Well, I just simply commented the code under database.php that was creating this problem at line 366. Now, it works like a charm.

/*if (mysql_errno($dblink)) {
            throw new DatabaseException(mysql_error($dblink) . "\n\n QUERY: $query");
        }*/

That is not a valid fix for this issue, the issue is in fact an invalid query - note the empty parentheses in the OR statement.  Removing the exception does not fix the problem. 

Well I do know that it ain't the valid fix for it, but it worked out, at least for now. however, I'd be glad to hear the exact solution for this.

Wincent, i applaud your enthusiasm and wish you good luck, but for that size site, you'll need a very high spec dedicated server....

Thanks for your advice @Vextah

@Wincent Nobel,

Always glad to see more people using Elgg, but this post is essentially advertising, which is against our community policies.

Fortunately we have a dedicated space where you can share your Elgg-based site: https://community.elgg.org/showcase. Please do submit it there!

Take a look to this post, you can use the piece of the code that filters groups activity. https://community.elgg.org/discussion/view/2200450/how-to-combine-own-following-river-activity-tabs-into-one

Thanks @Javier

Your initial question didn't mention this though. As I understood it you were asking for a redirect on login.

No problem, still thanks for your time. But I'd be happy to know the answer of custom page redirect if you can provide so.

When I do "[wwwroot]/activity/owner/[username]"  I get a deprecated error. :-(