外部連接兩個表與連續指導檔位

Question

我正試圖對兩個不相關的表執行完整的外部連接。每個表都有一個location_id，最終形成主鍵/外鍵關係（一旦我找出這個性能問題）。當執行外部連接時，它只是消失。在不到一秒的時間內，對每個表執行查詢和觸發器。

此表有21000個記錄：

CREATE TABLE [dbo].[TBL_LOCATIONS](
    [OBJECTID] [int] NOT NULL, 
    [Loc_Name] [nvarchar](100) NULL, 
    [Location_ID] [uniqueidentifier] NULL, 
    [SHAPE] [geometry] NULL, 

CONSTRAINT [R33_pk] PRIMARY KEY CLUSTERED 
(
    [OBJECTID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 75) ON [PRIMARY] 
) ON [PRIMARY] 
GO 
ALTER TABLE [dbo].[TBL_LOCATIONS] WITH CHECK ADD CONSTRAINT [g17_ck] CHECK (([SHAPE].[STSrid]=(26917))) 
GO 
ALTER TABLE [dbo].[TBL_LOCATIONS] ADD CONSTRAINT [DF_TBL_LOCATIONS_Location_ID] DEFAULT (newsequentialid()) FOR [Location_ID] 
GO 

CREATE SPATIAL INDEX [S17_idx] ON [dbo].[TBL_LOCATIONS] 
(
    [SHAPE] 
)USING GEOMETRY_GRID 
WITH (
BOUNDING_BOX =(224827, 3923750, 323464, 3967780), GRIDS =(LEVEL_1 = HIGH,LEVEL_2 = HIGH,LEVEL_3 = HIGH,LEVEL_4 = HIGH), 
CELLS_PER_OBJECT = 16, PAD_INDEX = OFF, SORT_IN_TEMPDB = OFF, DROP_EXISTING = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
GO 

CREATE UNIQUE NONCLUSTERED INDEX [UUID_OID_33] ON [dbo].[TBL_LOCATIONS] 
(
    [Location_ID] ASC, 
    [OBJECTID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 75) ON [PRIMARY] 
GO 

這個表有53000條記錄

CREATE TABLE [dbo].[TBL_EVENTS](
    [OBJECTID] [int] NOT NULL, 
    [Event_ID] [uniqueidentifier] NULL, 
    [Location_ID] [uniqueidentifier] NULL, 
CONSTRAINT [PK_TBL_EVENTS] PRIMARY KEY CLUSTERED 
(
    [OBJECTID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, IGNORE_DUP_KEY = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON) ON [PRIMARY] 
) ON [PRIMARY] 
GO 
ALTER TABLE [dbo].[TBL_EVENTS] ADD CONSTRAINT [DF_TBL_EVENTS_Event_ID] DEFAULT (newsequentialid()) FOR [Event_ID] 
GO 
ALTER TABLE [dbo].[TBL_EVENTS] ADD CONSTRAINT [DF_TBL_EVENTS_Event_ID] DEFAULT (newsequentialid()) FOR [Event_ID] 
GO 

CREATE UNIQUE NONCLUSTERED INDEX [R36_SDE_ROWID_UK] ON [dbo].[TBL_EVENTS] 
(
    [OBJECTID] ASC 
)WITH (PAD_INDEX = OFF, STATISTICS_NORECOMPUTE = OFF, SORT_IN_TEMPDB = OFF, IGNORE_DUP_KEY = OFF, DROP_EXISTING = OFF, ONLINE = OFF, ALLOW_ROW_LOCKS = ON, ALLOW_PAGE_LOCKS = ON, FILLFACTOR = 75) ON [PRIMARY] 
GO 

這裏是正在運行....和運行查詢...... 1小時，無結果。

SELECT  
    TBL_LOCATIONS.Loc_Name, 
    TBL_LOCATIONS.Location_ID, 
    TBL_LOCATIONS.SHAPE, 
    TBL_EVENTS.Event_ID 
FROM   
    TBL_EVENTS 
FULL OUTER JOIN 
    TBL_LOCATIONS ON TBL_EVENTS.Location_ID = TBL_LOCATIONS.Location_ID 

我試過屬性索引的每一個排列在兩個表，重建和重組他們，沒有什麼會影響性能。應用程序要求使用ObjectID作爲PK，與sequ​​entialGUID一樣。我不認爲這些都是因素，因爲這些表格在這個查詢之外都表現出色。 SQL Server 2008 SP1 64位RAID 10/48 GB RAM。

Answer 1

FULL JOIN當用於鏈接表的列中的數據是唯一的時候工作良好。

對於行包含重複數據FULL JOIN行爲就像CROSS JOIN，並可能導致服務表現的問題。

因此可能的瓶頸來自LOCATION_ID列中的重複項。

Answer 2

如果鏈接字段值不是全部唯一（位置），則查詢大小可能會接近相當大的數量。

在一個極端的例子中，如果兩個表中的位置只有值「1」，那麼總行數將接近交叉連接大小，大約爲1,113,000,000行（21,000 * 53,000）。這個大小（超過10億行）的查詢將需要很長時間才能運行。

編輯 - 更新不正確的語句在評論

Answer 3

指出，也許你需要考慮關閉事務日誌記錄，同時做了這一切。