How to Check for Unreleased Cursors in SQL Server?

In our last post, we talked about how to obtain the start and end time of mysql binlogs. Toaday, let's see how to  check for unreleased cursors in SQL Server.

I’ve never been particularly enthusiastic about using cursors in SQL Server and rarely use them. Recently, a user asked how to check for unreleased cursors in the database, which seemed interesting, so I tested and verified it, and organized my findings here.

Session 1: We simulate an application or script where a cursor is opened but not closed or released.

DECLARE Cursor_Test CURSOR FOR
SELECT * FROM dbo.TEST;
OPEN Cursor_Test;

So, how can we check for unreleased cursors in the database? SQL Server provides a dynamic management function called sys.dm_exec_cursors, which returns information about open cursors in various databases.

SELECT * FROM sys.dm_exec_cursors(0)

For details on the columns returned by this dynamic management function, refer to the MSDN documentation, as the columns may vary by SQL Server version. To find cursors that are still open, you can filter the results by the is_open field (where 1 indicates open, and 0 indicates closed).

Session 2: Checking for Unclosed Cursors

SELECT  session_id ,
        cursor_id ,
        name ,
        creation_time ,
        is_open
FROM    sys.dm_exec_cursors(0)
WHERE   is_open = 1;

If you want to see cursors that have been closed but not released, you can close the cursor in Session 1 using CLOSE Cursor_Test; but avoid releasing it.

SELECT  session_id ,
        cursor_id ,
        name ,
        creation_time ,
        is_open
FROM    sys.dm_exec_cursors(0)
WHERE   is_open = 0;

Additionally, you can use the following SQL to view information on cursors that have been open longer than a specified time (e.g., 1 hour), adjusting the query conditions as needed.

SELECT   creation_time
        ,cursor_id 
        ,name 
        ,c.session_id 
        ,login_name 
        ,c.creation_time 
        ,c.is_open
FROM    sys.dm_exec_cursors (0) AS c
        JOIN sys.dm_exec_sessions AS s ON c.session_id = s.session_id
WHERE   DATEDIFF(hh, c.creation_time, GETDATE()) > 1;
GO