Showing posts with label varbinary. Show all posts
Showing posts with label varbinary. Show all posts

Thursday, March 29, 2012

about 8KB limit

In SQL2005 with the option ROW_OVERFLOW_DATA the restriction of 8KB by row relaxed for tables that contain varchar, nvarchar, varbinary, sql_variant, or CLR user-defined type columns. In this case SQL Server use as best the page size, however I wonder what happen when this option is turned off.

For example, If a row size is of 3 KB and I have ROW_OVERFLOW_DATA OFF how SQL Server store my rows? there are about 2 KB of wasted space by page?

There is no such thing called ROW_OVERFLOW_DATA option. You cannot turn it on or off. It is based on the column type. If you have variable length columns, sql server allows you to store rows larger than 8k by pushing variable length column values off-row.

If your row size is 3KB fixed size, you will waste 2KB in each page. There is no way to work around and re-use those 2KB space.

Thanks

Sherry

about 8KB limit

In SQL2005 with the option ROW_OVERFLOW_DATA the restriction of 8KB by row relaxed for tables that contain varchar, nvarchar, varbinary, sql_variant, or CLR user-defined type columns. In this case SQL Server use as best the page size, however I wonder what happen when this option is turned off.

For example, If a row size is of 3 KB and I have ROW_OVERFLOW_DATA OFF how SQL Server store my rows? there are about 2 KB of wasted space by page?

There is no such thing called ROW_OVERFLOW_DATA option. You cannot turn it on or off. It is based on the column type. If you have variable length columns, sql server allows you to store rows larger than 8k by pushing variable length column values off-row.

If your row size is 3KB fixed size, you will waste 2KB in each page. There is no way to work around and re-use those 2KB space.

Thanks

Sherry

sql

Tuesday, March 6, 2012

A rewrite of the sp_help_revlogin procedure (use at own risk)

Use the view master.sys.sql_logins (new in 2005) to get at the varbinary passwords like you did in your Sql Server 2000 scripts (instead of using passwords from master.dbo.sysxlogins).

I have altered the sp_help_revlogin (from Microsoft article # 246133 )

PLEASE TEST/FIX before you use this:

if exists (select * from dbo.sysobjects where id = object_id(N'[dbo].[sp_help_revlogin_2005]') and OBJECTPROPERTY(id, N'IsProcedure') = 1)

drop procedure [dbo].[sp_help_revlogin_2005]

GO

SET QUOTED_IDENTIFIER OFF

GO

SET ANSI_NULLS OFF

GO

CREATE PROCEDURE sp_help_revlogin_2005 @.login_name sysname = NULL AS

DECLARE @.name sysname

DECLARE @.logintype char(1)

DECLARE @.logindisabled int

DECLARE @.binpwd varbinary (256)

DECLARE @.txtpwd sysname

DECLARE @.tmpstr varchar (256)

DECLARE @.SID_varbinary varbinary(85)

DECLARE @.SID_string varchar(256)

IF (@.login_name IS NULL)

DECLARE login_curs CURSOR FOR

SELECT sid, name, type, is_disabled FROM master.sys.server_principals

WHERE name <> 'sa' and type in ('S','U','G')

ELSE

DECLARE login_curs CURSOR FOR

SELECT sid, name, type, is_disabled FROM master.sys.server_principals

WHERE name = @.login_name

OPEN login_curs

FETCH NEXT FROM login_curs INTO @.SID_varbinary, @.name, @.logintype, @.logindisabled

IF (@.@.fetch_status = -1)

BEGIN

PRINT 'No login(s) found.'

CLOSE login_curs

DEALLOCATE login_curs

RETURN -1

END

SET @.tmpstr = '/* sp_help_revlogin_2005 script '

PRINT @.tmpstr

SET @.tmpstr = '** Generated '

+ CONVERT (varchar, GETDATE()) + ' on ' + @.@.SERVERNAME + ' */'

PRINT @.tmpstr

PRINT ''

PRINT 'DECLARE @.pwd sysname'

WHILE (@.@.fetch_status <> -1)

BEGIN

IF (@.@.fetch_status <> -2)

BEGIN

PRINT ''

SET @.tmpstr = '-- Login: ' + @.name

PRINT @.tmpstr

IF (@.logintype = 'G' OR @.logintype = 'U')

BEGIN -- NT authenticated account/group

IF @.logindisabled = 1

BEGIN -- NT login is denied access

SET @.tmpstr = 'EXEC master..sp_denylogin ''' + @.name + ''''

PRINT @.tmpstr

END

ELSE BEGIN -- NT login has access

SET @.tmpstr = 'EXEC master..sp_grantlogin ''' + @.name + ''''

PRINT @.tmpstr

END

END

ELSE IF (@.logintype = 'S')

BEGIN -- SQL Server authentication

SELECT @.binpwd = password_hash FROM master.sys.sql_logins WHERE SID = @.SID_varbinary

IF (@.binpwd IS NOT NULL)

BEGIN -- Non-null password

EXEC sp_hexadecimal @.binpwd, @.txtpwd OUT

SET @.tmpstr = 'SET @.pwd = CONVERT (nvarchar(128), ' + @.txtpwd + ')'

PRINT @.tmpstr

EXEC sp_hexadecimal @.SID_varbinary,@.SID_string OUT

SET @.tmpstr = 'EXEC master..sp_addlogin @.loginame = ''' + @.name

+ ''', @.passwd = @.pwd, @.sid = ' + @.SID_string + ', @.encryptopt = ''skip_encryption'''

END

ELSE BEGIN

-- Null password

EXEC sp_hexadecimal @.SID_varbinary,@.SID_string OUT

SET @.tmpstr = 'EXEC master..sp_addlogin @.loginame = ''' + @.name

+ ''', @.passwd = NULL, @.sid = ' + @.SID_string

END

PRINT @.tmpstr

END

END

FETCH NEXT FROM login_curs INTO @.SID_varbinary, @.name, @.logintype, @.logindisabled

END

CLOSE login_curs

DEALLOCATE login_curs

RETURN 0

GO

SET QUOTED_IDENTIFIER OFF

GO

SET ANSI_NULLS ON

GO

I've split this from the thread to which it was posted (http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=169513&SiteID=1), as it does not help with decrypting passwords. I've added a more suggestive title as well.

Thanks for your contribution.

Laurentiu

|||

Here's another rewrite of the sp_help_revlogin, which uses the new DDL and also outputs the password policy options:

http://blogs.msdn.com/lcris/archive/2006/04/03/567680.aspx

Thanks
Laurentiu