查出資料庫中所有索引的碎裂狀態
可以查出資料庫中所有索引的碎裂狀態，如下 T-SQL 語法：
SELECT OBJECT_NAME(dt.object_id) ,
si.name ,
dt.avg_fragmentation_in_percent,
dt.avg_page_space_used_in_percent
FROM
(SELECT object_id ,
index_id ,
avg_fragmentation_in_percent,
avg_page_space_used_in_percent
FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL, NULL, ‘DETAILED’)
WHERE index_id 0
) AS dt –does not return information about heaps
INNER JOIN sys.indexes si
ON si.object_id = dt.object_id
AND si.index_id = dt.index_id
自動幫你算出哪些索引需要被重建或重組，而且直接幫你把 ALTER INDEX 的 T-SQL 都寫好，程式碼如下：
SELECT ‘ALTER INDEX [‘ + ix.name + ‘] ON [‘ + s.name + ‘].[‘ + t.name + ‘] ‘ +
CASE
WHEN ps.avg_fragmentation_in_percent > 15
THEN ‘REBUILD’
ELSE ‘REORGANIZE’
END +
CASE
WHEN pc.partition_count > 1
THEN ‘ PARTITION = ‘ + CAST(ps.partition_number AS nvarchar(MAX))
ELSE "
END,
avg_fragmentation_in_percent
FROM sys.indexes AS ix
INNER JOIN sys.tables t
ON t.object_id = ix.object_id
INNER JOIN sys.schemas s
ON t.schema_id = s.schema_id
INNER JOIN
(SELECT object_id ,
index_id ,
avg_fragmentation_in_percent,
partition_number
FROM sys.dm_db_index_physical_stats (DB_ID(), NULL, NULL, NULL, NULL)
) ps
ON t.object_id = ps.object_id
AND ix.index_id = ps.index_id
INNER JOIN
(SELECT object_id,
index_id ,
COUNT(DISTINCT partition_number) AS partition_count
FROM sys.partitions
GROUP BY object_id,
index_id
) pc
ON t.object_id = pc.object_id
AND ix.index_id = pc.index_id
WHERE ps.avg_fragmentation_in_percent > 10
AND ix.name IS NOT NULL