![]() ![]() Listing 7-1 is a stored procedure which in the middle of the procedureĬhanges the CONCAT_NULL_YIELDS_NULL option. The code in Listing 7-1 is extremely simple, but it Recompilation happens because a SET option changes, the executable plan will be Recompilation affects only a small portion of the procedure. Other words, the whole procedure is recompiled even if the cause of the Or batch is large, because SQL Server 2000 does module-level recompilation. Things that cause recompilation to occur are as follows:ħ-2: Trace Properties Dialog for SQL ProfilerĪ recompilation can incur a huge cost especially if the procedure, function, Problem with executing stored procedures, and that is recompilation. Has very much improved the execution of not only stored procedures butįunctions, batches, dynamic queries, and so on. This architecture, paired with the fact that the execution context is reused, This data structure, which is called the executable plan orĮxecution context, holds the data specific to each user's execution, such Query plan in memoryone copy for all serial executions and another for allĮxecutable plan≺ data structure for each user that concurrentlyĮxecutes the query. There are never more than one or two copies of the The plan and no user context information (such as data variable values) is The plan is reentrant, which implies that all users share query plan)≺ read-only data structure used byĪny number of users. Is divided into two structures: a compiled plan and an executable plan.Ĭompiled plan (a.k.a. Server 2000, the query plan architecture differs from previous versions, and it Of the infrastructural improvements in T-SQL: statement recompilation. The next thing we'll look at is a performance enhancement that is part Learn More Buy Statement-Level Recompilation First Look at SQL Server 2005 for Developers, A
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