Well what i'm trying to do is to bump the logs when someone make comments on them.

If someone comment on one old post, i want it to appear in first position on river. I'm trying a new approach now with Ajax. I will get the timestamp of the comments rather than the timestamp from the original post, and bring the whole post to the first position.

kk.... -> wrong solution ;) u shud do yr data-analysis 1st b4 zapping all over the db strucs ! undo ;-) al those code changes related to the db table, restore the table struc and.. study (thoroughly) how the current strucs & logic cater for river/comments fetches & displays - *then find another better easier way to achieve this.

If someone comment on one old post, i want it to appear in first position on river.

Ok, now I see the logic. I suppose this could be useful.

But still, creating a new column to the database table is a bad idea. You already have an entry in the database for each comment that the users have made. There is no need to add or update any data.

So instead of moving the commented river object to the top of the river, just try to change the way how the new comments are displayed.