[mysterydip]

Maybe I'm misunderstanding, but you said anything goes, so here goes:

If rerunning entire queries is the problem, can you implement a changes table (could potentially double as an audit table if desired) which on a basic level just has time and rowid. Then you poll that table for anything newer than your current timestamp. Say for a report with 1000 rows, only 2 have changed in the last second. Then you can just do a query of the big table on those exact rowids.

The benefit over having timestamp in the big table is the changes table can be kept to a minimal size. You don't need to store any more than, say, a minute's worth of changes. Anyone visiting the page for the first time or that far out of sync will poll the whole report.