Also I think this would probably only make sense for TEMPORARY tables - otherwise you can get this sort of thing going on:
- you create a table and you have set a relation size limit - you commit and keep working - I add a whole lot of rows to your new table (taking it over the limit) - you go to add some more rows to this table...
you cannot to across session limit and is not important if you do inserts more times or once.
Sorry Pavel - what you have said above is difficult for me to understand - if the limit is intended as a *session* limit then concurrent activity from multiple sessions makes it behave - well - strangely to say the least, as tables are essentially shared resources.
I am sorry, I should to explain first our use case. Our product support multidimensional modelling - usually we have a few (less than 1000) unlimited user data tables. When user can to see some view (report), our engine generate 10 - 100 queries and result of these queries are stored in tables. Then result of one calculation can be shared between reports, users. These tables (caches) are semi temporal - life cycle is about hour, max days. Some queries in multidimensional analysis are Cartesian products - we are not able to estimate well a sizes of these tables - due free schema - users can create own logical model (users can fill these data freely) - and variability of generated queries is too long.