Automatic fix for tempdb error related to 'ASPStateTempSessions' - asp.net

As per this how-to, I've successfully configured IIS on my XP-SP3 dev box for SQL Server 2008 Express to save ASP.NET session state information. I'm just using SQL Server because otherwise on every recompile, I was losing the session state which was obnoxious (having to re-login). But, I'm facing an annoying issue in that every time I restart SQL there's this error, and sometimes one or two other very similar friends:
The SELECT permission was denied on the object 'ASPStateTempSessions',
database 'tempdb', schema 'dbo'.
To fix the error, I just open Management Studio and edit the User Mapping for the login/dbo I'm using on the ASPState db, and re-add tempdb to that user with all but deny permissions. Apparently, once the right permissions are there, ASP.NET is able to automatically create the tables it uses. It just can't run that CreateTempTables sproc until the right security is there.
THE QUESTION...
Is there a way to not have to re-do this on every restart of the SQL Server?
I don't really care right now about keeping the temp data across restarts, but I would like to not have to go through this manual step just to get my web app working on localhost, which uses session state variables throughout. I suppose one could resort to some kind of stored procedure within SQL Server to accomplish the task for this machine when the service starts, to not have to do it manually. I'd accept such an answer as a quick fix. But, I'm also assuming there's a better recommended configuration or something. Not seeing an answer to this on the how-to guide or elsewhere here on StackOverflow.

Both answers seem valid; but with most things Microsoft, its all in the setup...
First uninstall the ASPState database by using the command:
aspnet_regsql –ssremove –E -S .
Note:
-E is to indicate you want to use integrated security connection.
-S informs what SQL server and SQL instance to use, and the "." (dot) specifies default local instance
Then re-install using the command:
aspnet_regsql –ssadd –sstype p –E -S .
Note:
The sstype has three options, t | p | c ... the first "t", tells the installer to host all stored procedures in the ASPState database, and all data in the tempdb. The second option "p" tells the installer to persist data to the ASPState database. The last option "c" allows you to specify a different 'custom' database to persist the session state data.
If you reinstall using the "-sstype p" you then need only to supply datareader/datawriter to the ASPState database for the user that's making the connection (in most cases, the application pool's identity in IIS).
The added benefit of persisting the data is that session state is retained even after a restart of the service. The only drawback is that you need to ensure the agent cleanup job is pruning old sessions regularly (it does this by default, every minute).
Important:
If you are running a cluster, you must persist session data. You're only option is to use sstype 'p' or 'c'.
Hope this sheds light on the issue!

For the record, I did find a way to do this.
The issue is that the tempdb is recreated from the model db each time the service restarts. The gist of the solution is to create a stored procedure that does the job, and then make that procedure run at startup.
Source code (credit to the link above) is as follows:
use master
go
-- remove an old version
drop proc AddAppTempDBOwner
go
-- the sp
create proc AddAppTempDBOwner as
declare #sql varchar(200)
select #sql = 'use tempdb' + char(13) + 'exec sp_addrolemember ''db_owner'', ''app'''
exec (#sql)
go
-- add it to the startup
exec sp_procoption 'AddAppTempDBOwner', 'startup', 'true'
go

Well done for finding the strangest way possible to do this.
The correct answer is as follows:
use master
go
EXEC sp_configure 'Cross DB Ownership Chaining', '1'
go
RECONFIGURE
go
EXEC sp_dboption 'ASPState', 'db chaining', 'true'
go

