SQL Server Performance Forum – Threads Archive

compatibility level performance

Is 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)

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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

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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.

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