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  • Relative path reference in WebConfig.ConnectionString

    - by Ngu Soon Hui
    Is it possible to specify a relative path reference in connectionstring, attachDbFileName property in a web.config? For example, In my database is located in the App_data folder, I can easily specify the AttachDBFilename as|DataDirectory|\mydb.mdf and the |Datadirectory| will automatically resolve to the correct path. Now, suppose that web.config file is located in A folder, but the database is located in B\App_data folder, where A and B folder is located in the same folder. Is there anyway to use relative path reference to resolve to the correct path?

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  • How can I manage SQL CE databases in SQL Server Management Studio?

    - by Edward Tanguay
    I created a SDF (SQL CE) database with Visual Studio 2008 (Add / New Item / Local Database). Is it possible to edit this database with SQL Server Management Studio? I tried to attach it but it only offered .mdf and attaching a .sdf file results in "failed to retrieve data for this request". If so, is it possible to create SDF files with Management Studio as well? Or are we stuck with the simple interface of the Visual Studio 2008 database manager?

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  • Shrink Sql Server database

    - by hani
    My SQL Server 2008 database file (.mdf) file is nearly 24 MB but the log file grown upto 15 GB. If I want to shrink database what are the important points to take into consideration? Will shrink causes any index fragmentation and does it affect my database performance?

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  • missing a using directive or an assembly reference

    - by cire1507
    I'm in the process of writing a small asp.net mvc application that is using the northwind.mdf. When building the solution I get this error: Error 1 The type or namespace name 'Order' could not be found (are you missing a using directive or an assembly reference?) Order is a table in the northwind database. any help is most appreciated.

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  • Filestream in Sql Server 2008 Express

    - by Xaitec
    i tried to get it to work but i never seem to have to luck, i go a code snippet for a blog and still no dice. This is the code. EXEC sp_configure filestream_access_level, 1 GO RECONFIGURE GO CREATE DATABASE NorthPole ON PRIMARY ( NAME = NorthPoleDB, FILENAME = 'C:\Temp\NP\NorthPoleDB.mdf' ), FILEGROUP NorthPoleFS CONTAINS FILESTREAM( NAME = NorthPoleFS, FILENAME = 'C:\Temp\NP\NorthPoleFS') LOG ON ( NAME = NorthPoleLOG, FILENAME = 'C:\Temp\NP\NorthPoleLOG.ldf') GO

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  • WebService doesn't read web.config

    - by phenevo
    Hi, I've got 3 connectionstrings in web.config, and I used theirs like this: using (SqlConnection connection = new SqlConnection(ConfigurationManager.ConnectionStrings["SomeName"].ConnectionString)) Every metgod is called by winforms application. One of webmethods doesn't work properly because it reads only one connectionString: data source=.\\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true It's not a connectionString from my web.config . I invoke every method in the same way. How it's impossible ??

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  • How do you stop a user-instance of Sql Server? (Sql Express user instance database files locked, eve

    - by Bittercoder
    When using SQL Server Express 2005's User Instance feature with a connection string like this: <add name="Default" connectionString="Data Source=.\SQLExpress; AttachDbFilename=C:\My App\Data\MyApp.mdf; Initial Catalog=MyApp; User Instance=True; MultipleActiveResultSets=true; Trusted_Connection=Yes;" /> We find that we can't copy the database files MyApp.mdf and MyApp_Log.ldf (because they're locked) even after stopping the SqlExpress service, and have to resort to setting the SqlExpress service from automatic to manual startup mode, and then restarting the machine, before we can then copy the files. It was my understanding that stopping the SqlExpress service should stop all the user instances as well, which should release the locks on those files. But this does not seem to be the case - could anyone shed some light on how to stop a user instance, such that it's database files are no longer locked? Update OK, I stopped being lazy and fired up Process Explorer. Lock was held by sqlserver.exe - but there are two instances of sql server: sqlserver.exe PID: 4680 User Name: DefaultAppPool sqlserver.exe PID: 4644 User Name: NETWORK SERVICE The file is open by the sqlserver.exe instance with the PID: 4680 Stopping the "SQL Server (SQLEXPRESS)" service, killed off the process with PID: 4644, but left PID: 4680 alone. Seeing as the owner of the remaining process was DefaultAppPool, next thing I tried was stopping IIS (this database is being used from an ASP.Net application). Unfortunately this didn't kill the process off either. Manually killing off the remaining sql server process does remove the open file handle on the database files, allowing them to be copied/moved. Unfortunately I wish to copy/restore those files in some pre/post install tasks of a WiX installer - as such I was hoping there might be a way to achieve this by stopping a windows service, rather then having to shell out to kill all instances of sqlserver.exe as that poses some problems: Killing all the sqlserver.exe instances may have undesirable consequencies for users with other Sql Server instances on their machines. I can't restart those instances easily. Introduces additional complexities into the installer. Does anyone have any further thoughts on how to shutdown instances of sql server associated with a specific user instance?

