T-SQL较差的CTE连接性能
长话短说。我有两个非常相似的SQL查询,它们输出短名称和长名称的值对。输入参数用于第一个查询:短名称,第二个查询为长名称。构造的查询输出包含输入参数的所有行,但这不完全匹配(例如,如果我将标记名设置为ST2,则此查询输出包含ST2的所有对象以及名称开头包含ST2的所有其他对象) 所有查询都在同一数据库中执行。在下面的查询中,输入参数设置为T-SQL较差的CTE连接性能,sql,sql-server,common-table-expression,Sql,Sql Server,Common Table Expression,长话短说。我有两个非常相似的SQL查询,它们输出短名称和长名称的值对。输入参数用于第一个查询:短名称,第二个查询为长名称。构造的查询输出包含输入参数的所有行,但这不完全匹配(例如,如果我将标记名设置为ST2,则此查询输出包含ST2的所有对象以及名称开头包含ST2的所有其他对象) 所有查询都在同一数据库中执行。在下面的查询中,输入参数设置为”,这意味着查询输出所有对象的短名称和长名称的键值对 declare @tagName as varchar(50) = '' set @tagName = @
”
,这意味着查询输出所有对象的短名称和长名称的键值对
declare @tagName as varchar(50) = ''
set @tagName = @tagName + '.'
-- this one query outputs ~700 rows
;with AnalogTag as
(
Select *
from [Runtime].[dbo].[AnalogTag]
where (substring(TagName, 0, charindex('.',@tagName))) in (substring(@tagName,0, len(@tagName)))
and (substring(TagName, charindex('.',TagName), 2)) not in ('.#')
),
-- this one query outputs ~7000 rows
HierarchicalName as
(
Select *
from [proba7].[dbo].[internal_list_objects_view]
where substring(tag_name, 0,len(@tagName)) = substring(@tagName,0, len(@tagName))
)
select HierarchicalName.tag_name as TagName
,HierarchicalName.hierarchical_name ilo_view_HierarchicalName
from AnalogTag
inner join HierarchicalName
on substring(AnalogTag.TagName, 0, CHARINDEX('.',AnalogTag.TagName)) = HierarchicalName.tag_name
上面的整个查询运行大约3秒,并输出大约450行
我在同一个数据库上创建了一个类似的查询:
declare @hierarchicalName as varchar(200) = ''
declare @Length as int
set @Length = LEN(@hierarchicalName)+1
-- this query outputs approx 700 rows and if runs separately it runs
--almost instantly
;with AnalogTag as
(
Select TagName
from [Runtime].[dbo].[AnalogTag]
where (substring(TagName, 0, CHARINDEX('.',TagName))) in
(
Select tag_name from [proba7].[dbo].[internal_list_objects_view]
where substring(hierarchical_name, 0, @Length) = @hierarchicalName
)
and (substring(TagName, CHARINDEX('.',TagName), 2)) not in ('.#')
),
-- this query outputs approx 7000 rows and if runs separately it runs
--almost instantly
HierarchicalName as
(
Select hierarchical_name, tag_name from [proba7].[dbo].[internal_list_objects_view]
where substring(hierarchical_name, 0, @Length) = @hierarchicalName
)
select HierarchicalName.tag_name as ilo_view_TagName
,HierarchicalName.hierarchical_name ilo_view_HierarchicalName
from AnalogTag
inner join HierarchicalName
on substring(AnalogTag.TagName, 0, CHARINDEX('.',AnalogTag.TagName)) = HierarchicalName.tag_name
这次查询在28秒内运行。输出的行数与第一次查询的行数相似(因为在这两次查询中,ouptut必须相似)。我注意到,如果我将“内部联接”更改为例如“完全联接”,查询将立即运行
模拟标签示例输出:
TagName a b c d e f g h j j k l m
PomFPTemp.PV 1062 0 10 0 10 0 4 0 0 0 0 0 0
PomFPWilgWzgl.PV 1 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocD3f.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocP3f.PV 46 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocQ3f.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocQ3fIntExp.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocQ3fIntImp.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocQn3f.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1EnkvarhExp3f.PV 1060 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1EnkvarhImp3f.PV 1060 0 10 0 10 0 4 0 0 0 0 0 0
ID tag_name contained_name hierarchical_name a b c d e f g h i j k l m n o p q r s t u v w x y z aa bb cc dd ee ff gg hh
1 $Galaxy $Galaxy 1 0 0 0 0 1 NULL NULL 0 0 1 1 1 0 0 0 0 0 1 0 NULL 23 0 0 0 0 0 0 0 0 0 133123 50026 1 NULL
2 proba7 Galaxy_001 0 0 0 0 1 1 NULL NULL 0 0 848 1 0 1 0 0 0 0 1 0 NULL 23 0 0 0 0 0 0 0 0 0 4098 878020 1 NULL
