For reference:
- 9481 – Use when running SQL Server 2014 with the default database compatibility level 120. Trace flag 9481 forces the query optimizer to use version 70 (the SQL Server 7.0 through SQL Server 2012) of the cardinality estimator when creating the query plan.
- 2312 – Use when running SQL Server 2014 with database compatibility level 110, which is the compatibility level for SQL Server 2012. Trace flag 2312 forces the query optimizer to use version 120 (the SQL Server 2014 and later) of the cardinality estimator when creating the query plan.