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  • Failed to update database because it is read-only

    - by Attilah
    I have set up my website to use ASP.NET Membership. it all works fine when trying to use it on my development machine but when I put it on the web server and try to log in, I get this error : "Failed to update database "C:\INETPUB\WWWROOT\APP_DATA\ASPNETDB.MDF" because the database is read-only. "

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  • Changing default logical filename in SQL 2005

    - by Andrew
    I have a issue about creating databases in SQL 2005. I want to be able to change the default logical filename for the mdf file. At the moment the log logical filename ends in _log by default. I want the data logical filename to automatically end with _data for consistency. Is there a way i can set this? Andrew

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  • Restoring multiple database backups in a transaction

    - by Raghu Dodda
    I wrote a stored procedure that restores as set of the database backups. It takes two parameters - a source directory and a restore directory. The procedure looks for all .bak files in the source directory (recursively) and restores all the databases. The stored procedure works as expected, but it has one issue - if I uncomment the try-catch statements, the procedure terminates with the following error: error_number = 3013 error_severity = 16 error_state = 1 error_message = DATABASE is terminating abnormally. The weird part is sometimes (it is not consistent) the restore is done even if the error occurs. The procedure: create proc usp_restore_databases ( @source_directory varchar(1000), @restore_directory varchar(1000) ) as begin declare @number_of_backup_files int -- begin transaction -- begin try -- step 0: Initial validation if(right(@source_directory, 1) <> '\') set @source_directory = @source_directory + '\' if(right(@restore_directory, 1) <> '\') set @restore_directory = @restore_directory + '\' -- step 1: Put all the backup files in the specified directory in a table -- declare @backup_files table ( file_path varchar(1000)) declare @dos_command varchar(1000) set @dos_command = 'dir ' + '"' + @source_directory + '*.bak" /s/b' /* DEBUG */ print @dos_command insert into @backup_files(file_path) exec xp_cmdshell @dos_command delete from @backup_files where file_path IS NULL select @number_of_backup_files = count(1) from @backup_files /* DEBUG */ select * from @backup_files /* DEBUG */ print @number_of_backup_files -- step 2: restore each backup file -- declare backup_file_cursor cursor for select file_path from @backup_files open backup_file_cursor declare @index int; set @index = 0 while(@index < @number_of_backup_files) begin declare @backup_file_path varchar(1000) fetch next from backup_file_cursor into @backup_file_path /* DEBUG */ print @backup_file_path -- step 2a: parse the full backup file name to get the DB file name. declare @db_name varchar(100) set @db_name = right(@backup_file_path, charindex('\', reverse(@backup_file_path)) -1) -- still has the .bak extension /* DEBUG */ print @db_name set @db_name = left(@db_name, charindex('.', @db_name) -1) /* DEBUG */ print @db_name set @db_name = lower(@db_name) /* DEBUG */ print @db_name -- step 2b: find out the logical names of the mdf and ldf files declare @mdf_logical_name varchar(100), @ldf_logical_name varchar(100) declare @backup_file_contents table ( LogicalName nvarchar(128), PhysicalName nvarchar(260), [Type] char(1), FileGroupName nvarchar(128), [Size] numeric(20,0), [MaxSize] numeric(20,0), FileID bigint, CreateLSN numeric(25,0), DropLSN numeric(25,0) NULL, UniqueID uniqueidentifier, ReadOnlyLSN numeric(25,0) NULL, ReadWriteLSN numeric(25,0) NULL, BackupSizeInBytes bigint, SourceBlockSize int, FileGroupID int, LogGroupGUID uniqueidentifier NULL, DifferentialBaseLSN numeric(25,0) NULL, DifferentialBaseGUID uniqueidentifier, IsReadOnly bit, IsPresent bit ) insert into @backup_file_contents exec ('restore filelistonly from disk=' + '''' + @backup_file_path + '''') select @mdf_logical_name = LogicalName from @backup_file_contents where [Type] = 'D' select @ldf_logical_name = LogicalName from @backup_file_contents where [Type] = 'L' /* DEBUG */ print @mdf_logical_name + ', ' + @ldf_logical_name -- step 2c: restore declare @mdf_file_name varchar(1000), @ldf_file_name varchar(1000) set @mdf_file_name = @restore_directory + @db_name + '.mdf' set @ldf_file_name = @restore_directory + @db_name + '.ldf' /* DEBUG */ print 'mdf_logical_name = ' + @mdf_logical_name + '|' + 'ldf_logical_name = ' + @ldf_logical_name + '|' + 'db_name = ' + @db_name + '|' + 'backup_file_path = ' + @backup_file_path + '|' + 'restore_directory = ' + @restore_directory + '|' + 'mdf_file_name = ' + @mdf_file_name + '|' + 'ldf_file_name = ' + @ldf_file_name restore database @db_name from disk = @backup_file_path with move @mdf_logical_name to @mdf_file_name, move @ldf_logical_name to @ldf_file_name -- step 2d: iterate set @index = @index + 1 end close backup_file_cursor deallocate backup_file_cursor -- end try -- begin catch -- print error_message() -- rollback transaction -- return -- end catch -- -- commit transaction end Does anybody have any ideas why this might be happening? Another question: is the transaction code useful ? i.e., if there are 2 databases to be restored, will SQL Server undo the restore of one database if the second restore fails?

