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sys.dm_exec_requests (Transact-SQL)

Returns information about each request that is executing within SQL Server.

Note

To execute code that is outside SQL Server (for example, extended stored procedures and distributed queries), a thread has to execute outside the control of the non-preemptive scheduler. To do this, a worker switches to preemptive mode. Time values returned by this dynamic management view do not include time spent in preemptive mode.

Column name

Data type

Description

session_id

smallint

ID of the session to which this request is related. Is not nullable.

request_id

int

ID of the request. Unique in the context of the session. Is not nullable.

start_time

datetime

Timestamp when the request arrived. Is not nullable.

status

nvarchar(30)

Status of the request. This can be of the following:

  • Background

  • Running

  • Runnable

  • Sleeping

  • Suspended

Is not nullable.

command

nvarchar(16)

Identifies the current type of command that is being processed. Common command types include the following:

  • SELECT

  • INSERT

  • UPDATE

  • DELETE

  • BACKUP LOG

  • BACKUP DATABASE

  • DBCC

  • WAITFOR

The text of the request can be retrieved by using sys.dm_exec_sql_text with the corresponding sql_handle for the request. Internal system processes set the command based on the type of task they perform. Tasks can include the following:

  • LOCK MONITOR

  • CHECKPOINTLAZY

  • WRITER

Is not nullable.

sql_handle

varbinary(64)

Hash map of the SQL text of the request. Is nullable.

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. Is nullable.

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_end_offset, and the sys.dm_exec_sql_text dynamic management function to retrieve the currently executing statement for the request. Is nullable.

plan_handle

varbinary(64)

Hash map of the plan for SQL execution. Is nullable.

database_id

smallint

ID of the database the request is executing against. Is not nullable.

user_id

int

ID of the user who submitted the request. Is not nullable.

connection_id

uniqueidentifier

ID of the connection on which the request arrived. Is nullable.

blocking_session_id

smallint

ID of the session that is blocking the request. If this column is NULL, the request is not blocked, or the session information of the blocking session is not available (or cannot be identified).

-2 = The blocking resource is owned by an orphaned distributed transaction.

-3 = The blocking resource is owned by a deferred recovery transaction.

-4 = Session ID of the blocking latch owner could not be determined at this time because of internal latch state transitions.

wait_type

nvarchar(60)

If the request is currently blocked, this column returns the type of wait. Is nullable.

wait_time

int

If the request is currently blocked, this column returns the duration in milliseconds, of the current wait. Is not nullable.

last_wait_type

nvarchar(60)

If this request has previously been blocked, this column returns the type of the last wait. Is not nullable.

wait_resource

nvarchar(256)

If the request is currently blocked, this column returns the resource for which the request is currently waiting. Is not nullable.

open_transaction_count

int

Number of transactions that are open for this request. Is not nullable.

open_resultset_count

int

Number of result sets that are open for this request. Is not nullable.

transaction_id

bigint

ID of the transaction in which this request executes. Is not nullable.

context_info

varbinary(128)

CONTEXT_INFO value of the session. Is nullable.

percent_complete

real

Percentage of work completed for the following commands:

  • ALTER INDEX REORGANIZE

  • AUTO_SHRINK option with ALTER DATABASE

  • BACKUP DATABASE

  • DBCC CHECKDB

  • DBCC CHECKFILEGROUP

  • DBCC CHECKTABLE

  • DBCC INDEXDEFRAG

  • DBCC SHRINKDATABASE

  • DBCC SHRINKFILE

  • RECOVERY

  • RESTORE DATABASE,

  • ROLLBACK

  • TDE ENCRYPTION

Is not nullable.

estimated_completion_time

bigint

Internal only. Is not nullable.

cpu_time

int

CPU time in milliseconds that is used by the request. Is not nullable.

total_elapsed_time

int

Total time elapsed in milliseconds since the request arrived. Is not nullable.

scheduler_id

int

ID of the scheduler that is scheduling this request. Is not nullable.

task_address

varbinary(8)

Memory address allocated to the task that is associated with this request. Is nullable.

reads

bigint

Number of reads performed by this request. Is not nullable.

writes

bigint

Number of writes performed by this request. Is not nullable.

logical_reads

bigint

Number of logical reads that have been performed by the request. Is not nullable.

text_size

int

TEXTSIZE setting for this request. Is not nullable.

language

nvarchar(128)

Language setting for the request. Is nullable.

date_format

nvarchar(3)

DATEFORMAT setting for the request. Is nullable.

date_first

smallint

DATEFIRST setting for the request. Is not nullable.

quoted_identifier

bit

1 = QUOTED_IDENTIFIER is ON for the request. Otherwise, it is 0.

