
Explanation/Reference:
Explanation:
DB1: MAXDOP
You can use the max degree of parallelism (MAXDOP) option to limit the number of processors to use in parallel plan execution.
DB2: LEGACY_CARDINALITY_ESTIMATION
The CE (Cardinality Estimation) predicts how many rows your query will likely return. The cardinality prediction is used by the Query Optimizer to generate the optimal query plan. With more accurate estimations, the Query Optimizer can usually do a better job of producing a more optimal query plan.
Legacy CE: For a SQL Server database set at compatibility level 120 and above, the CE version 70 can be can be activated by using the at the database level by using the ALTER DATABASE SCOPED CONFIGURATION.
Example:
ALTER DATABASE SCOPED CONFIGURATION
SET LEGACY_CARDINALITY_ESTIMATION = ON;
GO
Reference:
https://social.technet.microsoft.com/wiki/contents/articles/34718.new-sql-server-2016-scoped- configuration.aspx