SQLSERVER2008中CTE的Split与CLR的性能比较

时间:2015-02-22 19:48 来源:linux.it.net.cn 作者:IT

我们新建一个DataBase project，然后建立一个UserDefinedFunctions,Code像这样:

	
	1: /// <summary> 

	/// SQLs the array. 

	/// </summary> 

	/// <param name="str">The STR.</param> 

	/// <param name="delimiter">The delimiter.</param> 

	/// <returns></returns> 

	/// 1/8/2010 2:41 PM author: v-pliu 

	[SqlFunction(Name = "CLR_Split", 

	FillRowMethodName = "FillRow", 

	TableDefinition = "id nvarchar(10)")] 

	public static IEnumerable SqlArray(SqlString str, SqlChars delimiter) 

	{ 

	if (delimiter.Length == 0) 

	return new string[1] { str.Value }; 

	return str.Value.Split(delimiter[0]); 

	} 

	/// <summary> 

	/// Fills the row. 

	/// </summary> 

	/// <param name="row">The row.</param> 

	/// <param name="str">The STR.</param> 

	/// 1/8/2010 2:41 PM author: v-pliu 

	public static void FillRow(object row, out SqlString str) 

	{ 

	str = new SqlString((string)row); 

	}

然后Bulid,Deploy一切OK后，在SSMS中执行以下测试T-sql:

	
	DECLARE @array VARCHAR(max) 

	SET @array = '39,15,93,68,64,43,90,58,39,9,26,26,89,47,91,57,98,16,55,9,63,29,69,16,41,76,34,60,68,64,61,53,32,30,11,72,57,63,36,43,22,14,60,38,24,5,66,26,26,21,22,99,55,18,7,10,46,76,27,88,9,29,89,75,48,72,94,59,35,19,0,35,79,11,87,49,68,30,91,35,9,7,34,47,41,61,98,13,22,1,26,80,35,48,34,92,24,85,90,51' SELECT id FROM dbo.CLR_Split(@array,',')

我们来看它的Client Statistic:

CLRSplit

接着我们执行测试T-sql使用相同的array:

	
	DECLARE @array VARCHAR(max) 

	SET @array = '39,15,93,68,64,43,90,58,39,9,26,26,89,47,91,57,98,16,55,9,63,29,69,16,41,76,34,60,68,64,61,53,32,30,11,72,57,63,36,43,22,14,60,38,24,5,66,26,26,21,22,99,55,18,7,10,46,76,27,88,9,29,89,75,48,72,94,59,35,19,0,35,79,11,87,49,68,30,91,35,9,7,34,47,41,61,98,13,22,1,26,80,35,48,34,92,24,85,90,51' 

	SELECT item FROM strToTable(@array,',')

CTE实现的Split function的Client statistic:

CTESplit

通过对比，你可以发现CLR的performance略高于CTE方式，原因在于CLR方式有Cache功能，并且把一个复杂的运算放到程序里比DataBase里更加高效。

(责任编辑：IT)