Is not nullable.

arithabort

bit

1 = ARITHABORT setting is ON for the request. Otherwise, it is 0.

Is not nullable.

ansi_null_dflt_on

bit

1 = ANSI_NULL_DFLT_ON setting is ON for the request. Otherwise, it is 0.

Is not nullable.

ansi_defaults

bit

1 = ANSI_DEFAULTS setting is ON for the request. Otherwise, it is 0.

Is not nullable.

ansi_warnings

bit

1 = ANSI_WARNINGS setting is ON for the request. Otherwise, it is 0.

Is not nullable.

ansi_padding

bit

1 = ANSI_PADDING setting is ON for the request.

Otherwise, it is 0.

Is not nullable.

ansi_nulls

bit

1 = ANSI_NULLS setting is ON for the request. Otherwise, it is 0.

Is not nullable.

concat_null_yields_null

bit

1 = CONCAT_NULL_YIELDS_NULL setting is ON for the request. Otherwise, it is 0.

Is not nullable.

transaction_isolation_level

smallint

Isolation level with which the transaction for this request is created. Is not nullable.

0 = Unspecified

1 = ReadUncomitted

2 = ReadCommitted

3 = Repeatable

4 = Serializable

5 = Snapshot

lock_timeout

int

Lock time-out period in milliseconds for this request. Is not nullable.

deadlock_priority

int

DEADLOCK_PRIORITY setting for the request. Is not nullable.

row_count

bigint

Number of rows that have been returned to the client by this request. Is not nullable.

prev_error

int

Last error that occurred during the execution of the request. Is not nullable.

nest_level

int

Current nesting level of code that is executing on the request. Is not nullable.

granted_query_memory

int

Number of pages allocated to the execution of a query on the request. Is not nullable.

executing_managed_code

bit

Indicates whether a specific request is currently executing common language runtime objects, such as routines, types, and triggers. It is set for the full time a common language runtime object is on the stack, even while running Transact-SQL from within common language runtime. Is not nullable.

group_id

int

ID of the workload group to which this query belongs. Is not nullable.

query_hash

binary(8)

Binary hash value calculated on the query and used to identify queries with similar logic. You can use the query hash to determine the aggregate resource usage for queries that differ only by literal values. For more information, see Finding and Tuning Similar Queries by Using Query and Query Plan Hashes.

query_plan_hash

binary(8)

Binary hash value calculated on the query execution plan and used to identify similar query execution plans. You can use query plan hash to find the cumulative cost of queries with similar execution plans. For more information, see Finding and Tuning Similar Queries by Using Query and Query Plan Hashes.

Permissions

Requires VIEW SERVER STATE permission on the server.

Note

If the user has VIEW SERVER STATE permission on the server, the user will see all executing sessions on the instance of SQL Server; otherwise, the user will see only the current session.

Examples

A. Finding the query text for a running batch

The following example queries sys.dm_exec_requests to find the interesting query and copy its sql_handle from the output.

SELECT * FROM sys.dm_exec_requests;
GO

Then, to obtain the statement text, use the copied sql_handle with system function sys.dm_exec_sql_text(sql_handle).

SELECT * FROM sys.dm_exec_sql_text(< copied sql_handle >);
GO

B. Finding all locks that a running batch is holding

The following example queries sys.dm_exec_requests to find the interesting batch and copy its transaction_id from the output.

SELECT * FROM sys.dm_exec_requests;
GO

Then, to find lock information, use the copied transaction_id with the system function sys.dm_tran_locks.

SELECT * FROM sys.dm_tran_locks 
WHERE request_owner_type = N'TRANSACTION' 
    AND request_owner_id = < copied transaction_id >;
GO

C. Finding all currently blocked requests

The following example queries sys.dm_exec_requests to find information about blocked requests.

SELECT session_id ,status ,blocking_session_id
    ,wait_type ,wait_time ,wait_resource 
    ,transaction_id 
FROM sys.dm_exec_requests 
WHERE status = N'suspended';
GO