digit integer. Can we take advantage of HyperDB in this case? And if
> >>>> not what are our options?
> >>>> 
> >>>> Thanks very much folks. Your help is very much appreciated.
> >>>> 
> >>>> -- Felix
> >>>> _______________________________________________
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> >>>> HyperDB at lists.automattic.com
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