Unique identifier (guid) as primary key in database design

Question

Our data resides in a SQL Server 2008 database, there will be a lot queries and joinings between tables. We have this argument inside the team, some are arguing use of integ

Answer 1

The big problem with GUIDs as primary keys is that they cause massive table fragmentation, which can be a big performance issue (the larger the table, the larger the issue). Even as a key for a nonclustered index, they will cause index fragmentation.

You can partly mitigate the problem by setting an appropriate fill factor -- but it will still be an issue.

The size difference doesn't bother me that much, except on tables with otherwise narrow rows where table scans are also required. In those cases, being able to fit more rows per DB page is a performance advantage.

There can be good reasons to use GUIDs, but there is also a cost. I generally prefer INT IDENTITY for primary keys, but I don't avoid GUIDs when they are a better solution.