I have an old SQL Server database that has been migrated a few times since < 2005. Some queries are running very slowly. I have been advised that the following changes could help performance:
- Increase the database compatibility level from 90 (2005) to highest possible (the software itself does support the highest).
Legacy Cardinality Estimationto ON.
Query Optimizer Fixesto ON.
Can these changes be made without taking users offline?