Sql option recompile

Not sure what parameter sniffing is? Learn from this blog post or this 50 minute free video.

Here are some problems you can hit with recompile. Not necessarily caused by recompile, but by not re-using plans. Those are very real problems that I see on client systems pretty frequently. But all that assumes that those options are immediately available. You can always yoink it out later.

Sql option recompile

Today is the last blog post of the year and this is also a final blog post in the series of Parameter Sniffing which I have been writing. I strongly recommend that you read my earlier blog posts on this topic before you consider the option of recompile suggested in this blog post. Before continuing this blog post, I strongly suggest that you read the following blog posts to get an understanding of the background of the concept which I am going to discuss today. Here is what we have learned so far. It is extremely easy to overcome the problem of parameter sniffing. However, it is extremely difficult to overcome the performance problem which is introduced due to the parameter sniffing issue. There is no sure solution to overcome the problem if your stored procedure has sniffed the parameter and used that to build the execution plan. It is quite possible that even though we use the average value due to statistics the performance problem has yet not resolved. While many want to argue that this may be very bad advice, there are moments where it has been amazing advice as well. In SQL Server there is no right or wrong answer unless while using production we are facing the negative consequence of it. It is important to know how each feature works and with the same spirit let us see how option recompile can help us in certain situations. Next, let us run the following two stored procedures with two different parameters. When we see the execution plan of the queries you will notice that this time the execution plan has a correct estimation of the rows and accordingly the query is consuming the resources which are needed to optimize that particular execution plan. When the query needs more resources, it takes more resources and when needed fewer resources, it uses appropriate resources. This is a great adjustment and SQL Server makes every single time when the stored procedure is executed.

The RetrievedFromCache attribute will be shown as false. I thought about some type of logic that could detect when those procedures are not doing well and sql option recompile off the recompile then. Altering a stored procedure causes the query plan entry for the stored procedure to be removed from the plan cache.

This article intends to give comprehensive details on how we can use the recompilation options of SQL Server stored procedures and how they behave when we use these recompilation options. A stored procedure is a ready T-SQL code that can be reused again and again. The most essential benefits of using stored procedures can be listed as follows:. Performance: After the first execution of the stored procedure, the query optimizer creates an execution plan and this plan is stored in the query plan cache. So that, all next executions of the same SQL Server stored procedure will use this cached stored procedure. This methodology aims to avoid an unnecessary query compilation process. Code reuse: The SQL stored procedure helps to avoid rewriting the same codes again and again.

When an application submits a query to the SQL Server database engine for the first time, a query plan is prepared and complied in order to execute it and then the plan is stored in memory. In subsequent executions of the query, SQL Server will try to re-use this optimized plan from the query plan cache. When SQL Server tries to use this query plan it might find issues or changes that require a recompilation. Due to the recompilation, performance can be impeded. There are a number of reasons why a query recompilation can occur which I will describe in this tip. To better understand recompilations, first we will look at the compilation and caching mechanism that SQL Server uses. At a high level, the query processor goes through multiple phases before producing a query plan in SQL Server. First it parses and normalizes the SQL Server statements then it compiles and optimizes the statements. After that, as a part of the query execution process, the query plan is generated and stored in memory.

Sql option recompile

Today, I want to address a few of the comments as well as continue with a few tips and tricks using these commands. And, once again, we see the optimal plan to use the index and do a bookmark lookup because this query is highly selective only 1 row. In fact, we can see that from checking our plan cache as well:. Even though this is the third time we have executed this statement, this final execution was NOT put in cache. And, it will NOT affect future executions.

Nch sofware

Hi Bent, Forgot my question, I found error in collection procedure. I do NOT recommend using this command in any regular jobs, automated processes, or production code. These two events prove that SQL Server stored procedures are compiled in their first execution. Submit and view feedback for This product This page. The looped execution with and without recompile does seem like a simpler way to test. Nic Neufeld. Any advise to solve it or debug the cause? The usage of this procedure is very simple, we only pass the procedure name into this system procedure. WHERE [ sqlserver ]. Hi , I need your help to clarify the compilation of SP and Function. Make sense? Yes, I was thinking of doing something like that, with a load test server, running a captured replay trace with both versions of the proc repeatedly while monitoring CPU load. I thought about some type of logic that could detect when those procedures are not doing well and kicking off the recompile then.

Not sure what parameter sniffing is? Learn from this blog post or this 50 minute free video. You must decide: what hint or command do you use, and where do you put it?

Additional resources In this article. However, these options cause the creation of a new execution plan. Performance: After the first execution of the stored procedure, the query optimizer creates an execution plan and this plan is stored in the query plan cache. This does not execute the procedure but it does mark the procedure to be recompiled so that its query plan is updated the next time that the procedure is executed. One option that I love for quick and easy testing is the ability to call a stored procedure with a recompile hint at execution time. Note that the common misconception of table variables being in memory and temp tables being on disk is inaccurate. The simplest thing in terms of showing managers is just to run it in a tight loop with the hint and show the CPU chart, and then run it without and show the CPU chart. If the results are purely being returned in a select, then the correct number of rows will be estimated. Can someone give me an example? If the answer is the right solution, please click "Accept Answer" and kindly upvote it. Any Advice you can give? As for recompiles, I agree. When a procedure is compiled for the first time or recompiled, the procedure's query plan is optimized for the current state of the database and its objects.