Related

Various difficulties creating ASP.NET Session tables via aspnet_regsql.exe

We're trying to move ASP.NET session state for one of our Azure web apps into a database, and it seems like the aspnet_regsql.exe tool is the way to go. Unfortunately, I'm getting stuck on a few issues below. It's an Azure SQL database, and I'm connecting using the server's admin account.
I initially wanted to add the session tables to our existing database, so I ran .\aspnet_regsql.exe -U adminusername -P adminpassword -S servername.database.windows.net -d databasename -ssadd -sstype c. Which throws the exception "Database 'databasename' already exists. Choose a different database name"
Omitting the database name and running it again throws the exception: "Execution Timeout Expired" after about 30 seconds, which is just the default for SqlCommand.CommandTimeout. This occurs while executing the "CREATE DATABASE" command. I tried creating a database manually, and it takes about 50 seconds for some reason. This database is S0 tier and is not under any load
Running aspnet_regsql again on the already-created database (because it's idempotent, right?) leads to the "Database already exists" error, as does pre-creating an empty database for it to start from.
There's no flag that lets me increase the timeout, and I can't set command timeout using the -C (connection string) flag
Adding the -sqlexportonly flag to generate a script and just running that directly doesn't work either (yes, I know I'm not supposed to run InstallSqlState.sql directly). It throws a whole load of error messages saying things like:
Reference to database and/or server name in 'msdb.dbo.sp_add_job' is not supported in this version of SQL Server.
USE statement is not supported to switch between databases.
Which makes me think this script might have some issues with an Azure SQL database...
Does anyone have any ideas?
Update:
It looks like all the errors involving 'msdb' are related to removing and re-adding a database job called 'Job_DeleteExpiredSessions'. Azure SQL doesn't support database jobs, so the only options I can see are
Run SQL on a VM instead (vastly more expensive, and I'd rather stick with the platform services than have to manage VMs)
Implement one of those "Elastic Job Agents"
Perhaps move the same functionality elsewhere (e.g. a stored proc)?
Turns out Microsoft has an article about how to do exactly what I need, which I somehow
missed during my searching yesterday. Hopefully this answer saves someone else a few hours of frustration. All the info you need is at https://azure.microsoft.com/en-au/blog/using-sql-azure-for-session-state/ earlier.
Note that YMMV since it's from 2010 and also says in scary red letters
"Microsoft does not support SQL Session State Management using SQL Azure databases for ASP.net applications"
Nevertheless, they provide a working script that seems to do exactly what I need.

ASP.Net SQL Server Session State vs Persistent Session state

I am researching and trying some things out with regards to the automatic saving of session variables into SQL Server. I have found this link discussing SQL Server session state (call it 'Option 1') and this link discussing Persistent SQL Server session state (call it 'Option 2').
The main difference seems to be that with Option 1, if the machine running SQL Server is turned off, the session data is lost, contrary to Option 2 which persists it. In Option 1 it seems that the process makes use of the tempdb, whereas, Option 2 seems to persist the session data through the use of the ASPState database.
I have a few questions that I can't seem to find any answers to:
In the first option, the article discusses the configuration required in the web config with regards to the < sessionState > tag. This is not added to the persistent case (Option 2). Should the < sessionState > be the same in both cases?
I have tried the second option as that seems to be more in-line to my case scenario. I started by downloading PersistSQLState.exe which simply self-extracts the InstallPersistSqlState.sql and UninstallPersistSqlState.sql scripts. I ran the InstallPersistSQLState.sql which completed successfully and created the 'ASPState' database in the SQL Server. I set the < sessionState > tag using the format stated in Option 2 as discussed in point 1) above.
Upon running the app I got the below error:
"Unable to use SQL Server because either ASP.NET version 2.0 Session State is not installed on the SQL server, or ASP.NET does not have permission to run the dbo.TempGetVersion stored procedure. If the ASP.NET Session State schema has not been installed, please install ASP.NET Session State SQL Server version 2.0 or above. If the schema has been installed, please grant execute permission on the dbo.TempGetVersion stored procedure to either the ASP.NET application pool identity, or the Sql Server user specified in the sqlConnectionString attribute."
This outlines 2 things: the Asp.Net Version 2.0 Session state potentially being not installed yet, and the process being unable to run the dbo.TempGetVersion stored procedure (for various reasons).
The stored procedure dbo.TempGetVersion does not exist in the ASPState database created by the InstallPersistSqlState.sql script. Is this stored procedure actually related to the tempdb (non-persistent) and therefore why the schema of the ASPState does not include it?
Is this the Asp.Net Version 2.0 Session state that needs to be installed? If so what is the process to be followed?! Should it be installed in the ASPState database after running the InstallPersistSQLState.sql script? If not, what is to be done exactly? There is nothing related to this ".exe" in either Option 1 or Option 2!
Finally, I have also tried uninstalling the persistent case instead run the scripts related to the Option 1 (non-persistent). In this case, the scripts provided in the first link above do not seem to work; returning 2 errors with jobs not being found ?!. Anyone has any idea why this would happen and do the correct scripts exist in some kind of online location?!
Any help would be appreciated as documentation seems poor on this subject.
The Option 1 and Option 2 articles as listed in my question are misleading, which is why I ended up wasting a whole day trying to make it work with the wrong info: I just did not have the right article at hand!
The below is what I ended up doing to implement persistent session state. Hope it can prove helpful to anyone wanting to implement the same thing.
On the machine open CMD in Administrator mode.
Change directory to .Net framework folder:
cd C:\Windows\Microsoft.NET\Framework\v4.0.30319
Run this command:
aspnet_regsql.exe -S "SQLServerInstanceName" -U "Username" -P "Password" -ssadd -sstype p
Small explanation of command in Point 2 above.
Aspnet_regsql.exe - is the .exe that installs Asp.Net Session state on the machine.
-S defines SQL Server instance name
-U defines Username -
-P defines Password
ssadd defines creating a new database for session state
sstype defines the type of session state. p is persistent.
Finally, in the web.config of the Asp.Net application where persistent session state is to be implemented, change the tag to look like the below:
< sessionState mode="SQLServer" sqlConnectionString="data source=127.0.0.1\sqltest;User ID=*****;Password=******" cookieless="false" timeout="20" / >
For full info visit this article and refer to the SQL Server mode.

