# SQL Server Input Plugin

The `sqlserver` plugin provides metrics for your SQL Server instance. It
currently works with SQL Server 2008 SP3 and newer. Recorded metrics are
lightweight and use Dynamic Management Views supplied by SQL Server.

### Additional Setup:

You have to create a login on every instance you want to monitor, with following script:
```sql
USE master;
GO
CREATE LOGIN [telegraf] WITH PASSWORD = N'mystrongpassword';
GO
GRANT VIEW SERVER STATE TO [telegraf];
GO
GRANT VIEW ANY DEFINITION TO [telegraf];
GO
```

For Azure SQL Database, you require the View Database State permission and can create a user with a password directly in the database.
```sql
CREATE USER [telegraf] WITH PASSWORD = N'mystrongpassword';
GO
GRANT VIEW DATABASE STATE TO [telegraf];
GO
```

### Configuration:

```toml
[agent]
  ## Default data collection interval for all inputs, can be changed as per collection interval needs
  interval = "10s"

# Read metrics from Microsoft SQL Server
[[inputs.sqlserver]]
  ## Specify instances to monitor with a list of connection strings.
  ## All connection parameters are optional.
  ## By default, the host is localhost, listening on default port, TCP 1433.
  ##   for Windows, the user is the currently running AD user (SSO).
  ##   See https://github.com/denisenkom/go-mssqldb for detailed connection
  ##   parameters.
  # servers = [
  #  "Server=192.168.1.10;Port=1433;User Id=<user>;Password=<pw>;app name=telegraf;log=1;",
  # ]

  ## Optional parameter, setting this to 2 will use a new version
  ## of the collection queries that break compatibility with the original
  ## dashboards. All new functionality is under V2
  query_version = 2

  ## If you are using AzureDB, setting this to true will gather resource utilization metrics
  # azuredb = false

  ## If you would like to exclude some of the metrics queries, list them here
  ## Possible choices:
  ## - PerformanceCounters
  ## - WaitStatsCategorized
  ## - DatabaseIO
  ## - DatabaseProperties
  ## - CPUHistory
  ## - DatabaseSize
  ## - DatabaseStats
  ## - MemoryClerk
  ## - VolumeSpace
  ## - Schedulers
  ## - AzureDBResourceStats
  ## - AzureDBResourceGovernance 
  exclude_query = [ 'Schedulers' ]
```

### Metrics:
To provide backwards compatibility, this plugin support two versions of metrics queries.

**Note**: Version 2 queries are not backwards compatible with the old queries. Any dashboards or queries based on the old query format will not work with the new format. The version 2 queries are written in such a way as to only gather SQL specific metrics (no disk space or overall CPU related metrics) and they only report raw metrics, no math has been done to calculate deltas. To graph this data you must calculate deltas in your dashboarding software.

#### Version 1 (deprecated in 1.6):
The original metrics queries provide:
- *Performance counters*: 1000+ metrics from `sys.dm_os_performance_counters`
- *Performance metrics*: special performance and ratio metrics
- *Wait stats*: wait tasks categorized from `sys.dm_os_wait_stats`
- *Memory clerk*: memory breakdown from `sys.dm_os_memory_clerks`
- *Database size*: databases size trend from `sys.dm_io_virtual_file_stats`
- *Database IO*: databases I/O from `sys.dm_io_virtual_file_stats`
- *Database latency*: databases latency from `sys.dm_io_virtual_file_stats`
- *Database properties*: databases properties, state and recovery model, from `sys.databases`
- *OS Volume*: available, used and total space from `sys.dm_os_volume_stats`
- *CPU*: cpu usage from `sys.dm_os_ring_buffers`

If you are using the original queries all stats have the following tags:
- `servername`:  hostname:instance
- `type`: type of stats to easily filter measurements

