DBCC for SQL Server

--Check the index fragmentation situation

DBCC SHOWCONFIG (tablename)

Specific examples:

--Before the defragmentation

ALTER INDEX all on citation REBUILD

-After the defragmentation

--Extents Switches:extents Scanned-1

-AVG. Pages per Extent: Default 1 Zone 8 page, less than 8, with external fragmentation

-AVG. Bytes free per page: The higher the value of 8000 Bytes, the greater the internal fragmentation, or the filling factor is too low;

External: There are pages in the area that are not being used

Internal: There is no space left in the page to be used

DBCC IND (dbname,tablename,#)

--#: -1~2

--INDEXID: Index type id,0 represents a heap, 1 is a clustered index, and 2-250 represents a nonclustered index. You can find it on the Sys.indexs

--Page type:1 = Data page, 2 = index page, 3 = lob_mixed_page, 4 = lob_tree_page, ten = IAM Page

DBCC Traceob (3604)
DBCC page (dbname,pagefid,pagepid,#)

--#:0~3

sp_spaceused TableName

--Reserved:data + index_size + unused

--Data:data Page * 8k

--Index_size:index Page * 8k + IAM page * 8k

DBCC for SQL Server