DMF sys.dm_exec_sql_text未显示DBID

Question

我有这个查询

http://technet.microsoft.com/en-us/library/ms181929.aspx

SELECT s2.dbid, 
    s1.sql_handle,  
    (SELECT TOP 1 SUBSTRING(s2.text,statement_start_offset / 2+1 , 
      ( (CASE WHEN statement_end_offset = -1 
         THEN (LEN(CONVERT(nvarchar(max),s2.text)) * 2) 
         ELSE statement_end_offset END)  - statement_start_offset) / 2+1))  AS sql_statement,
    execution_count, 
    plan_generation_num, 
    last_execution_time,   
    total_worker_time, 
    last_worker_time, 
    min_worker_time, 
    max_worker_time,
    total_physical_reads, 
    last_physical_reads, 
    min_physical_reads,  
    max_physical_reads,  
    total_logical_writes, 
    last_logical_writes, 
    min_logical_writes, 
    max_logical_writes  
FROM sys.dm_exec_query_stats AS s1 
CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS s2  
WHERE s2.objectid is null 
ORDER BY s1.sql_handle, s1.statement_start_offset, s1.statement_end_offset;

当我执行它时,dbid字段返回null. 为什么这样做？我想限制来自一个数据库的查询,但它似乎无法正常工作.

非常感谢你的回答.

Answer 1

1)SQL2005 - > SQL2008R2中提供了此行为.

2)为什么sys.dm_exec_sql_text.dbid(有时)有NULL？

• 在SQL2005中 - > SQL2008R2 dbid对于临时和准备好的SQL语句是"NULL"(请参阅SQL Server 2008 R2的 MSDN ).
• 在SQL 2012中"对于临时和准备好的SQL语句,编译语句的数据库的ID"(请参阅MSDN).因此,从SQL2012开始dbid将返回非NULL值,包括"ad hoc和准备好的SQL语句".

3)在SQL2008中解决这个问题 - >我使用的SQL2008R2 sys.dm_exec_plan_attributes(参见MSDN)

SELECT ..., ISNULL(s2.dbid,CONVERT(SMALLINT,att.value)) AS my_dbid, ...
FROM sys.dm_exec_query_stats AS s1 
CROSS APPLY sys.dm_exec_sql_text(sql_handle) AS s2 
CROSS APPLY sys.dm_exec_plan_attributes(s1.plan_handle) att
WHERE att.attribute='dbid