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  • [ADO.NET ERRROR]: CREATE DATABASE permission denied in database 'master'. An attempt to attach an au

    - by Mark Cidade
    Anyone seen this before? CREATE DATABASE permission denied in database 'master'. An attempt to attach an auto-named database for file C:\Documents and Settings\..\App_Data\HelloWorld.mdf failed. A database with the same name exists, or specified file cannot be opened, or it is located on UNC share. I'm asking on a friend's behalf. I've sent him these links: http://blog.benhall.me.uk/2008/03/sql-server-and-vista-create-database.html http://forums.microsoft.com/MSDN/ShowPost.aspx?PostID=702726&SiteID=1

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  • Default MVC Web Application Database

    - by wows
    When setting up a new ASP.NET MVC Web Application, the default connection string inside Web.Config is something like this: connectionString="data source=.\SQLEXPRESS;Integrated Security=SSPI;AttachDBFilename=|DataDirectory|aspnetdb.mdf;User Instance=true" I'm just wanting to play around with logging in and registering, etc but when I run the app it obviously can't find a SQL database. What database with what tables do I need to setup to do this? I have SQL Server 2005 Standard installed on my system, is that enough? Thanks.

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  • Why am I unable to create a trigger using my SqlCommand?

    - by acidzombie24
    The line cmd.ExecuteNonQuery(); cmd.CommandText CREATE TRIGGER subscription_trig_0 ON subscription AFTER INSERT AS UPDATE user_data SET msg_count=msg_count+1 FROM user_data JOIN INSERTED ON user_data.id = INSERTED.recipient; The exception: Incorrect syntax near the keyword 'TRIGGER'. Then using VS 2010, connected to the very same file (a mdf file) I run the query above and I get a success message. WTF!

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  • Program not connecting to new database

    - by Manoj
    Hi, I moved a VS Solution file from an old PC to a new PC. When I opened the solution in VS2010, I found that the database connections in database explorer was not present. Now I want the project to connect to a SQL Server database which is local to the new PC. I have moved the database files (.ldf and .mdf) to the new location and created new connection in Database explorer. But the program seems to be not fetching any data when I run it. What are the other changes I need to do?

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  • Gridview Datasource Server error