SQL Job, Linked Server, Domain Account

I think I have tried everything but I can't figure out how to set up an SQL Job that have a T-SQL Step that performs a SELECT on a linked server.
1) I got a Domain user mydomain\SQLJob
2) I got a SQL 2017 server 'JOBSERVER' with the SQL Agent running log on as a domain user mydomain\sv_agent (this cannot be changed). No futher rights should be given to this user either.
3) On the JOBSERVER I created a linked server
EXEC sp_addlinkedserver 'LINKEDSERVER'
4) mydomain\SQLJob is data reader on a database on LINKEDSERVER
5) I am able to do a SELECT * FROM LINKEDSERVER... from JOBSERVER in a regular Query Window.
On JOBSERVER I have tried
ALTER DATABASE MyDatabase SET TRUSTWORTHY ON
And then set the job to execute in MyDatabase
I have also tried
Job Step Properties > Advanced > Run as user > mydomain\SQLJob
I have tried adding mydomain\SQLJob to the linked server on JOBSERVER both with and without Impersonate
Could someone let me know what the correct steps are ?
Thanks
I found another post that stated it could not be done.
What I did instead was changing the T-SQL to a PowerShell script. Here the Run As works just fine.

Why does my tempdb reset permissions when the server is rebooted?

The past two times we have rebooted our sql server, our website has gone down. The reason appears to be because the tempdb is getting recreated and the ASPState user is losing permission to read/write to the tempdb (it is an ASP site and session data is stored in the sql server)
This was not a problem until about two weeks ago. Does anyone know how I can prevent the sql server from resetting tempdb permissions after a reboot? Or why this only started happening recently? We are using MS SQL Server 2005.
First off, you shouldn't assign permissions to the tempdb directly. For the obvious reasons that it gets recreated on every reboot.
Which actually raises a question: why do you need to have direct permissions to this database anyway?
You don't need any permissions beyond just being able to connect to sql server in order to create temp tables. However, if you are creating real tables in the tempdb, then I highly suggest you change this to use a dedicated database for this purpose.
UPDATE
Based on Martin's comment all I can say is wow. I would never even have considered that this would have been an option.
Okay, now that I've recovered from the shock.
Create a new job in sql server that executes on a schedule. The schedule should be set to "Start Automatically whenever SQL Server Agent Starts". The job should recreate your necessary tempdb permissions.
In a nutshell, when the server is rebooted the SQL Server Agent will be restarted (provided the service is set that way). When it restarts it will kick off this job that will then fix your permissions. I'd expect the site to remain down for only a few seconds more than it takes for SQL server to completely restart.
I know this is an old question but found some new information regarding the tempdb behaviour on restarting.
The tempdb is essentially recreated from the 'model' db and that is the reason why all changes to it are lost. If you make a change to persist your changes even after restart make the same changes to the 'model' db as you would to the 'tempdb'.
Have a look at the following: Does tempdb Get Recreated From model at Startup?
The Model database is used as a template for TempDB. Add users and permissions to model and the same usere and permissions will be used on TempDB. I do not say that this is the optimal solution for every case but it worked for me in a situation where an application needed speciffic TempDB access.
Create a startup script on sql Server as below:
use master
go
drop proc AddAppTempDBOwner
go
create proc AddAppTempDBOwner as
declare #sql varchar(200)
select #sql = 'use tempdb' + char(13)
+ 'exec sp_addrolemember ''db_owner'', ''app'''
exec (#sql)
go
exec sp_procoption 'AddAppTempDBOwner', 'startup', 'true'
go
Here's a script to create a startup stored procedure, which loops over Logins and creates Users in tempdb as db_owner. This script does not have harcoded logins.
