Sql option recompile

Sheldon Hull This will probably be a multiple stage discussion.

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. Or whatever.

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.

In which Phil illustrates an old trick using STUFF sql option recompile intert a number of substrings from a table into a string, and explains why the technique might speed up your code Contrary to the notion that stored procedures are compiled during their initial creation, stored procedures are compiled on their first execution.

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.

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. Now, the other two questions — these are a lot more interesting and this is where I think that stored procedures should be used. Personally, I think that developers that know the data and know the application — will be a lot better at creating the RIGHT code especially when they understand all of the options available to them. However, this is also where things get more challenging. And, there are really a couple of options at this point.

Sql option recompile

Upgrade to Microsoft Edge to take advantage of the latest features, security updates, and technical support. Query hints specify that the indicated hints are used in the scope of a query. They affect all operators in the statement. Error occurs if one or more query hints cause the Query Optimizer not to generate a valid plan. Because the SQL Server Query Optimizer typically selects the best execution plan for a query, we recommend only using hints as a last resort for experienced developers and database administrators. Transact-SQL syntax conventions. If you specify more than one join hint, the optimizer selects the least expensive join strategy from the allowed ones.

Waylon mercy

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. I agree this covers the topic very well. Sign in to follow. This tells SQL Server to recompile this statement every time it is executed. The developers are putting allot of logic in the procedures. This option is a bit more work, but it has a much better payoff over time. Leave new tobi. If a database undergoes significant changes to its data or structure, recompiling a procedure updates and optimizes the procedure's query plan for those changes. This typically includes queries with joins, parallelism decisions, and index selection choices… Queries that modify table variables do not generate parallel query execution plans. This post is a great resource.

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.

This browser is no longer supported. You can always yoink it out later. I assume the issue is parameter sensitivity causing a bad plan every now and then. One during peak hours executes between times an hour and the other between times per hour. However every time that happens, some critical jobs that are executed in a daily basis late at night become incredible slow taking more than the double of the time to complete. However, temp tables allow some behaviors that can cause plan recompilation incurring more CPU overhead each time. Leave new tobi. Author Recent Posts. Should I use option recompile? I've got a few more thoughts on the topic this week, and I look forward to your comments. In some cases parameter sniffing , we need to generate a fresh query plan for every execution of the SQL Server stored procedure. The most essential benefits of using stored procedures can be listed as follows:. I am not able to stop this so I have to live with it.