In SQL Server, why is a tinyint stored with 9B in the row. For some reason there seems to be an additional one byte at the end of the NULL bitmap mask.
USE tempdb ; GO CREATE TABLE tbl ( i TINYINT NOT NULL ) ; GO INSERT INTO tbl (i) VALUES (1) ; GO DBCC IND ('tempdb','tbl',-1) ; GO DBCC TRACEON (3604) ; -- Page dump will go the console GO DBCC PAGE ('tempdb',1,168,3) ; GO
Results (I reversed the bytes due to DBCC PAGE's showing the least significant byte first):
Record Size = 9B 10000500 01010000 00 TagA = 0x10 = 1B TagB = 0x00 = 1B Null Bitmap Offset = 0x0005 = 2B Our integer column = 0x01 = 1B Column Count = 0x0001 = 2B NULL Bitmap = 0x0000 = 2B (what!?)