出于某种原因，我发现使用此查询的时间间隔存在差距。我只是在使用基本数据时才能使用它。但是，在连接我的表并指定WHERE子句时，我会在时间间隔中看到间隙。我还需要在我的间隔中加入S.SessionEndTime来查找与ResponseTime和SessionEndTime之间给定的1分钟间隔重叠的记录计数。
这是我正在使用的查询。通过使用派生表，我每小时根据COUNT获得一个MAX，间隔为1分钟。
答案 0 :(得分：0)
好的，这里缺乏澄清是一些计算两者的TSQL： - 每小时活跃的会话总数和 - 每小时活动的最大并发会话数。
编辑：已使用来自更新问题的示例数据，显示并发会话的最后一个查询的输出现在包括会话ID，并且先前优化中的错误已更正< em>非常提高了性能。
NB ：当SessionId值因行而异时，这些查询效果最佳。对所有行使用值1将导致令人失望的结果。因此，IDENTITY列上的SessionId属性。
-- Parameters.
declare @Start as DateTime = '20120901 00:00:00'
declare @End as DateTime = '20120901 12:00:00'
declare @Interval as Time = '01:00:00.00' -- One hour.
select @Start as [Start], @End as [End], @Interval as [Interval]
-- Sample data.
declare @Sessions as Table ( SessionId Int Identity, SessionStart DateTime, SessionEnd DateTime )
insert into @Sessions ( SessionStart, SessionEnd ) values
( '20120901 00:00:00', '20120901 05:59:59' ), -- Several hours in a single session.
( '20120901 01:01:00', '20120901 01:01:30' ), -- An assortment of overlapping ...
( '20120901 01:02:00', '20120901 01:03:30' ), -- ... sessions during a single hour.
( '20120901 00:00:05.077', '20120901 00:04:02.280' ),
( '20120901 00:00:14.687', '20120901 00:06:05.947' ),
( '20120901 00:00:17.857', '20120901 00:07:34.757' ),
( '20120901 00:00:25.843', '20120901 00:07:38.720' ),
( '20120901 00:00:29.427', '20120901 00:01:58.180' ),
( '20120901 00:00:31.853', '20120901 00:05:10.733' ),
( '20120901 00:00:40.693', '20120901 00:00:44.237' ),
( '20120901 00:00:58.773', '20120901 00:06:14.667' ),
( '20120901 00:00:59.457', '20120901 00:01:01.310' ),
( '20120901 00:01:16.390', '20120901 00:11:18.383' )
select * from @Sessions
-- Summary of sessions active at any time during each hour.
; with SampleWindows as (
select @Start as WindowStart, @Start + @Interval as WindowEnd
union all
select SW.WindowStart + @Interval, SW.WindowEnd + @Interval
from SampleWindows as SW
where SW.WindowEnd < @End
)
select SW.WindowStart, Count( S.SessionStart ) as [Sessions]
from SampleWindows as SW left outer join
@Sessions as S on SW.WindowStart <= S.SessionEnd and S.SessionStart < SW.WindowEnd
group by SW.WindowStart
-- Summary of maximum concurrent sessions active during each hour.
; with SampleWindows as (
select 1 as SampleWindowId, @Start as WindowStart, @Start + @Interval as WindowEnd
union all
select SW.SampleWindowId + 1, SW.WindowStart + @Interval, SW.WindowEnd + @Interval
from SampleWindows as SW
where SW.WindowEnd < @End
),
ActiveSessionsDuringWindow as (
select SW.SampleWindowId, SW.WindowStart, SW.WindowEnd, S.SessionId, S.SessionStart, S.SessionEnd,
-- A "pane" is the more restrictive of the window and the session start/end times.
case when SW.WindowStart <= S.SessionStart then S.SessionStart else SW.WindowStart end as PaneStart,
case when SW.WindowEnd >= S.SessionEnd then S.SessionEnd else SW.WindowEnd end as PaneEnd
from SampleWindows as SW left outer join
@Sessions as S on SW.WindowStart <= S.SessionEnd and S.SessionStart < SW.WindowEnd
),
ConcurrentSearch as (
select SampleWindowId, WindowStart, WindowEnd, SessionId, SessionStart, SessionEnd, PaneStart, PaneEnd,
Cast( '|' + Right( Replicate( '0', 3 ) + Cast( SessionId as VarChar(4) ), 4 ) + '|' as VarChar(1024) ) as SessionIds,
Cast( case when SessionId is NULL then 0 else 1 end as Int ) as Sessions
from ActiveSessionsDuringWindow
union all
select CS.SampleWindowId, CS.WindowStart, CS.WindowEnd, ASDW.SessionId, CS.SessionStart, CS.SessionEnd,
case when CS.PaneStart <= ASDW.PaneStart then ASDW.PaneStart else CS.PaneStart end as PaneStart,
case when CS.PaneEnd >= ASDW.PaneEnd then ASDW.PaneEnd else CS.PaneEnd end as PaneEnd,
Cast( CS.SessionIds + Right( Replicate( '0', 3 ) + Cast( ASDW.SessionId as VarChar(4) ), 4 ) + '|' as VarChar(1024) ),
CS.Sessions + 1
from ConcurrentSearch as CS inner join
ActiveSessionsDuringWindow as ASDW on ASDW.SampleWindowId = CS.SampleWindowId and
-- We haven't visited this session along this path.
