Sql option recompile how to#

After you run the query and the execution plan shows up, you will see a “Parallelism” step. Here are a couple ways that I use to find out if parallelism is happening to a query. How Do You Know If Your Query Is Using Parallelism? You will need to test your query before and after to see if there is significant improvement. But occasionally if you are having a slow query, you can try changing the MAXDOP setting. This is usually the fastest/best way for your query to execute. In most cases you will just want SQL Server to manage the parallelism. Is MAXDOP a silver bullet for making queries faster? No.

Will Removing MAXDOP Help My Queries Run Faster You can see that it now uses parallelism. Here is a screenshot of the execution plan of that exact same query without specifying the MAXDOP. To show how this affects the query, let me show you the execution plan when I supply the MAXDOP 1.

Sql option recompile how to#

Here is an example of how to use the MAXDOP query hint to limit the number of parallel threads to 1 (essentially disabling the parallelism): In fact, the word MAXDOP stand for “ Maximum Degree Of Parallelism”. When you use MAXDOP, you will specify the maximum number of parallelism threads that SQL Server uses for that query. MAXDOP is a query hint that can be added to the end of your SQL query to control the amount of parallelism that happens. Sometimes this can be a longer task then just using 1 processor the whole time. What this means is that when a query is split among different processors, it will need to merge them back together before it sends it to you. Sometimes the time that it takes to reassemble the results is longer than the not using parallelism.Sometimes the parallelism can take away CPU from other processes that are trying to run at the same time.A couple issues I have ran in to in our production environment are: Okay… this is great, right?Īlthough the thought of running 1 SQL query but using multiple processors sounds great, sometimes it can actually sometimes cause slower queries. The default setting in SQL Server will use the number of CPU cores on the system as the maximum number of parallel processors to use. That means that SQL Server will split up the execution of a query among different CPUs if it thinks that it can get the query results faster that way. Since we can't prevent which company will the first one used after the plans are re-generated, we're trying to force the recompile down the pipe so we can prevent users from catching dust while awaiting for their search results.SQL Server comes with built-in support for using parallelism for query execution. We noticed in those cases that the query generated by AX included the 'recompile' keyword. We flushed the plans, go back to the same screen but this time start by doing searches in a company with a large number of transactions. When I say slow, I mean 30+ seconds to do a search in a invoices grid instead of less than one second! Then when we switched to a company having a large number of transactions, things slow down to a crawl because the newly created plan is not optimized for a large number of transactions. We're able to repriduce the problem in a DEV environnement by using the problematic entry screen first in a low transaction company. Some of the companies have a large number of transactions and others, well not so much. We have multiple companies in our AX installation.

When query plans are flushed (aither forcibly or by the regular SQL Server management process), it's a lucky shot for the re-creation of some query plans. Dynamics Previous Versions Dynamics Previous Versions.Implementing Dynamics 365 Implementing Dynamics 365.Artificial Intelligence Artificial Intelligence.Dynamics 365 Products Dynamics 365 Products.