How does WP decide how to evaluate database integrity

Question

I've upgraded a handful of WPMU sites from 2.9 to WP3. I've never had problems with that process .. until today, when all of a sudden, one install tells me that the DB is missing some tables. The tables WordPress can't find are not actually supposed to be there in a multisite.

The tables I have are:

wp_1_commentmeta
wp_1_comments
wp_1_links
wp_1_options
wp_1_postmeta
wp_1_posts
wp_1_terms
wp_1_term_relationships
wp_1_term_taxonomy
wp_blogs
wp_blog_versions
wp_registration_log
wp_signups
wp_site
wp_sitecategories
wp_sitemeta
wp_usermeta
wp_users

And that's excactly the tables you get on a vanilla install of WordPress-MU 2.9.2 (not WordPress 2.9.2)

But on this install, after I opgrade the file to WordPress 3.x, WordPress tells me, that the database is missing tables like

wp_posts
wp_comments
etc..

If WordPress was running as a single site, those tables would indeed be missing here, but when updating from WordPress-MU 2.9 they wont be there, and thats normally not causing a problem at this stage.

So my question is, Does anybody know, what it is that determines, wheter WordPress will evaulate the DB integrity according to sinlge site vs. multisite rules?

I'm just guessing that the problem here is, that WordPress is for some reason evaluating the DB as if it was a regular single site install.

Answer 1

I've finally found the answer. Yes WP was 'triggered' to think it was evaluating a WordPress and not a WordPress-MU table structure.

This was caused by the following lines:

define('WP_ALLOW_MULTISITE', true);
define( 'MULTISITE', true );

in the wp-config.php that should NOT be there in a WordPress-MU 2.9.2 installation (but that some former developer had tossed in there anyway)

Once I removed them, I could proceed to the /wp-admin without problems and update the site network.

Answer 2

WPMU 2.9 was the last standalone install of WPMU after that it was added to the standard WP 3.0+ core. See if this helps: http://developersmind.com/2010/06/17/upgrading-wordpress-mu-2-9-2-to-wordpress-3-0/

Answer 3

I had a similar issue. It turned out that my tables didn't have the proper domain set.

check if the domain values are correct in wp_blogs, wp_options, wp_site and wp_sitemeta.

i.e. wp_blogs.domain should equal the right domain for your site.

HTH