我想要了解Azure SQL数据仓库中的分区表。但我看到的东西对我来说没有意义。我显然做错了什么,但我无法弄清楚它是什么。Azure SQL数据仓库表中的分区数据
我的意图是用10000行数据填充第一个表(Marc.foo),检查分区元数据,然后将分区切换到第二个空表(Marc.foo2)。
我开始通过创建两个分区表:
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
我然后用10000行填充的第一个表(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
因为我刚加载的数据到表,我打算在表格上创建统计数据:
CREATE STATISTICS stats_Marc_foo_id ON Marc.foo(id) WITH FULLSCAN
现在我检查分区威刚:
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'
问题1:这给了我什么,我期待在current_partition_range_boundary_value方面,但partition_rows(我希望是1000)返回5957行的每个分区。
最后,我尝试从Marc.foo SWITCH分区1至Marc.foo2
ALTER TABLE Marc.foo SWITCH PARTITION 1 to Marc.foo2 PARTITION 1
我希望,当我从Marc.foo2选择,我应该可以看到1000行与ID值从1到1000但我回到零行。
问题2:我做错了什么?