我有一个SQL查询,当我使用SQL Management Studio时,它只需要不到一秒钟就可以执行,但是当我的代码执行它时,从数据库服务器获取结果要花费30多秒的时间。查询结果包含1700行。另一个类似的查询,返回900行,只需要几毫秒的时间来执行。造成这种奇怪行为的原因是什么?
public SqlDataReader ExecuteReader(string strSQL, ArrayList arParams)
{
OpenConnection();
SqlCommand myCommand = new SqlCommand(strSQL, myConnection);
myCommand.CommandTimeout = intTimeout;
foreach (SqlParameter myParameter in arParams)
myCommand.Parameters.Add(myParameter);
return myCommand.ExecuteReader(System.Data.CommandBehavior.CloseConnection);
}
strSQL:
SELECT [Group].[Id]
,[Group].[intCustomerId]
,[Group].[strName]
,[Permission].[dtmCreated]
,[Permission].[intPermissionTypeId]
,[Permission].[intObjectTypeId]
,[Permission].[intObjectId]
,[Permission].[blnActive]
,[Permission].[blnHaveAccess]
,[Permission].[intLevelTypeId]
FROM [Group]
LEFT JOIN Permission ON [Group].[Id] = intGroupId AND
intObjectId = @ObjectId AND
intObjectTypeId = @ObjectTypeId AND
intLevelTypeId = @LevelType AND
intPermissionTypeId = @PermissionTypeId AND
blnActive = 1
WHERE [Group].[intCustomerId] = @CustomerId AND
[Group].[blnDeleted] = 0
ORDER BY strName, blnActive DESC
参数:
arParams.Add(DatabaseHandler.MakeSqlParameter("@CustomerId", customer.Id));
arParams.Add(DatabaseHandler.MakeSqlParameter("@ObjectId", masterprocess.Id));
arParams.Add(DatabaseHandler.MakeSqlParameter("@ObjectTypeId", Convert.ToInt32(ObjectType.MasterProcess)));
arParams.Add(DatabaseHandler.MakeSqlParameter("@PermissionTypeId", Convert.ToInt32(permissiontype)));
arParams.Add(DatabaseHandler.MakeSqlParameter("@LevelType", Convert.ToInt32(leveltype)));
DatabaseHandler.MakeSqlParameter:
public static SqlParameter MakeSqlParameter(String strName, int intInput)
{
return new SqlParameter(strName, intInput);
}
strSQL
是字面查询还是调用内部查询的某个存储过程的名称?您在两种情况下使用相同的参数值进行测试吗? - Christian.K