Data warehouse design, fact to dimention row count ratio
Posted on 2007-11-16
We are working on a data warehouse project for one of our customers. We are now towards the end of the project and have real data going into the warehouse. The database has 13 dimensions and a fact table with 62 attributes. Currently the fact table has 7 million records in it and most of the dimensions are less than 10k rows in size. However, 2 of the dimensions have 400k rows which is about 5.5% of the rows in the fact table i have been monitoring both tables for a month now and conclude that they are always around 5 or 6% of the fact table.
Is this an acceptable growth for a dimension table? I am worried that the growth of these tables will become an issue later down the line as the data in the system now is only a snippet whats to be loaded before production. The only solution would be to merge the 2 big dimensions into the fact table, but this would mean having some non numeric attributes in the call fact table.