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编辑：我添加了登录触发器的所有代码。

为什么在尝试检索查询运行所需的总时间时会得到一些不正确的结果？这是在 SQL Server 2008 R2 上的登录触发器的上下文中。

出于测试目的，我想粗略估计运行登录触发器所需的总时间。这是结果的一个小样本：

LogonId  AppId  TotalLogonTime (in MS)
 101      1        0
 253      2        3
 289      2        3
 985      1       -3
 325      1        0

总时间如何评估为负数？在迄今为止的 230 万次执行中，有 25 次执行的时间为 -3 毫秒。这是代码：

CREATE trigger [trgAudit]
on all server
with execute as 'TriggerLogonUser'
for logon
as
begin
    set nocount on
    set transaction isolation level read committed

declare
     @LoginTime datetime
    ,@IsWindowsUser bit
    ,@TotalLogonTimeMS int
    ,@ClientNetAddress varchar(48)
    ,@MacAddress nchar(12)
    ,@CurrentUserId int -- UserNames
    ,@ApplicationId int
    ,@HonId int --HostName
    ,@LogonId int --Logon
    ,@MacId int -- MacAddress
    ,@CnaId int -- ClientNetAddress

begin try
    /*
    *** Get the login time, user type, mac address, and client net address  
    */
 select
      @LoginTime = getdate(),
      @IsWindowsUser = case
                          when len(nt_domain) = 0
                             then 0
                          else 1
                       end,
      @MacAddress = p.net_address,
      @ClientNetAddress = convert(varchar(48),connectionproperty('client_net_address'))
 from sys.sysprocesses p
 where 
      p.spid = @@spid

 /*
 *** Client Net Address
 */          
      select top 1
           @CnaId = CnaId
      from master.sysmaintenance.ClientNetAddress with(index(IX_CnaAddress))
      where @ClientNetAddress = CnaAddress

      --if the ip does not exist, insert it.
      if @CnaId is null
           begin
                insert master.sysmaintenance.ClientNetAddress(CnaAddress)
                     values (@ClientNetAddress)
                select @CnaId = @@identity
           end

 /*
 *** Applications
 */     
      select top 1
           @ApplicationId = AppId
      from master.sysmaintenance.Applications with(index(IX_AppName))
      where app_name() = AppName

      if @ApplicationId is null
           begin
                insert master.sysmaintenance.Applications (AppName)
                     values (app_name())
                select @ApplicationId = @@identity
           end

 /*
 *** HostName
 */     
      select top 1
           @HonId = HonId
      from master.sysmaintenance.HostName with(index(IX_HonName))
      where HonName = host_name()

      if @HonId is null
           begin
                insert master.sysmaintenance.HostName
                     values (host_name())

                select @HonId = @@identity
           end

 /*
 *** UserNames
 */     
      select top 1
           @CurrentUserId = UsnId
      from master.sysmaintenance.Usernames with(index(IX_UsnName))
      where UsnName = original_login()

      if @CurrentUserId is null
           begin
                insert master.sysmaintenance.Usernames
                     values (original_login())

                select @CurrentUserId = @@identity
           end

 /*
 *** MacAddress
 */     
      select top 1
           @MacId = MacId
      from master.sysmaintenance.MacAddress with(index(IX_MacAddress))
      where MacAddress = @MacAddress

      -- same logic is continued as in the applications
      if @MacId is null
           begin
                insert master.sysmaintenance.MacAddress (MacAddress)
                     values (@MacAddress)

                select @MacId = @@identity
           end

 /*
 *** Get the total logon time
 */     
 select @TotalLogonTimeMS = datediff(ms,@LoginTime, getdate())

  -- insert ids of the data gathered on the logon event into the logon table.


           insert master.sysmaintenance.Logon ( LogAppId,
                                                LogHonId,
                                                IsWindowsLogon,
                                                CurrentLogonId,
                                                LogonDatetime,
                                                LogCnaId,
                                                LogMacId,
                                                LogonTimeMS )
                values ( @ApplicationId,
                         @HonId,
                         @IsWindowsUser,
                         @CurrentUserId,
                         @LoginTime,
                         @CnaId,
                         @MacId,
                         @TotalLogonTimeMS
                       )
end try

begin catch
    print cast(error_number()    as nvarchar(11))
    print cast(error_severity()  as nvarchar(11))
    print cast(error_state()     as nvarchar(11))
    print cast(error_procedure() as nvarchar(126))
    print cast(error_line()      as nvarchar(11))
    print cast(error_message()   as nvarchar(2048))
end catch
end

这是登录表的 DDL：

CREATE TABLE [sysmaintenance].[Logon](
    [LogonId] [bigint] IDENTITY(1,1) NOT NULL,
    [LogAppId] [int] NULL,
    [LogHonId] [int] NULL,
    [LogMacId] [int] NULL,
    [LogCnaId] [int] NULL,
    [IsWindowsLogon] [bit] NULL,
    [CurrentLogonId] [int] NULL,
    [LogonDatetime] [datetime] NULL,
    [LogonTimeMS] [int] NULL
) ON [PRIMARY]

CREATE UNIQUE CLUSTERED INDEX [PK_Logon] ON [sysmaintenance].[Logon] 
(
    [LogonId] ASC
)WITH (PAD_INDEX  = OFF, STATISTICS_NORECOMPUTE  = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS  = ON, ALLOW_PAGE_LOCKS  = ON) ON [PRIMARY]

任何帮助或见解表示赞赏。

4

1 回答 1

1

GETDATE()：

将当前数据库系统时间戳作为日期时间值返回，不带数据库时区偏移量。此值源自运行 SQL Server 实例的计算机的操作系统。

现在，请记住计算机时钟会漂移，我想如果计算机的时间被纠正（手动或自动），两次连续调用GETDATE()（不是单个查询的一部分）报告的时间可能会倒退. 所有的 datetime 方法最终都依赖于计算机的时钟。

遗憾的是，您没有将其中一个GETDATE()结果与时间一起记录，因此您可以查看它们是否都在同一“时间”发生。

于 2013-01-31T14:33:23.840 回答