sp_server_diagnostics (Transact-SQL)
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.
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:
|
|
component_name |
Sysname |
Indicates the name of component or the name of the availability group:
|
|
state |
Int |
Indicates the health status of the component:
|
|
state_desc |
Sysname |
Describes the state column. Descriptions that correspond to the values in the state column are:
|
|
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").
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.
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