sys.dm_exec_cursors (Transact-SQL)

مقالة
05/16/2013

Returns information about the cursors that are open in various databases.

Syntax

dm_exec_cursors (session_id | 0 )

Arguments

session_id | 0
ID of the session. If session_id is specified, this function returns information about cursors in the specified session.

If 0 is specified, the function returns information about all cursors for all sessions.

Table Returned

Column name	Data type	Description
session_id	int	ID of the session that holds this cursor.
cursor_id	int	ID of the cursor object.
name	nvarchar(256)	Name of the cursor as defined by the user.
properties	nvarchar(256)	Specifies the properties of the cursor. The values of the following properties are concatenated to form the value of this column: Declaration Interface Cursor Type Cursor Concurrency Cursor scope Cursor nesting level For example, the value returned in this column might be "TSQL \| Dynamic \| Optimistic \| Global (0)".
sql_handle	varbinary(64)	Handle to the text of the batch that declared the cursor.
statement_start_offset	int	Number of characters into the currently executing batch or stored procedure at which the currently executing statement starts. Can be used together with the sql_handle, the statement_end_offset, and the sys.dm_exec_sql_text dynamic management function to retrieve the currently executing statement for the request.
statement_end_offset	int	Number of characters into the currently executing batch or stored procedure at which the currently executing statement ends. Can be used together with the sql_handle, the statement_start_offset, and the sys.dm_exec_sql_text dynamic management function to retrieve the currently executing statement for the request.
plan_generation_num	bigint	A sequence number that can be used to distinguish between instances of plans after recompilation.
creation_time	datetime	Timestamp when this cursor was created.
is_open	bit	Specifies whether the cursor is open.
is_async_population	bit	Specifies whether the background thread is still asynchronously populating a KEYSET or STATIC cursor.
is_close_on_commit	bit	Specifies whether the cursor was declared by using CURSOR_CLOSE_ON_COMMIT. 1 = Cursor will be closed when the transaction ends.
fetch_status	int	Returns last fetch status of the cursor. This is the last returned @@FETCH_STATUS value.
fetch_buffer_size	int	Returns information about the size of the fetch buffer. 1 = Transact-SQL cursors. This can be set to a higher value for API cursors.
fetch_buffer_start	int	For FAST_FORWARD and DYNAMIC cursors, it returns 0 if the cursor is not open or if it is positioned before the first row. Otherwise, it returns -1. For STATIC and KEYSET cursors, it returns 0 if the cursor is not open, and -1 if the cursor is positioned beyond the last row. Otherwise, it returns the row number in which it is positioned.
ansi_position	int	Cursor position within the fetch buffer.
worker_time	bigint	Time spent, in microseconds, by the workers executing this cursor.
reads	bigint	Number of reads performed by the cursor.
writes	bigint	Number of writes performed by the cursor.
dormant_duration	bigint	Milliseconds since the last query (open or fetch) on this cursor was started.

Permissions

Requires VIEW SERVER STATE permission on the server.

Remarks

The following table provides information about the cursor declaration interface and includes the possible values for the properties column.

Property	Description
API	Cursor was declared by using one of the data access APIs (ODBC, OLEDB).
TSQL	Cursor was declared by using the Transact-SQL DECLARE CURSOR syntax.

The following table provides information about the cursor type and includes the possible values for the properties column.

Type	Description
Keyset	Cursor was declared as Keyset.
Dynamic	Cursor was declared as Dynamic.
Snapshot	Cursor was declared as Snapshot or Static.
Fast_Forward	Cursor was declared as Fast Forward.

The following table provides information about cursor concurrency and includes the possible values for the properties column.

Concurrency	Description
Read Only	Cursor was declared as read-only.
Scroll Locks	Cursor uses scroll locks.
Optimistic	Cursor uses optimistic concurrency control.

The following table provides information about cursor scope and includes the possible values for the properties column.

Scope	Description
Local	Specifies that the scope of the cursor is local to the batch, stored procedure, or trigger in which the cursor was created.
Global	Specifies that the scope of the cursor is global to the connection.

Examples

A. Detecting old cursors

This example returns information about cursors that have been open on the server longer than the specified time of 36 hours.

SELECT creation_time, cursor_id, name, c.session_id, login_name 
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()) > 36;
GO

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