我有一个查询尝试查找某个边界框[地理编码查找]中的所有记录。为什么我的查询执行聚集索引扫描
通过RedGate探查器运行查询计划后,它在聚集索引扫描(下面)中花费了大量时间(问题底部的有问题的查询)。这是我运行速度最慢的查询,我猜这有什么问题,因为最后一步花了这么长时间?
有后环顾四周SO和谷歌,我决定,包括我的索引中的表的所有列。这里是我有什么指数
- PK上的Id。在[UTC_UPDATED说明,北,东,南,西]
- 指数[包括所有其他列尽量避免扫描]对[UTC_UPDATED说明,来源说明]
- 指数
查询:
SET ANSI_NULLS ON; SET ANSI_PADDING ON; SET ANSI_WARNINGS ON; SET ARITHABORT OFF; SET CONCAT_NULL_YIELDS_NULL ON; SET NUMERIC_ROUNDABORT OFF; SET QUOTED_IDENTIFIER ON
(@p__linq__0 datetime2(7),@p__linq__1 float,@p__linq__2 float,@p__linq__3 float,@p__linq__4 float)SELECT
[Project1].[ID] AS [ID],
[Project1].[CENTER] AS [CENTER],
[Project1].[BOUNDS] AS [BOUNDS],
[Project1].[UTC_UPDATED] AS [UTC_UPDATED],
[Project1].[PLACE_ID] AS [PLACE_ID],
[Project1].[FORMATTED_ADDRESS] AS [FORMATTED_ADDRESS],
[Project1].[POST_CODE] AS [POST_CODE],
[Project1].[SOURCE] AS [SOURCE],
[Project1].[North] AS [North],
[Project1].[East] AS [East],
[Project1].[South] AS [South],
[Project1].[West] AS [West]
FROM (SELECT
[Extent1].[ID] AS [ID],
[Extent1].[CENTER] AS [CENTER],
[Extent1].[BOUNDS] AS [BOUNDS],
[Extent1].[UTC_UPDATED] AS [UTC_UPDATED],
[Extent1].[PLACE_ID] AS [PLACE_ID],
[Extent1].[FORMATTED_ADDRESS] AS [FORMATTED_ADDRESS],
[Extent1].[POST_CODE] AS [POST_CODE],
[Extent1].[SOURCE] AS [SOURCE],
[Extent1].[North] AS [North],
[Extent1].[East] AS [East],
[Extent1].[South] AS [South],
[Extent1].[West] AS [West]
FROM [dbo].[HST_GEOCODE_POINTS] AS [Extent1]
WHERE ([Extent1].[UTC_UPDATED] > @p__linq__0)
AND ([Extent1].[North] >= @p__linq__1)
AND ([Extent1].[East] >= @p__linq__2)
AND ([Extent1].[South] <= @p__linq__3)
AND ([Extent1].[West] <= @p__linq__4)
) AS [Project1]
ORDER BY [Project1].[UTC_UPDATED] DESC, [Project1].[SOURCE] DESC
注边界和中心是地理类型。我最初使用Intersects来查找正确的Geocoded地址,但它非常慢,我选择使用SQL [它们只是双倍]来找到粗糙的NESW边界框,然后在代码[.NET]中相交。
在决定放弃SQL Server地理支持之前,您是否考虑/测试空间索引?鉴于大多数搜索谓词都是不等式,非聚集索引实际上是无用的。 –
从小处着手,重点关注您的搜索谓词(where子句)并返回您在内部Project 1表中过滤的列之一。确认它使用您的非聚集索引。添加额外的列可能会混淆优化器。 – user3112728
没有可以使用的索引。您的索引的前导列是UTC,并且在查询中没有UTC的条件。集群索引扫描是唯一可行的方法。 – sepupic