#### Version 2:
The new (version 2) metrics provide:
- *Database IO*: IO stats from `sys.dm_io_virtual_file_stats`
- *Memory Clerk*: Memory clerk breakdown from `sys.dm_os_memory_clerks`, most clerks have been given a friendly name.
- *Performance Counters*: A select list of performance counters from `sys.dm_os_performance_counters`. Some of the important metrics included:
  - *Activity*: Transactions/sec/database, Batch requests/sec, blocked processes, + more
  - *Availability Groups*: Bytes sent to replica, Bytes received from replica, Log bytes received, Log send queue, transaction delay, + more
  - *Log activity*: Log bytes flushed/sec, Log flushes/sec, Log Flush Wait Time
  - *Memory*: PLE, Page reads/sec, Page writes/sec, + more
  - *TempDB*: Free space, Version store usage, Active temp tables, temp table creation rate, + more
  - *Resource Governor*: CPU Usage, Requests/sec, Queued Requests, and Blocked tasks per workload group + more
- *Server properties*: Number of databases in all possible states (online, offline, suspect, etc.), cpu count, physical memory, SQL Server service uptime, and SQL Server version. In the case of Azure SQL relevent properties such as Tier, #Vcores, Memory etc.
- *Wait stats*: Wait time in ms, number of waiting tasks, resource wait time, signal wait time, max wait time in ms, wait type, and wait category. The waits are categorized using the same categories used in Query Store.
- *Schedulers* - This captures sys.dm_os_schedulers.
- *Azure Managed Instances*
  - Stats from `sys.server_resource_stats`:
    - cpu_count
    - server_memory
    - sku
    - engine_edition
    - hardware_type
    - total_storage_mb
    - available_storage_mb
    - uptime
  - Resource governance stats from sys.dm_instance_resource_governance
- *Azure SQL Database*
  - Stats from sys.dm_db_wait_stats
  - Resource governance stats from sys.dm_user_db_resource_governance
  - Stats from sys.dm_db_resource_stats

The following metrics can be used directly, with no delta calculations:
 - SQLServer:Buffer Manager\Buffer cache hit ratio
 - SQLServer:Buffer Manager\Page life expectancy
 - SQLServer:Buffer Node\Page life expectancy
 - SQLServer:Database Replica\Log Apply Pending Queue
 - SQLServer:Database Replica\Log Apply Ready Queue
 - SQLServer:Database Replica\Log Send Queue
 - SQLServer:Database Replica\Recovery Queue
 - SQLServer:Databases\Data File(s) Size (KB)
 - SQLServer:Databases\Log File(s) Size (KB)
 - SQLServer:Databases\Log File(s) Used Size (KB)
 - SQLServer:Databases\XTP Memory Used (KB)
 - SQLServer:General Statistics\Active Temp Tables
 - SQLServer:General Statistics\Processes blocked
 - SQLServer:General Statistics\Temp Tables For Destruction
 - SQLServer:General Statistics\User Connections
 - SQLServer:Memory Broker Clerks\Memory broker clerk size
 - SQLServer:Memory Manager\Memory Grants Pending
 - SQLServer:Memory Manager\Target Server Memory (KB)
 - SQLServer:Memory Manager\Total Server Memory (KB)
 - SQLServer:Resource Pool Stats\Active memory grant amount (KB)
 - SQLServer:Resource Pool Stats\Disk Read Bytes/sec
 - SQLServer:Resource Pool Stats\Disk Read IO Throttled/sec
 - SQLServer:Resource Pool Stats\Disk Read IO/sec
 - SQLServer:Resource Pool Stats\Disk Write Bytes/sec
 - SQLServer:Resource Pool Stats\Disk Write IO Throttled/sec
 - SQLServer:Resource Pool Stats\Disk Write IO/sec
 - SQLServer:Resource Pool Stats\Used memory (KB)
 - SQLServer:Transactions\Free Space in tempdb (KB)
 - SQLServer:Transactions\Version Store Size (KB)
 - SQLServer:User Settable\Query
 - SQLServer:Workload Group Stats\Blocked tasks
 - SQLServer:Workload Group Stats\CPU usage %
 - SQLServer:Workload Group Stats\Queued requests
 - SQLServer:Workload Group Stats\Requests completed/sec

Version 2 queries have the following tags:
- `sql_instance`: Physical host and instance name (hostname:instance)
- database_name:  For Azure SQLDB, database_name denotes the name of the Azure SQL Database as server name is a logical construct.
