October 6, 2025 at 4:41 am
if sp_executesql does my job then where exactally sp_prepare and sp_execute comes in to picture ( theortically it says sp_executesql only resues the plan it is cache and plan cache evicts unused plan first)
October 7, 2025 at 5:10 am
Thanks for posting your issue and hopefully someone will answer soon.
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October 18, 2025 at 7:37 am
When you use sp_executesql, SQL Server does something quite intelligent. It creates a query plan for that statement the first time it runs and keeps that plan in the plan cache. If the same statement is executed again, with the same structure and parameter types, SQL Server will reuse that existing plan instead of compiling a new one. This makes it efficient for loops, stored procedures, and even calls coming from .NET code.
Now, about plan eviction. SQL Server does not remove cached plans in a simple first-in-first-out manner. It uses a least-recently-used (LRU) approach. That means a plan that’s used frequently will stay in cache longer, while plans that haven’t been used recently are the first to be aged out when memory pressure increases. So, if your loop keeps using the same sp_executesql statement repeatedly, that plan remains active in cache and continues to be reused.
Then why do we even have sp_prepare and sp_execute? Those come into play when you are executing the same query multiple times within the same session, such as in a high-frequency loop or an application that sends a large number of identical queries one after another. In that case, you can “prepare” the statement once, which generates and stores the plan, and then execute it repeatedly using sp_execute without SQL Server having to recompile or even revalidate the query each time. It saves a small bit of overhead per call, which can add up in high-volume scenarios.
In simpler terms:
sp_executesql is ideal for loops, stored procedures, or any repeated query across multiple sessions. The plan gets cached and reused automatically.
sp_prepare and sp_execute are better when the same connection is executing the same query thousands of times and you want to minimize parsing and compilation costs inside that single session.
For most workloads and loops inside stored procedures or application calls, sp_executesql is enough. It already reuses the plan efficiently, and you don’t have to deal with extra prepare or execute handles. sp_prepare makes sense only when you are working with extremely tight loops, where every microsecond counts, or when you are managing the execution plan lifecycle manually.
So.. if your goal is simply to avoid recompilation and reuse cached plans, sp_executesql will do that reliably. sp_prepare and sp_execute are more about say micro-Optisation for very specific, high-frequency scenarios.
Let me give you example of all 3 for better understanding:
1. Regular Dynamic SQL (no plan reuse)
DECLARE @i INT = 1
WHILE @i <= 5
BEGN
DECLARE @sql NVARCHAR(MAX)
SET @sql = 'SELECT * FROM Sales.SalesOrderHeader WHERE SalesOrderID = ' + CAST(@i AS NVARCHAR(10))
EXEC(@sql);
SET @i += 1
END
Explanation:
Every loop iteration builds a different text string, so SQL Server treats it as a new statement.
Each run causes a new compile and plan generation, which means no plan reuse.
This is the slowest approach when executed many times.
Using sp_executesql (plan reuse enabled);;;
DECLARE @i INT = 1
WHILE @i <= 5
BEGIN
EXEC sp_executesql
N'SELECT * FROM Sales.SalesOrderHeader WHERE SalesOrderID = @OrderID',
N'@OrderID INT',
@OrderID = @i
SET @i += 1
END
Explanation:
Here the query text and parameter structure remain identical each time.
SQL Server compiles the plan once, caches it, and simply reuses it on subsequent executions.
You still get parameterization, security (against SQL injection), and plan reuse — all in one.
In almost all practical use cases — stored procedures, loops, or .NET calls — this is the right way to do it.
Using sp_prepare and sp_execute ---> Please note it is always used in paid..
DECLARE @handle INT
-- Step 1: Prepare the statement once
EXEC sp_prepare @handle OUTPUT,
N'@OrderID INT',
N'SELECT * FROM Sales.SalesOrderHeader WHERE SalesOrderID = @OrderID'
-- Step 2: Execute the prepared plan multiple times
EXEC sp_execute @handle, @OrderID = 1
EXEC sp_execute @handle, @OrderID = 2
EXEC sp_execute @handle, @OrderID = 3
EXEC sp_execute @handle, @OrderID = 4
EXEC sp_execute @handle, @OrderID = 5
-- Step 3: Deallocate when done
EXEC sp_unprepare @handle
Explanation:
Here, SQL Server prepares the query once, stores the compiled plan, and executes it multiple times using the handle.
This avoids even the small lookup and validation cost that sp_executesql performs.
However, it’s typically used by client libraries like ADO.NET, JDBC, or ODBC — you rarely need it inside T-SQL scripts unless you are doing very high-frequency execution in the same session.
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