    - by salvationishere
    I am developing a C# VS 2008 and SQL Server 2008 website. However, I get the below error now when I first run this: The DataSourceID of 'GridView1' must be the ID of a control of type IDataSource. A control with ID 'AdventureWorks3.mdf' could not be found What is causing this error? Here is my default.aspx file. I have configured GridView1 to use my AdventureWorks3.mdf file, stored in my App_Data folder. Do I need to add this folder name to this ASPX file? <%@ Page Language="C#" MasterPageFile="~/Site.master" AutoEventWireup="true" CodeFile="Default.aspx.cs" Inherits="_Default" Title="Untitled Page" %> <asp:Content ID="Content1" ContentPlaceHolderID="MainContent" Runat="Server"> <asp:Panel runat="server" ID="AuthenticatedMessagePanel"> <asp:Label runat="server" ID="WelcomeBackMessage"></asp:Label> <table> <tr > <td> <asp:Label ID="tableLabel" runat="server" Font-Bold="True" Text="Select target table:"></asp:Label> </td> <td> <asp:Label ID="inputLabel" runat="server" Font-Bold="True" Text="Select input file:"></asp:Label> </td></tr> <tr><td valign="top"> <asp:Label ID="feedbackLabel" runat="server"></asp:Label> <asp:GridView ID="GridView1" runat="server" style="WIDTH: 400px;" CellPadding="4" ForeColor="#333333" GridLines="None" onselectedindexchanged="GridView1_SelectedIndexChanged" AutoGenerateSelectButton="True" DataSourceID="AdventureWorks3.mdf" > <RowStyle BackColor="#F7F6F3" ForeColor="#333333" /> <FooterStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <PagerStyle BackColor="#284775" ForeColor="White" HorizontalAlign="Center" /> <SelectedRowStyle BackColor="#E2DED6" Font-Bold="True" ForeColor="#333333" /> <HeaderStyle BackColor="#5D7B9D" Font-Bold="True" ForeColor="White" /> <EditRowStyle BackColor="#999999" /> <AlternatingRowStyle BackColor="White" ForeColor="#284775" /> </asp:GridView> </td> <td valign="top"> <input id="uploadFile" type="file" size="26" runat="server" name="uploadFile" title="UploadFile" class="greybar" enableviewstate="True" /> </td></tr> </table> </asp:Panel> <asp:Panel runat="Server" ID="AnonymousMessagePanel"> <asp:HyperLink runat="server" ID="lnkLogin" Text="Log In" NavigateUrl="~/Login.aspx"> </asp:HyperLink> </asp:Panel> </asp:Content> Or what about my ASPX.CS file? Is this the problem? using System; using System.Collections; using System.Configuration; using System.Data; using System.Linq; using System.Web; using System.Web.Security; using System.Web.UI; using System.Web.UI.HtmlControls; using System.Web.UI.WebControls; using System.Web.UI.WebControls.WebParts; using System.Xml.Linq; using System.Collections.Generic; using System.IO; using System.Drawing; using System.ComponentModel; using System.Data.SqlClient; using ADONET_namespace; using System.Security.Principal; //using System.Windows; public partial class _Default : System.Web.UI.Page //namespace AddFileToSQL { //protected System.Web.UI.HtmlControls.HtmlInputFile uploadFile; protected System.Web.UI.HtmlControls.HtmlInputButton btnOWrite; protected System.Web.UI.HtmlControls.HtmlInputButton btnAppend; protected System.Web.UI.WebControls.Label Label1; protected static string inputfile = ""; public static string targettable; public static string selection; // Number of controls added to view state protected int default_NumberOfControls { get { if (ViewState["default_NumberOfControls"] != null) { return (int)ViewState["default_NumberOfControls"]; } else { return 0; } } set { ViewState["default_NumberOfControls"] = value; } } protected void uploadFile_onclick(object sender, EventArgs e) { } protected void Load_GridData() { GridView1.DataSource = ADONET_methods.DisplaySchemaTables(); GridView1.DataBind(); } protected void btnOWrite_Click(object sender, EventArgs e) { if (uploadFile.PostedFile.ContentLength > 0) { feedbackLabel.Text = "You do not have sufficient access to overwrite table records."; } else { feedbackLabel.Text = "This file does not contain any data."; } } protected void btnAppend_Click(object sender, EventArgs e) { string fullpath = Page.Request.PhysicalApplicationPath; string path = uploadFile.PostedFile.FileName; if (File.Exists(path)) { // Create a file to write to. try { StreamReader sr = new StreamReader(path); string s = ""; while (sr.Peek() > 0) s = sr.ReadLine(); sr.Close(); } catch (IOException exc) { Console.WriteLine(exc.Message + "Cannot open file."); return; } } if (uploadFile.PostedFile.ContentLength > 0) { inputfile = System.IO.File.ReadAllText(path); Session["Message"] = inputfile; Response.Redirect("DataMatch.aspx"); } else { feedbackLabel.Text = "This file does not contain any data."; } } protected void Page_Load(object sender, EventArgs e) { if (Request.IsAuthenticated) { WelcomeBackMessage.Text = "Welcome back, " + User.Identity.Name + "!"; // Reference the CustomPrincipal / CustomIdentity CustomIdentity ident = User.Identity as CustomIdentity; if (ident != null) WelcomeBackMessage.Text += string.Format(" You are the {0} of {1}.", ident.Title, ident.CompanyName); AuthenticatedMessagePanel.Visible = true; AnonymousMessagePanel.Visible = false; //if (!Page.IsPostBack) //{ // Load_GridData(); //} } else { AuthenticatedMessagePanel.Visible = false; AnonymousMessagePanel.Visible = true; } } protected void GridView1_SelectedIndexChanged(object sender, EventArgs e) { GridViewRow row = GridView1.SelectedRow; targettable = row.Cells[2].Text; } }

