![]() ![]() This will allow the optimizer to know how many rows are in the table variable. Therefore, to improve the performance of your code that use table variables that contain lots of rows, you should consider adding the optimizer hint RECOMPILE as shown below: SELECT O., TV.īy adding the optimizer hint RECOMPILE, a statement that uses a table variable will be recompiled after the temporary table has been populated. Operators that perform well for small numbers of rows do not always scale when large numbers of rows are involved. Having an estimated row count of 1 works well for operators that have small row counts, like a NESTED LOOP operator for a join operation. This occurs because table variables don’t have statistics. This is because when a batch is compiled the table variable has yet to be populated with any rows, and therefore the optimizer uses an estimated row count of 1 for table variables. The following example causes stored procedures, triggers, and user-defined functions that act on the Sales.Customer table to be recompiled the next time that they are run.Table Variables have been known to run slowly when the table variable contains lots of rows. Requires ALTER permission on the specified object. For more issues and discussion on this topic, see Resolving queries with parameter sensitive plan problems.Apply the WITH RECOMPILE option with a Query Store hint without making code changes.Apply the WITH RECOMPILE option with a plan guide.Append the WITH RECOMPILE option to the query, requiring a code change.In prior versions, instead of calling sp_recompile with each execution, consider: The feature Parameter Sensitive Plan optimization introduced in SQL Server 2022 (16.x) attempts to mitigate this problem automatically. Recompiling a stored procedure with every execution is one of the less efficient ways to combat query plan issues caused by parameterization. Most commonly, automatic recompilation follows changes to the underlying cardinality estimate because of automatic or manual statistics updates. ![]() There are a variety of reasons the database engine may choose to recompile objects. SQL Server automatically recompiles stored procedures, triggers, and user-defined functions when it is advantageous. Proactive execution of this stored procedure is usually unnecessary. By recompiling stored procedures and triggers that act on a table, you can reoptimize the queries. As indexes or other changes that affect statistics are made to the database, compiled stored procedures, triggers, and user-defined functions may lose efficiency. The queries used by stored procedures, or triggers, and user-defined functions are optimized only when they are compiled. Sp_recompile looks for an object in the current database only. Return Code ValuesĠ (success) or a nonzero number (failure) Remarks If object is the name of a table or view, all the stored procedures, triggers, or user-defined functions that reference the table or view will be recompiled the next time that they are run. If object is the name of a stored procedure, trigger, or user-defined function, the stored procedure, trigger, or function will be recompiled the next time that it is run. object is nvarchar(776), with no default. The qualified or unqualified name of a stored procedure, trigger, table, view, or user-defined function in the current database. Transact-SQL syntax conventions Syntax sp_recompile 'object' In a SQL Server Profiler collection, the event SP:CacheInsert is logged instead of the event SP:Recompile. It does this by dropping the existing plan from the procedure cache forcing a new plan to be created the next time that the procedure or trigger is run. Applies to: SQL Server Azure SQL Database Azure SQL Managed InstanceĬauses stored procedures, triggers, and user-defined functions to be recompiled the next time that they are run. ![]()
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