As a result even after SQL machine restarts all SQL logins will have privileges to access tempdb.
USE [master]
GO
IF EXISTS ( SELECT *
FROM sysobjects
WHERE id = object_id(N'AddUsersToTempDb')
and OBJECTPROPERTY(id, N'IsProcedure') = 1 )
BEGIN
DROP PROCEDURE AddUsersToTempDb
END
GO
CREATE PROCEDURE AddUsersToTempDb
AS
DECLARE #loginname as NVARCHAR(100);
DECLARE Login_Cursor CURSOR FOR
SELECT loginname
FROM master..syslogins
OPEN Login_Cursor;
FETCH NEXT FROM Login_Cursor INTO #loginname;
WHILE ##FETCH_STATUS = 0
BEGIN
IF (#loginname <> 'sa' AND (NOT #loginname LIKE '##%') AND (NOT #loginname LIKE '%\%'))
BEGIN
PRINT #loginname
IF EXISTS(SELECT * FROM [tempdb].sys.database_principals WHERE type_desc = 'SQL_USER' AND name = #loginname)
PRINT ' - user already exists'
ELSE
BEGIN
PRINT ' - creating user'
DECLARE #Sql VARCHAR(MAX)
SET #Sql =
'USE Tempdb' + char(13) +
'CREATE USER ' + #loginname + ' FOR LOGIN ' + #loginname + char(13) +
'EXEC sp_addrolemember db_owner, ' + #loginname
EXEC (#Sql)
END
END
FETCH NEXT FROM Login_Cursor INTO #loginname;
END;
CLOSE Login_Cursor;
DEALLOCATE Login_Cursor;
GO
EXEC sp_procoption 'AddUsersToTempDb', 'startup', 'true'
GO
The tempdb database in SQL server is (from everything I've ever read, heard, or experienced) completely dropped and recreated every time the service is started up. Thus, anything stored within or written to that database, including roles, users, or other access right settings, will be wiped out. Barring some fussy code to set/reset them whenever the instance starts up, I don't think you can work around this. (I don't think anything set in the model database gets copied over to tempdb when it's created, but I've never even thought about that...)
Are any such settings being written to that databases? Are you sure that your system has not been recently changed or updated to do so? Possibly relevant, how often does the SQL instance get stopped and restarted? (It's not uncommon--if not wise--for SQL to run for months if not yers without a restart...)

How To Query A Database That's Being Used By Asp.Net

I have a Sql Server 2008 Express database file that's currently being used by an ASP.NET application, and I'm not sure how to query the database without taking the website down.
I'm unable to copy the database files (.mdf and .ldf files) to another directory, since they're in use by the web server. Also, if I attach the databases to an instance of the sql server (using the 'Create Database [DB name] on (filename = '[DB filename.mdf]') for attach;' command at the sqlcmd prompt), then the application pool user becomes unable to access the database (i.e. the webpages start producing http 500 errors. I think this might have to do with the username for the application pool becoming somehow divorced from the login credentials in the sql server database).
Any suggestions? I realize this is probably a newbie question, since it seems like a rather fundamental task. However, due to my inexperience, I really don't know what the answer is, and I'm pretty stumped at this point, since I've tried a couple of different things.
Thanks!
Andrew
if I attach the databases to an instance of the sql server (using the 'Create Database [DB name] on (filename = '[DB filename.mdf]') for attach;' command at the sqlcmd prompt),
Don't do this to a live database - it's attempting to be setup an MDF to be written to by two different databases...
Use Backup/Restore
As you've found, Attach/ReAttach requires the database to be offline - use the Backup/Restore functionality:
MSDN: Using SSMS to Backup the Database
MSDN: Using SSMs to Restore the Backup
Be aware that the backup/restore doesn't maintain logins (& jobs if you have any associated with the database) - you'll have to recreate & sync if using an account other than those with uber access.
Maybe Linked Server would work?
Another alternative would be to setup another SQL Server Express/etc instance on a different box, and use the Linked Server functionality to create a connection to the live/prod data. Use a different account than the one used for the ASP application...

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