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  • WTF why does this SQL work in VS but not in CODE?

    - by acidzombie24
    The line cmd.ExecuteNonQuery(); cmd.CommandText CREATE TRIGGER subscription_trig_0 ON subscription AFTER INSERT AS UPDATE user_data SET msg_count=msg_count+1 FROM user_data JOIN INSERTED ON user_data.id = INSERTED.recipient; The exception: Incorrect syntax near the keyword 'TRIGGER'. Then using VS 2010, connected to the very same file (a mdf file) i run the query above and i get a success message. WTF!

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  • Using database on another development machine

    - by Cipher
    Hi, I am developing an ASP.NET website. I wanted to shift whole of my work to another PC of mine. I copied the website to the other PCOpenCreate ASP.NET folderApp_Data and pasted the database.mdf and database.ldf files there. I was getting some exception when I was trying to run the website as it showed the "could not open the connection from con.open()". Is there some other step too that I am missing?

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  • Why does this SQL work in VS but not in code?

    - by acidzombie24
    The line cmd.ExecuteNonQuery(); cmd.CommandText CREATE TRIGGER subscription_trig_0 ON subscription AFTER INSERT AS UPDATE user_data SET msg_count = msg_count + 1 FROM user_data JOIN INSERTED ON user_data.id = INSERTED.recipient; The exception: Incorrect syntax near the keyword 'TRIGGER'. Then using VS 2010, connected to the very same file (a mdf file) i run the query above and i get a success message.

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  • SQLExpress service unable to start Error code 17053

    - by Chris Sobolewski
    A user was instructed by their software support to upgrade a program and install SQLExpress as part of the installation process. Since that time, the service has been able to start, citing error 17053, which appears to be an authentication issue. Here is the error log: 2011-01-11 13:17:45.50 Server Microsoft SQL Server 2005 - 9.00.3042.00 (Intel X86) Feb 9 2007 22:47:07 Copyright (c) 1988-2005 Microsoft Corporation Express Edition on Windows NT 5.1 (Build 2600: Service Pack 2) 2011-01-11 13:17:45.50 Server (c) 2005 Microsoft Corporation. 2011-01-11 13:17:45.50 Server All rights reserved. 2011-01-11 13:17:45.50 Server Server process ID is 3332. 2011-01-11 13:17:45.50 Server Authentication mode is WINDOWS-ONLY. 2011-01-11 13:17:45.50 Server Logging SQL Server messages in file 'c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\ERRORLOG'. 2011-01-11 13:17:45.52 Server This instance of SQL Server last reported using a process ID of 2332 at 11/10/2010 2:15:24 PM (local) 11/10/2010 7:15:24 PM (UTC). This is an informational message only; no user action is required. 2011-01-11 13:17:45.52 Server Error: 17053, Severity: 16, State: 1. 2011-01-11 13:17:45.52 Server UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered. 2011-01-11 13:17:45.52 Server Registry startup parameters: 2011-01-11 13:17:45.52 Server -d c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\master.mdf 2011-01-11 13:17:45.52 Server -e c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\LOG\ERRORLOG 2011-01-11 13:17:45.52 Server -l c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\mastlog.ldf 2011-01-11 13:17:45.52 Server Error: 17113, Severity: 16, State: 1. 2011-01-11 13:17:45.52 Server Error 3(The system cannot find the path specified.) occurred while opening file 'c:\Program Files\Microsoft SQL Server\MSSQL.1\MSSQL\DATA\master.mdf' to obtain configuration information at startup. An invalid startup option might have caused the error. Verify your startup options, and correct or remove them if necessary. 2011-01-11 13:17:45.52 Server Error: 17053, Severity: 16, State: 1. 2011-01-11 13:17:45.52 Server UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered. 4 Server Error: 17053, Severity: 16, State: 1. 2011-01-11 13:08:21.34 Server UpdateUptimeRegKey: Operating system error 5(Access is denied.) encountered. 12:47:20.85 spid5s SQL Trace ID 1 was started by login "sa". 2011-01-11 12:47:20.90 spid5s Starting up database 'mssqlsystemresource'. 2011-01-11 12:47:20.93 spid5s The resource database build version is 9.00.3042. This is an informational message only. No user action is required. 2011-01-11 12:47:21.21 spid5s Error: 15466, Severity: 16, State: 1. 2011-01-11 12:47:21.21 spid5s An error occurred during decryption. 2011-01-11 12:47:21.38 spid8s Starting up database 'model'. 2011-01-11 12:47:21.38 Server Error: 17182, Severity: 16, State: 1. 2011-01-11 12:47:21.38 Server TDSSNIClient initialization failed with error 0x5, status code 0x90. 2011-01-11 12:47:21.38 Server Error: 17182, Severity: 16, State: 1. 2011-01-11 12:47:21.38 Server TDSSNIClient initialization failed with error 0x5, status code 0x1. 2011-01-11 12:47:21.38 Server Error: 17826, Severity: 18, State: 3. 2011-01-11 12:47:21.38 Server Could not start the network library because of an internal error in the network library. To determine the cause, review the errors immediately preceding this one in the error log. 2011-01-11 12:47:21.38 Server Error: 17120, Severity: 16, State: 1. 2011-01-11 12:47:21.38 Server SQL Server could not spawn FRunCM thread. Check the SQL Server error log and the Windows event logs for information about possible related problems. One lead I had was to change the SQL logon account from "Network Service" to "Local System". Unfortunately, that is resulting in the error message The Security ID Structure is Invalid [0x80070539] Any help either uninstalling or getting SQLExpress running would be fantastic.

