I am designing a database for a potentially large data warehouse. Several of the fact tables may contain over a hundred columns. Some of these columns may be sparse since data extracted from various sources may have different attribute. We are debating between
1) Keep all columns and deal with sparseness. A few colleagues of mine worried about tables being sparse, but I don't see any problem with it. Perhaps I misses some important thing here. Would the width (number of columns) of a table have any impact on performance that much?
2) Move sparse columns into an EAV table. Queries will be more expensive, but how much more? Would you use this model in your own data warehouse?
I am not familiar enough with datawarehouse performance and think I would post this question ot the gurus in this community.
Thanks for your comments in advance!