触发失败时发送电子邮件答案

【问题标题】：Send email on trigger failure触发失败时发送电子邮件
【发布时间】：2012-08-14 09:41:05
【问题描述】：

我已成功配置并能够通过调用 msdb.dbo.sp_send_dbmail 存储过程在 SQL Server 2008 R2 上使用“数据库邮件”发送电子邮件。我可以通过将它放在 try-catch 块中来捕获触发器中的查询失败。

但我需要做的是，当触发器无法执行查询时发送电子邮件。但是我不能在 catch 块中执行上面的存储过程。它给了我以下错误。

Msg 3930, Level 16, State 1, Procedure sp_send_dbmail, Line 64
The current transaction cannot be committed and cannot support operations that write to the log file. Roll back the transaction.
The statement has been terminated.

还有其他方法可以在触发失败时发送电子邮件吗？或者如何解决这个问题？

【问题讨论】：

标签： sql sql-server email triggers django-mssql

【解决方案1】：

触发器失败总是会导致事务回滚，因此它不能执行任何事务操作，例如调用sp_send_dbmail。一个技巧是利用自定义分析器跟踪事件，因为它们是在独立事务中发送的：

create queue q;
create service sq 
    on queue q
    ([http://schemas.microsoft.com/SQL/Notifications/PostEventNotification]);
go

create event notification trace_user_0
    on server 
    for TRC_USER_CONFIGURABLE
    to service N'sq', N'current database';
go


create procedure usp_sq
as
begin

    declare @dh uniqueidentifier, 
        @mt sysname, 
        @mb varbinary(max),
        @mx xml;

    begin transaction

    receive top(1) 
        @dh = conversation_handle,
        @mt = message_type_name,
        @mb = message_body
        from q;

    if @mt = N'http://schemas.microsoft.com/SQL/Notifications/EventNotification'
    begin
        set @mx = cast(@mb as xml);

        declare @eventText nvarchar(4000);
        select @eventText = @mx.value (N'(//EVENT_INSTANCE/TextData)[1]', N'nvarchar(4000)');

        exec sp_send_dbmail @subject = 'Error in trigger', @body = @eventText;

    end
    else if @mt in (
        N'http://schemas.microsoft.com/SQL/ServiceBroker/Error', 
        N'http://schemas.microsoft.com/SQL/ServiceBroker/EndDialog')
    begin
        end conversation @dh;
    end

    commit

end
go

alter queue q with activation (
    status = on,
    max_queue_readers = 1,
    execute as = 'owner',
    procedure_name = 'usp_sq');
go

create table MyTable (a int);
go

create trigger MyTrigger 
    on MyTable 
    after insert
as
begin try
    if rand() > 0.5
        raiserror (N'Something horrible happend in this trigger!', 16,1);
end try
begin catch
    declare @error_message nvarchar(256) = cast(error_message() as nvarchar(256));
    exec sp_trace_generateevent 82, @error_message;
end catch
go

insert into MyTable (a) values (1);
insert into MyTable (a) values (2);
insert into MyTable (a) values (3);
insert into MyTable (a) values (4);
insert into MyTable (a) values (5);
insert into MyTable (a) values (6);
go

【讨论】：