3 $_AutoImport $_AutoImport 1 0 0 0 0 3 NULL NULL 0 0 4 2 0 0 0 0 0 0 1 0 NULL 10 0 0 0 0 0 0 0 0 0 131075 3699 1 NULL
4 $_DiCommon $_DiCommon 1 0 0 0 0 4 NULL NULL 0 0 5 3 0 0 0 0 0 0 1 0 NULL 10 0 0 0 0 0 0 0 0 0 131075 50023 1 NULL
5 $WinPlatform $WinPlatform 1 0 0 0 0 5 NULL 1 0 0 6 4 1 0 0 0 0 0 0 0 NULL 1 0 0 0 0 0 0 0 0 0 133121 419340 1 1
6 $AppEngine $AppEngine 1 0 0 0 0 6 NULL 1 0 0 7 5 1 0 0 0 0 0 0 0 NULL 3 0 0 0 0 0 0 0 0 0 133121 419341 1 1
7 $Area $Area 1 0 0 0 0 7 NULL 1 0 0 8 6 1 0 0 0 0 0 0 0 NULL 13 0 0 0 0 0 0 0 0 0 133121 3452998 1 1
8 $AnalogDevice $AnalogDevice 1 0 0 0 0 8 NULL 2 0 0 9 7 0 0 0 0 0 0 0 0 NULL 10 0 0 0 0 0 0 0 0 0 131073 419343 1 2
9 $DDESuiteLinkClient $DDESuiteLinkClient 1 0 0 0 0 9 NULL 3 0 0 10 8 1 0 0 0 0 0 0 0 NULL 11 0 0 0 0 0 0 0 0 0 133121 419344 1 3
10 $DiscreteDevice $DiscreteDevice 1 0 0 0 0 10 NULL 2 0 0 11 9 0 0 0 0 0 0 0 0 NULL 10 0 0 0 0 0 0 0 0 0 131073 419345 1 2
11 $InTouchProxy $InTouchProxy 1 0 0 0 0 11 NULL 3 0 0 12 10 0 0 0 0 0 0 0 0 NULL 11 0 0 0 0 0 0 0 0 0 131073 419346 1 3
分层名称示例输出:
TagName a b c d e f g h j j k l m
PomFPTemp.PV 1062 0 10 0 10 0 4 0 0 0 0 0 0
PomFPWilgWzgl.PV 1 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocD3f.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocP3f.PV 46 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocQ3f.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocQ3fIntExp.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocQ3fIntImp.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1BrakFWHMocQn3f.PV 1063 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1EnkvarhExp3f.PV 1060 0 10 0 10 0 4 0 0 0 0 0 0
SNST3P1EnkvarhImp3f.PV 1060 0 10 0 10 0 4 0 0 0 0 0 0
ID tag_name contained_name hierarchical_name a b c d e f g h i j k l m n o p q r s t u v w x y z aa bb cc dd ee ff gg hh
1 $Galaxy $Galaxy 1 0 0 0 0 1 NULL NULL 0 0 1 1 1 0 0 0 0 0 1 0 NULL 23 0 0 0 0 0 0 0 0 0 133123 50026 1 NULL
2 proba7 Galaxy_001 0 0 0 0 1 1 NULL NULL 0 0 848 1 0 1 0 0 0 0 1 0 NULL 23 0 0 0 0 0 0 0 0 0 4098 878020 1 NULL
3 $_AutoImport $_AutoImport 1 0 0 0 0 3 NULL NULL 0 0 4 2 0 0 0 0 0 0 1 0 NULL 10 0 0 0 0 0 0 0 0 0 131075 3699 1 NULL
4 $_DiCommon $_DiCommon 1 0 0 0 0 4 NULL NULL 0 0 5 3 0 0 0 0 0 0 1 0 NULL 10 0 0 0 0 0 0 0 0 0 131075 50023 1 NULL
5 $WinPlatform $WinPlatform 1 0 0 0 0 5 NULL 1 0 0 6 4 1 0 0 0 0 0 0 0 NULL 1 0 0 0 0 0 0 0 0 0 133121 419340 1 1
6 $AppEngine $AppEngine 1 0 0 0 0 6 NULL 1 0 0 7 5 1 0 0 0 0 0 0 0 NULL 3 0 0 0 0 0 0 0 0 0 133121 419341 1 1
7 $Area $Area 1 0 0 0 0 7 NULL 1 0 0 8 6 1 0 0 0 0 0 0 0 NULL 13 0 0 0 0 0 0 0 0 0 133121 3452998 1 1
8 $AnalogDevice $AnalogDevice 1 0 0 0 0 8 NULL 2 0 0 9 7 0 0 0 0 0 0 0 0 NULL 10 0 0 0 0 0 0 0 0 0 131073 419343 1 2
9 $DDESuiteLinkClient $DDESuiteLinkClient 1 0 0 0 0 9 NULL 3 0 0 10 8 1 0 0 0 0 0 0 0 NULL 11 0 0 0 0 0 0 0 0 0 133121 419344 1 3
10 $DiscreteDevice $DiscreteDevice 1 0 0 0 0 10 NULL 2 0 0 11 9 0 0 0 0 0 0 0 0 NULL 10 0 0 0 0 0 0 0 0 0 131073 419345 1 2
11 $InTouchProxy $InTouchProxy 1 0 0 0 0 11 NULL 3 0 0 12 10 0 0 0 0 0 0 0 0 NULL 11 0 0 0 0 0 0 0 0 0 131073 419346 1 3
输出表(示例):
向您致意并提前感谢您的建议。我尽了最大努力使此示例表可读。这应该是索引问题。在启用查询执行计划的情况下运行两个查询,我相信您会发现每个查询都使用了不同的索引。不过,我建议在SELECT而不是WHERE子句下使用substring()(例如,可以使用子查询)。删除连接条件中的子字符串将使其速度更快。因此,如果可以使数据“漂亮”,这将是对子字符串()的另一种方法部分,如果它是一个固定状态,这意味着它将被反复使用,您可以使用computed column,这将优化您的表和查询。从查询执行计划中,我可以看到大多数成本是以25%的成本在聚集索引扫描中。每种成本为7%的哈希匹配很少。在CTE INST中使用select substring时没有区别在内部联接子句中选择子字符串的ad