Is it worth the trouble to use tinyint instead of int for SqlServer lookup tables?

Question

When designing a lookup table (enum) in SqlServer 2005, if you know the number of entries will never get very high, should you use tinyint instead of int? I\'m most concerned a

Answer 1

The narrower a table (or index node entry) is, the more records (or index nodes) can fit on a single IO page, and the fewer physical (and logical) reads IO operations are required for any query. Also, the more index nodes there are on a single page, the fewer levels there may be in the index, from root to leaf level, and if by making a table narrower you pass the threshold where the index can be one level smaller, this can have a dramatic effect on perforamnce.

If by switching to TinyInt you change your table from 200 bytes wide to 197 bytes wide, it probably won't make any difference... But if you change it from 20 bytes to 14, (say you have 2 ints in there), then it could be dramatic...