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  • Fragmented Log files could be slowing down your database

    - by Fatherjack
    Something that is sometimes forgotten by a lot of DBAs is the fact that database log files get fragmented in the same way that you get fragmentation in a data file. The cause is very different but the effect is the same – too much effort reading and writing data. Data files get fragmented as data is changed through normal system activity, INSERTs, UPDATEs and DELETEs cause fragmentation and most experienced DBAs are monitoring their indexes for fragmentation and dealing with it accordingly. However, you don’t hear about so many working on their log files. How can a log file get fragmented? I’m glad you asked. When you create a database there are at least two files created on the disk storage; an mdf for the data and an ldf for the log file (you can also have ndf files for extra data storage but that’s off topic for now). It is wholly possible to have more than one log file but in most cases there is little point in creating more than one as the log file is written to in a ‘wrap-around’ method (more on that later). When a log file is created at the time that a database is created the file is actually sub divided into a number of virtual log files (VLFs). The number and size of these VLFs depends on the size chosen for the log file. VLFs are also created in the space added to a log file when a log file growth event takes place. Do you have your log files set to auto grow? Then you have potentially been introducing many VLFs into your log file. Let’s get to see how many VLFs we have in a brand new database. USE master GO CREATE DATABASE VLF_Test ON ( NAME = VLF_Test, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test.mdf', SIZE = 100, MAXSIZE = 500, FILEGROWTH = 50 ) LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5MB, MAXSIZE = 250MB, FILEGROWTH = 5MB ); go USE VLF_Test go DBCC LOGINFO; The results of this are firstly a new database is created with specified files sizes and the the DBCC LOGINFO results are returned to the script editor. The DBCC LOGINFO results have plenty of interesting information in them but lets first note there are 4 rows of information, this relates to the fact that 4 VLFs have been created in the log file. The values in the FileSize column are the sizes of each VLF in bytes, you will see that the last one to be created is slightly larger than the others. So, a 5MB log file has 4 VLFs of roughly 1.25 MB. Lets alter the CREATE DATABASE script to create a log file that’s a bit bigger and see what happens. Alter the code above so that the log file details are replaced by LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 1GB, MAXSIZE = 25GB, FILEGROWTH = 1GB ); With a bigger log file specified we get more VLFs What if we make it bigger again? LOG ON ( NAME = VLF_Test_Log, FILENAME = 'C:\Program Files\Microsoft SQL Server\MSSQL10.ROCK_2008\MSSQL\DATA\VLF_Test_log.ldf', SIZE = 5GB, MAXSIZE = 250GB, FILEGROWTH = 5GB ); This time we see more VLFs are created within our log file. We now have our 5GB log file comprised of 16 files of 320MB each. In fact these sizes fall into all the ranges that control the VLF creation criteria – what a coincidence! The rules that are followed when a log file is created or has it’s size increased are pretty basic. If the file growth is lower than 64MB then 4 VLFs are created If the growth is between 64MB and 1GB then 8 VLFs are created If the growth is greater than 1GB then 16 VLFs are created. Now the potential for chaos comes if the default values and settings for log file growth are used. By default a database log file gets a 1MB log file with unlimited growth in steps of 10%. The database we just created is 6 MB, let’s add some data and see what happens. USE vlf_test go -- we need somewhere to put the data so, a table is in order IF