No products showing in Magento back end - front end is OK?

We have an established Magento store running Magento 1.4.2.0 and recently something happened to make all of the products in the back end disappear. The products still show properly on the front end and as far as I can tell the store is still working correctly.

Categories show in the admin, and you can see that the categories have products assigned to them. Here is what I have tried so far:

1. Checked the server free space and load - both are quite acceptable (66% disk space used, load of < 0.1 )
2. Cleared the cache using the Magento admin.
3. Physically removed the cache folder and recreated it with the same permissions.
4. Reindexed all tabled using the Magento admin.
5. Restarted Apache (v2.x)
6. Restarted MySQL (v5.x)
7. Checked the Apache error logs and Magento report directory for issues (both are writable and have some content in it but not of consequence)
8. Checked the HTTP response of the request - there are no failed AJAX calls or non-HTTP 200 statuses (apart from cached responses).
9. Cleared the browser cache and tried both Chrome and Firefox.
10. Taken a copy of the DB and all files and I can reproduce this issue. It appears to be database related as when I loaded up a copy of the production database the products disappeared.
11. Checked the permissions/ownership on the application directory with the following:
    1. chown -R www-data:www-data .
    2. find . -type f -exec chmod 640 {} \;
    3. find . -type d -exec chmod 750 {} \;
开发者_开发技巧

Changing the store view does not change what is visible.

Given that I don't know what the scope of the problem is I'm a little hesitant to go so far as restarting the server itself (although will try this tonight during a quiet time) to resolve this problem without getting some input from others. We have full root access to the box so can poke and play.

Here's a screenshot of products in Magento admin: http://i.stack.imgur.com/wTkwr.png

Note in particular that there are no filter options - these normally appear when you look at a list of products, even if there are none to display.

All ideas welcomed.

Cheers,

- Bob -

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Looks like all products are in the database, but you don't see a grid in the admin because of error somewhere in the code. Switch on the developer mode (add in the .htaccess: SetEnv MAGE_IS_DEVELOPER_MODE 1), it will help you to see what happened. Check Magento and server log files - maybe some errors you will find here. Also increase PHP Memory limit. If you use a CVS, try to rollback. The error you get is 90% caused by code changes.