I found the problem this issue is coming from com_easyblog component, please you contact easyblog developer or remove this block code

administrator/components/com_easyblog/includes/jomsocial/jomsocial.php:				$query	= 'DELETE FROM ' . $db->quoteName('#__community_activities' ) . ' '

We only installed EasyBlog recently. So if this is causing it, there is something else that does it too..

:(

Please investigate further.

please try to delete the block query code on this file administrator/components/com_easyblog/includes/jomsocial/jomsocial.php, and let we see how it goes

No, this can not be it. The SQL goes like this:

if ($exists) {

				$query	= 'DELETE FROM ' . $db->quoteName('#__community_activities' ) . ' '
						. 'WHERE ' . $db->quoteName('app') . '=' . $db->Quote('com_easyblog' ) . ' '
						. 'AND ' . $db->quoteName('cid') . '=' . $db->Quote($commentId) . ' '
						. 'AND ' . $db->quoteName('comment_type') . '=' . $db->Quote('com_easyblog.comments');

				$db->setQuery($query);
				$db->Query();
			}

Ehm, open this file components/com_community/events/wall.trigger.php and delete this code :

$sql = 'DELETE FROM ' . $db->quoteName('#__community_activities')
			.' WHERE ' . $db->quoteName('cid') .' = '. $db->Quote($id)
			.' AND ' . $db->quoteName('app') .' = ' . $db->Quote('groups.wall');
		$db->setQuery($sql);
		$db->execute();

OK, I've made this code block inactive (by commenting out the last two lines of that block).

So, lets we wait how it goes then

We will have to wait, but this is probably not the reason.

The SQL this one generates is something like:

DELETE FROM 'bu_community_activities'
WHERE cid = '($id)' AND app = 'groups.wall'

I do not see that this can generate a SQL that deletes all the groups.wall posts, since it will have to have a CID

SELECT * FROM `bu_community_activities` WHERE cid = '__' AND app = 'groups.wall'
where __ is * or ? etc will not generate any results.

So I guess we will just have to wait until it happens again.. :(