io-busy-transact-sql.md

title	@@IO_BUSY (Transact-SQL) | Microsoft Docs
ms.custom
ms.date	09/18/2017
ms.prod	sql
ms.prod_service	sql-database
ms.reviewer
ms.technology	t-sql
ms.topic	language-reference
f1_keywords	@@IO_BUSY @@IO_BUSY_TSQL
dev_langs	TSQL
helpviewer_keywords	ticks [SQL Server] I/O [SQL Server], time spent performing operations @@IO_BUSY function output operations [SQL Server] input operations [SQL Server] time [SQL Server], I/O operations
ms.assetid	3c26770c-41ae-4e34-8c82-7bef920ffbca
author	MikeRayMSFT
ms.author	mikeray

@@IO_BUSY (Transact-SQL)

[!INCLUDEtsql-appliesto-ss2008-xxxx-xxxx-xxx-md]

Returns the time that [!INCLUDEssNoVersion] has spent performing input and output operations since [!INCLUDEssNoVersion] was last started. The result is in CPU time increments ("ticks"), and is cumulative for all CPUs, so it may exceed the actual elapsed time. Multiply by @@TIMETICKS to convert to microseconds.

Note

If the time returned in @@CPU_BUSY, or @@IO_BUSY exceeds approximately 49 days of cumulative CPU time, you receive an arithmetic overflow warning. In that case, the value of @@CPU_BUSY, @@IO_BUSY and @@IDLE variables are not accurate.

Transact-SQL Syntax Conventions

Syntax

@@IO_BUSY  

Return Types

integer

Remarks

To display a report containing several [!INCLUDEssNoVersion] statistics, run sp_monitor.

Examples

The following example shows returning the number of milliseconds [!INCLUDEssNoVersion] has spent performing input/output operations between the start time and the current time. To avoid arithmetic overflow when converting the value to microseconds, the example converts one of the values to the float data type.

SELECT @@IO_BUSY*@@TIMETICKS AS 'IO microseconds',   
   GETDATE() AS 'as of';  

Here is a typical result set:

  
IO microseconds as of                   
--------------- ----------------------  
4552312500      12/5/2006 10:23:00 AM   

See Also

sys.dm_os_sys_info (Transact-SQL)
@@CPU_BUSY (Transact-SQL)
sp_monitor (Transact-SQL)
System Statistical Functions (Transact-SQL)