sp_server_diagnostics (Transact-SQL)

Article
05/16/2013

Captures diagnostic data and health information about SQL Server to detect potential failures. The procedure runs in repeat mode and sends results periodically. It can be invoked from either a regular or a DAC connection.

Topic link icon Transact-SQL Syntax Conventions

Syntax

sp_server_diagnostics [@repeat_interval =] 'repeat_interval_in_seconds'

Arguments

[ @repeat_interval =] 'repeat_interval_in_seconds'
Indicates the time interval at which the stored procedure will run repeatedly to send health information.

repeat_interval_in_seconds is int with the default of 0. The valid parameter values are 0, or any value equal to or more than 5. The stored procedure has to run at least 5 seconds to return complete data. The minimum value for the stored procedure to run in the repeat mode is 5 seconds.

If this parameter is not specified, or if the specified value is 0, the stored procedure will return data one time and then exit.

If the specified value is less than the minimum value, it will raise an error and return nothing.

If the specified value is equal to or more than 5, the stored procedure runs repeatedly to return the health state until it is manually canceled.

Return Code Values

0 (success) or 1 (failure)

Result Sets

sp_server_diagnostics returns the following information

Column	Data type	Description
creation_time	Datetime	Indicates the time stamp of row creation. Each row in a single rowset has the same time stamp.
component_type	Sysname	Indicates whether the row contains information for the SQL Server instance level component or for an AlwaysOn availability group: instance alwaysOn:AvailabilityGroup
component_name	Sysname	Indicates the name of component or the name of the availability group: system resource query_processing io_subsystem events <name of the availability group>
state	Int	Indicates the health status of the component: 0 1 2 3
state_desc	Sysname	Describes the state column. Descriptions that correspond to the values in the state column are: 0:Unknown 1:clean 2:warning 3:error
data	Varchar (max)	Specifies data that is specific to the component.

Here are the descriptions of the five components:

system: Collects data from a system perspective on spinlocks, severe processing conditions, non-yielding tasks, page faults, and CPU usage. This information is produces an overall health state recommendation.
resource: Collects data from a resource perspective on physical and virtual memory, buffer pools, pages, cache and other memory objects. This information produces an overall health state recommendation.
query_processing: Collects data from a query-processing perspective on the worker threads, tasks, wait types, CPU intensive sessions, and blocking tasks. This information produces an overall health state recommendation.
io_subsystem: Collects data on IO. In addition to diagnostic data, this component produces a clean healthy or warning health state only for an IO subsystem.
events: Collects data and surfaces through the stored procedure on the errors and events of interest recorded by the server, including details about ring buffer exceptions, ring buffer events about memory broker, out of memory, scheduler monitor, buffer pool, spinlocks, security, and connectivity . Events will always show 0 as the state.
<name of the availability group>: Collects data for the specified availability group (if component_type = "alwaysOn:AvailabilityGroup").

Remarks

From a failure perspective, the system, resource, and query_processing components will be leveraged for failure detection while the io_subsystem and events components will be leveraged for diagnostic purposes only.

The following table maps the components to their associated health states.

Components	Clean (1)	Warning (2)	Error (3)	Unknowns (0)
system	x	x	x
resource	x	x	x
query_processing	x	x	x
io_subsystem	x	x
events				x

The (x) in each row represents valid health states for the component. For example, io_subsystem will either show as clean or warning. It will not show the error states.

Permissions

Requires VIEW SERVER STATE permission on the server.

Examples

It is best practice to use the extended sessions to capture the health information and save it to a file that is located outside of SQL Server. Therefore, you can still access it if there is a failure. The following example saves the output from an event session to a file:

CREATE EVENT SESSION [diag]
ON SERVER
           ADD EVENT [sp_server_diagnostics_component_result] (set collect_data=1)
           ADD TARGET [asynchronous_file_target] (set filename='c:\temp\diag.xel')
GO
ALTER EVENT SESSION [diag]
      ON SERVER STATE = start
GO

The example query below reads the extended session log file:

SELECT
    xml_data.value('(/event/@name)[1]','varchar(max)') AS Name
  , xml_data.value('(/event/@package)[1]', 'varchar(max)') AS Package
  , xml_data.value('(/event/@timestamp)[1]', 'datetime') AS 'Time'
  , xml_data.value('(/event/data[@name=''component_type'']/value)[1]','sysname') AS Sysname
  , xml_data.value('(/event/data[@name=''component_name'']/value)[1]','sysname') AS Component
  , xml_data.value('(/event/data[@name=''state'']/value)[1]','int') AS State
  , xml_data.value('(/event/data[@name=''state_desc'']/value)[1]','sysname') AS State_desc
  , xml_data.query('(/event/data[@name="data"]/value/*)') AS Data
FROM 
(
      SELECT
                        object_name as event
                        ,CONVERT(xml, event_data) as xml_data
       FROM  
      sys.fn_xe_file_target_read_file('C:\Program Files\Microsoft SQL Server\MSSQL11.MSSQLSERVER\MSSQL\Log\*.xel', NULL, NULL, NULL)
) 
AS XEventData
ORDER BY time

The following example captures the output of sp_server_diagnostics to a table in a non-repeat mode:

CREATE TABLE SpServerDiagnosticsResult
(
      create_time DateTime,
      component_type sysname,
      component_name sysname,
      state int,
      state_desc sysname,
      data nvarchar(max)
)
INSERT INTO SpServerDiagnosticsResult 
EXEC sp_server_diagnostics

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