quote:
Thanks Jonathan,I read the paper (Automating Statistics Management for Query Optimizers ftp://ftp.research.microsoft.com/users/AutoAdmin/stats.pdf). Very **very** complex!
If I understand well, there's no simple rule of thumb. You have to try and to test (heuristic approach) and so on ...
Am I right?
Patrick SIMONS, MCP
Yes, that paper is quite technical... 
You can guess at some cases where creating statistics on multiple columns (which auto-stats does not do) might help; e.g. with multiple equalities in the join predicate, these heuristics could help the query optimizer better decide which table is probed in a hash join.
--Jonathan
--Jonathan