wordpress upgrade failed. drops to install screen. database schema not upgraded

[rob]

After I upgraded from 10.04.3 to 12.04, wordpress started redirecting to the install.php install screen.

Digging through the mysql database, I saw nothing wrong as all the settings and posts were there. So I continued on the install screen, and entered the admin user & password. Now in mysql there are duplicate tables with a fresh install.

For example there is both the 'options' table with all the old options and a 'wp_options' table with the fresh install.

So it looks like the upgrade from Lucid to Precise failed to migrate the wordpress database to a new schema.

[rob (4-launchpad-com-spm-egannetworks-com)]

Update. As it seems that my wordpress instance does not have the 'wp_' prefix on most of the database tables, it was 3 new lines in the updated /etc/wordpress/wp-config.php that caused the problem:

if (!isset($table_prefix)) {
    $table_prefix = 'wp_';
}

The fix was to restore the wordpress database from backup and then add one line, setting $table_prefix to '' in my site's /etc/wordpress/config-default.php where the database passwords are.

$table_prefix = '';

And then run the Automatic Updater normally:
http://localhost/wordpress/wp-admin/update-core.php

[Raphaël Hertzog (hertzog)]

On Sat, 28 Apr 2012, rob wrote:
> Public bug reported:
>
> After I upgraded from 10.04.3 to 12.04, wordpress started redirecting to
> the install.php install screen.
>
> Digging through the mysql database, I saw nothing wrong as all the
> settings and posts were there. So I continued on the install screen,
> and entered the admin user & password. Now in mysql there are duplicate
> tables with a fresh install.
>
> For example there is both the 'options' table with all the old options
> and a 'wp_options' table with the fresh install.
>
> So it looks like the upgrade from Lucid to Precise failed to migrate the
> wordpress database to a new schema.

Hi,

This has nothing to do with a new schema but just with the $table_prefix
option. It's set to "wp_" by default in the precise package but AFAIK it
has been that way for a long time.

Are you sure you didn't have a specific configuration where the prefix was
set to empty ?

Can you attach the content of /etc/wordpress/ ?

Thus you can recover your former content by changing the wordpress
configuration in /etc/wordpress/wp-config.php and switching $table_prefix
to ''.

Cheers,
--
Raphaël Hertzog ◈ Debian Developer

Pre-order a copy of the Debian Administrator's Handbook and help
liberate it: http://debian-handbook.info/liberation/

[rob (4-launchpad-com-spm-egannetworks-com)]

Hi thanks for the clarification. I agree the problem was in the prefix, or lack thereof, of my database's wordpress tables.

I originally installed wordpress in Jan 2008 and have propagated the database all the way from 32-bit feisty to 64-bit lucid and, recently, precise. So sometime in the past 4 years the default 'wp_' prefix was set but didn't get applied to my mysql instance.

The fix that worked for me was to include $table_prefix=''; in my /etc/wordpress/config-default:

<?php

define('DB_NAME', 'wordpress');
define('DB_USER', 'wordpress');
define('DB_PASSWORD', '***my*password*here****');
define('DB_HOST', 'localhost');

$table_prefix = '';

?>

Incidentally only some of the wordpress tables have the wp_ prefix on my system.

mysql> use wordpress
Reading table information for completion of table and column names
You can turn off this feature to get a quicker startup with -A

Database changed
mysql> show tables
    -> ;
+----------------------+
| Tables_in_wordpress |
+----------------------+
| commentmeta |
| comments |
| links |
| options |
| postmeta |
| posts |
| term_relationships |
| term_taxonomy |
| terms |
| usermeta |
| users |
| wp_email_list |
| wp_email_list_config |
| wp_email_list_future |
+----------------------+