CS.SessionId < ASDW.SessionId and -- EDIT: Reduce the size of the search tree.
CharIndex( '|' + Right( Replicate( '0', 3 ) + Cast( ASDW.SessionId as VarChar(4) ), 4 ) + '|', CS.SessionIds ) = 0 and
-- The session's pane overlaps the concurrent search pane.
CS.PaneStart <= ASDW.PaneEnd and ASDW.PaneStart <= CS.PaneEnd
)
select WindowStart, Max( Sessions ) as Sessions,
( select top 1 SessionIds from ConcurrentSearch where Sessions = Max( CS.Sessions ) ) as SessionIds
from ConcurrentSearch as CS
group by WindowStart
以下是最后一个查询的变体，它不使用@Sessions表中的行ID值。相反，它使用Row_Number()为查询的持续时间分配合适的值。这也改变了SessionId值不超过四位的假设，假设在任何给定的小时内活动不超过9,999个。
-- Summary of maximum concurrent sessions active during each hour.
; with SampleWindows as (
select 1 as SampleWindowId, @Start as WindowStart, @Start + @Interval as WindowEnd
union all
select SW.SampleWindowId + 1, SW.WindowStart + @Interval, SW.WindowEnd + @Interval
from SampleWindows as SW
where SW.WindowEnd < @End
),
ActiveSessionsDuringWindow as (
select SW.SampleWindowId, SW.WindowStart, SW.WindowEnd, S.SessionStart, S.SessionEnd,
-- A "pane" is the more restrictive of the window and the session start/end times.
case when SW.WindowStart <= S.SessionStart then S.SessionStart else SW.WindowStart end as PaneStart,
case when SW.WindowEnd >= S.SessionEnd then S.SessionEnd else SW.WindowEnd end as PaneEnd,
Row_Number() over ( partition by SW.SampleWindowId order by S.SessionStart ) as SampleId
from SampleWindows as SW left outer join
@Sessions as S on SW.WindowStart <= S.SessionEnd and S.SessionStart < SW.WindowEnd
),
ConcurrentSearch as (
select SampleWindowId, WindowStart, WindowEnd, SampleId, SessionStart, SessionEnd, PaneStart, PaneEnd,
Cast( '|' + Right( Replicate( '0', 3 ) + Cast( SampleId as VarChar(4) ), 4 ) + '|' as VarChar(1024) ) as SampleIds,
Cast( case when SampleId is NULL then 0 else 1 end as Int ) as Sessions
from ActiveSessionsDuringWindow
union all
select CS.SampleWindowId, CS.WindowStart, CS.WindowEnd, ASDW.SampleId, CS.SessionStart, CS.SessionEnd,
case when CS.PaneStart <= ASDW.PaneStart then ASDW.PaneStart else CS.PaneStart end as PaneStart,
case when CS.PaneEnd >= ASDW.PaneEnd then ASDW.PaneEnd else CS.PaneEnd end as PaneEnd,
Cast( CS.SampleIds + Right( Replicate( '0', 3 ) + Cast( ASDW.SampleId as VarChar(4) ), 4 ) + '|' as VarChar(1024) ),
CS.Sessions + 1
from ConcurrentSearch as CS inner join
ActiveSessionsDuringWindow as ASDW on ASDW.SampleWindowId = CS.SampleWindowId and
-- We haven't visited this session along this path.
CS.SampleId < ASDW.SampleId and -- EDIT: Reduce the size of the search tree.
CharIndex( '|' + Right( Replicate( '0', 3 ) + Cast( ASDW.SampleId as VarChar(4) ), 4 ) + '|', CS.SampleIds ) = 0 and
-- The session's pane overlaps the concurrent search pane.
CS.PaneStart <= ASDW.PaneEnd and ASDW.PaneStart <= CS.PaneEnd
)
select WindowStart, Max( Sessions ) as Sessions
from ConcurrentSearch as CS
group by WindowStart
这应该很容易修改以针对现有表运行。 SessionStart升序，SessionEnd升序的单个索引应该可以提高效果。