[wp-hackers] Categories empty on all blogs after PHP upgrade

[Hacker Scot]

>
> From: Peter Westwood <peter.westwood at ftwr.co.uk>
> Subject: Re: [wp-hackers] Categories empty on all blogs after PHP
> 	upgrade
>
> On 8 Apr 2009, at 07:46, Hacker Scot wrote:
>
>> OK, here's a weird one. Upgraded PHP 5.2.8 to 5.2.9 on a server
>> today. The server hosts 90 WP sites on 50 or so domains. Immediately
>> afterwards, all categories on all blogs are empty.
>>
>> wp-admin/categories.php lists all categories with the number of
>> posts in each; click on a category and it shows zero posts. Same on
>> the public/front-end. If I then run Repair Tables via phpmyadmin,
>> wp-admin/categories.php shows zero posts in each category, same on
>> front end. In other words, repair tables seems to make things worse.
>>
>> All WP installations are 2.7.1. None of them were upgraded. This was
>> just a PHP upgrade on a cPanel system with MySQL 4.1.22.
>>
>> Findings lots of solutions in the forums for fixing individual
>> blogs, but nothing about server-wide category problems.
>
>
> This sounds like you've lost all the post<>category relationships
> which would be stored in the term_relationships table.
>
> Is this table empty?
>


Just had a look at the term_relationships table for three of the  
affected blogs (owned by different users/accounts on the server) and  
no, those tables are not empty. The term_order column  is all zeroes,   
but the object_id and term_taxonomy_id columns appear to contain  
normal data.

I just can't see how a PHP upgrade could affect specific data in  
specific tables, affecting all users on the server. Is there any  
conceivable way that something related could be in play, such as the  
PHP-MySQL driver being different, or similar? Any kind of PHP  
environment variable that could have an effect like this?

Grasping at straws with a lot of miffed users. All suggestions welcome.

Thanks,
Scot