The KEEPFIXED PLAN query hint is used in order to retain the original execution plan used to initially compile a statement. It is typically used to disallow a recompile, especially in regards to a statement that utilizes temp table or a table that changes it’s percentage of records frequently resulting in triggering a recompile for a statement.
To use, specify OPTION (KEEPFIXED PLAN) immediately after the statement that you do not want to recompile.
OPTION (KEEPFIXED PLAN)
Temp tables frequently recompile due to the change in statistics. When using temp tables within stored procedures, this can be a disadvantage. To get around the recompile, either use table variables (indexed with constraints) or use the KEEPFIXED PLAN query hint.
Recompiles typically happen when the percentage of a tables (or temp tables) rows change by 500 and the cardinality (or uniqueness) changes by 20%.