SQL Server Performance Forum – Threads Archive
compatibility level performanceIs there any kind of performance hit if you decide to use a compatibility level of 80 or earlier when using SQL 2K5? Edit: (other than missing out on the performance gains of certain more efficient T-SQL statements)
assuming this is just a syntax check, rather than a choice of whether to use the 2K or 2K5 optimizer model, this part should not make a difference confirm this by checking the execution plans for each comp level. of course, there is always occasional peculiar behavior with each variation
Thank you for your reply Joe. Actually, hopefully more to the point, I was wondering if, for example, using compatibility level 80 on SQL 2005 required more overhead to implement than using compatibliity level 90. I want to know if there any disadvantages to using a legacy compatibility level, other than missing out on the new features.