我想要了解Azure SQL數據倉庫中的分區表。但我看到的東西對我來說沒有意義。我顯然做錯了什麼,但我無法弄清楚它是什麼。Azure SQL數據倉庫表中的分區數據
我的意圖是用10000行數據填充第一個表(Marc.foo),檢查分區元數據,然後將分區切換到第二個空表(Marc.foo2)。
我開始通過創建兩個分區表:
IF OBJECT_ID('Marc.foo', 'U') IS NOT NULL
DROP TABLE Marc.foo
GO
IF OBJECT_ID('Marc.foo2', 'U') IS NOT NULL
DROP TABLE Marc.foo2
GO
CREATE TABLE Marc.foo
(
id int NOT NULL
)
WITH
(
DISTRIBUTION = HASH (id),
CLUSTERED COLUMNSTORE INDEX,
PARTITION (id RANGE RIGHT FOR VALUES (0, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000))
)
GO
CREATE TABLE Marc.foo2
(
id int NOT NULL
)
WITH
(
DISTRIBUTION = HASH (id),
CLUSTERED COLUMNSTORE INDEX,
PARTITION (id RANGE RIGHT FOR VALUES (0, 1000, 2000, 3000, 4000, 5000, 6000, 7000, 8000, 9000))
)
GO
我然後用10000行填充的第一個表(Marc.foo):
IF OBJECT_ID('tempdb..#numbers', 'U') IS NOT NULL
DROP TABLE #numbers
GO
WITH
CTE_2 AS (SELECT 1 as id UNION ALL SELECT 1 as id),
CTE_4 AS (SELECT a.id FROM CTE_2 a, CTE_2 b),
CTE_16 AS (SELECT a.id FROM CTE_4 a, CTE_4 b),
CTE_256 AS (SELECT a.id FROM CTE_16 a, CTE_16 b),
CTE_64K AS (SELECT a.id FROM CTE_256 a, CTE_256 b)
SELECT id
INTO #numbers
FROM CTE_64K
INSERT INTO Marc.foo(id)
SELECT ROW_NUMBER() OVER (ORDER BY (SELECT NULL)) FROM #numbers WHERE id <=10000
因爲我剛加載的數據到表,我打算在表格上創建統計數據:
CREATE STATISTICS stats_Marc_foo_id ON Marc.foo(id) WITH FULLSCAN
現在我檢查分區威剛:
SELECT sch.name AS [schema_name],
tbl.[name] AS [table_name],
ds.type_desc,
prt.[partition_number],
rng.[value] AS [current_partition_range_boundary_value],
prt.[rows] AS [partition_rows]
FROM sys.schemas sch
INNER JOIN sys.tables tbl ON sch.schema_id = tbl.schema_id
INNER JOIN sys.partitions prt ON prt.[object_id] = tbl.[object_id]
INNER JOIN sys.indexes idx ON prt.[object_id] = idx.[object_id] AND prt.[index_id] = idx.[index_id]
INNER JOIN sys.data_spaces ds ON idx.[data_space_id] = ds.[data_space_id]
INNER JOIN sys.partition_schemes ps ON ds.[data_space_id] = ps.[data_space_id]
INNER JOIN sys.partition_functions pf ON ps.[function_id] = pf.[function_id]
LEFT JOIN sys.partition_range_values rng ON pf.[function_id] = rng.[function_id] AND rng.[boundary_id] = prt.[partition_number]
WHERE sch.name = 'Marc' AND
tbl.name = 'foo'
問題1:這給了我什麼,我期待在current_partition_range_boundary_value方面,但partition_rows(我希望是1000)返回5957行的每個分區。
最後,我嘗試從Marc.foo SWITCH分區1至Marc.foo2
ALTER TABLE Marc.foo SWITCH PARTITION 1 to Marc.foo2 PARTITION 1
我希望,當我從Marc.foo2選擇,我應該可以看到1000行與ID值從1到1000但我回到零行。
問題2:我做錯了什麼?