OBJECT_ID('A_Table') IS NOT NULL DROP TABLE A_Table go CREATE TABLE A_Table ( Col_A int IDENTITY, Col_B CHAR(8000) ) GO -- Let's check the state of the log file -- 4 VLFs found EXECUTE ('DBCC LOGINFO'); go -- We can go ahead and insert some data and then check the state of the log file again INSERT A_Table (col_b) SELECT TOP 500 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO -- insert 500 rows and we get 22 VLFs EXECUTE ('DBCC LOGINFO'); go -- Let's insert more rows INSERT A_Table (col_b) SELECT TOP 2000 REPLICATE('a',2000) FROM sys.columns AS sc, sys.columns AS sc2 GO 10 -- insert 2000 rows, in 10 batches and we suddenly have 107 VLFs EXECUTE ('DBCC LOGINFO'); Well, that escalated quickly! Our log file is split, internally, into 107 fragments after a few thousand inserts. The same happens with any logged transactions, I just chose to illustrate this with INSERTs. Having too many VLFs can cause performance degradation at times of database start up, log backup and log restore operations so it’s well worth keeping a check on this property. How do we prevent excessive VLF creation? Creating the database with larger files and also with larger growth steps and actively choosing to grow your databases rather than leaving it to the Auto Grow event can make sure that the growths are made with a size that is optimal. How do we resolve a situation of a database with too many VLFs? This process needs to be done when the database is under little or no stress so that you don’t affect system users. The steps are: BACKUP LOG YourDBName TO YourBackupDestinationOfChoice Shrink the log file to its smallest possible size DBCC SHRINKFILE(FileNameOfTLogHere, TRUNCATEONLY) * Re-size the log file to the size you want it to, taking in to account your expected needs for the coming months or year. ALTER DATABASE YourDBName MODIFY FILE ( NAME = FileNameOfTLogHere, SIZE = TheSizeYouWantItToBeIn_MB) * – If you don’t know the file name of your log file then run sp_helpfile while you are connected to the database that you want to work on and you will get the details you need. The resize step can take quite a while This is already detailed far better than I can explain it by Kimberley Tripp in her blog 8-Steps-to-better-Transaction-Log-throughput.aspx. The result of this will be a log file with a VLF count according to the bullet list above. Knowing when VLFs are being created By complete coincidence while I have been writing this blog (it’s been quite some time from it’s inception to going live) Jonathan Kehayias from SQLSkills.com has written a great article on how to track database file growth using Event Notifications and Service Broker. I strongly recommend taking a look at it as this is going to catch any sneaky auto grows that take place and let you know about them right away. Hassle free monitoring of VLFs If you are lucky or wise enough to be using SQL Monitor or another monitoring tool that let’s you write your own custom metrics then you can keep an eye on this very easily. There is a custom metric for VLFs (written by Stuart Ainsworth) already on the site and there are some others there are very useful so take a moment or two to look around while you are there. Resources MSDN – http://msdn.microsoft.com/en-us/library/ms179355(v=sql.105).aspx Kimberly Tripp from SQLSkills.com – http://www.sqlskills.com/BLOGS/KIMBERLY/post/8-Steps-to-better-Transaction-Log-throughput.aspx Thomas LaRock at Simple-Talk.com – http://www.simple-talk.com/sql/database-administration/monitoring-sql-server-virtual-log-file-fragmentation/ Disclosure I am a Friend of Red Gate. This means that I am more than likely to say good things about Red Gate DBA and Developer tools. No matter how awesome I make them sound, take the time to compare them with other products before you contact the Red Gate sales team to make your order.

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