“Attempt to read or write protected memory” error from SSMS for System.Data

I just spent a couple of hours fruitlessly trying to solve a problem and thought I’d blog the solution in case anyone else hits the issue.

A few months back I got a new laptop and installed SQL Server 2014 on it and everything worked fine. A few weeks ago I installed SQL Server 2008 R2, SQL Server 2012, and Visual Studio 2013. After that, any time I tried to use the Dedicated Admin Connection (DAC) through SSMS, I got this error:


I did some research online and couldn’t find any solutions that worked. So I tried repairing the installation, installing 2014 SP1 CU2 (latest build at time of writing), and a bunch of other things – to no avail. I was just about to give up and post a request for help when I thought I’d do one more search online.

When I did that, I noticed that all the solutions I’d tried had revolved around the assembly name in the error being something to do with SQL Server. In my case, it was System.Data, which is a .NET assembly. I added that into my search and found a bunch of new hits. Lo and behold, buried in the comments on a Stack Overflow question, I found the solution.

Turns out the problem was because of an upgraded .NET version, and the solution was to run the following from a command line and then reboot:

netsh winsock reset

And after that SSMS worked perfectly.

Hope this post helps others find the answer quickly in future!

Limiting error log file size in SQL Server 2012

It’s quite well known that you can optimize error log file management using SSMS to change the maximum number of error log files to 99 and running sp_cycle_errorlog every day at midnight (see this post on my old SQL Server Magazine blog for graphics). This works in all current versions of SQL Server.

One thing that hasn’t been possible before is setting the maximum size of individual SQL Server error logs before SQL Server triggers cycling to a new error log. Well it turns out that in SQL Server 2012 you can!

While in my post-con workshop at SQL Intersection in Las Vegas last week, Jan Kåre Lokna (a former Immersion Event attendee from Norway) discussed some code he’s been experimenting with and I just heard from him that he got it to work.

The following code will set the maximum size of each error log file to 5MB on a SQL Server 2012 instance:

USE [master];

EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE',
    N'ErrorLogSizeInKb', REG_DWORD, 5120;

I’ve tested this on SQL Server 2008 R2 and it does not work there, so the registry key must be new for SQL Server 2012. This is really useful to protect against gigantic error log files caused by repeated crash dumps, for instance when messing around with DBCC WRITEPAGE :-)

[Edit: 10/23/15] Also, for SQL Server 2014 the registry keys have changed again:

USE [master];
-- Limit size of each file
EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE',
N'SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQLServer',
N'ErrorLogSizeInKb', REG_DWORD, 1024;

-- Number of ErrorLog Files
EXEC xp_instance_regwrite N'HKEY_LOCAL_MACHINE',
N'SOFTWARE\Microsoft\Microsoft SQL Server\MSSQL12.MSSQLSERVER\MSSQLServer',
N'NumErrorLogs', REG_DWORD, 8;

Note: I’ve had anecdotal reports that on SQL Server 2014, the SQL Server 2012 method is the only one that works. Please experiment and see which works in your situation. I imagine the difference may be due to fresh-install vs. upgraded-in-place.

You can read a more in-depth description on Jan’s blog here.

Cool free tool to parse and analyze SQLIO results

During every one of our Immersion Events, we designate Thursday evening as 'open mic' night where anyone can do a 15-minute presentation on anything they want (to do with SQL Server) to the class. We usually have 4 or 5 people who entertain us with interesting talks, and our recent classes in Chicago were no different.

One of the talks really impressed me. David Klee (b|t) demonstrated an automated analysis tool he's written for SQLIO result file parsing to save him time. He mentioned he was going to put it online and I encouraged him to do so as I could see the benefit to many people out there of not having to write their own analysis tools/spreadsheets.

You can get to David's free analysis site at http://tools.davidklee.net/sqlio.aspx. Clicking on the link at bottom right allows you to upload a SQLIO results text file. Once you've clicked ANALYZE, select the option to output the results to a spreadsheet and one will be automatically generated for you. If you look in the Analysis pane of the spreadsheet, you'll see something like below (using David's supplied example SQLIO output).

Very cool stuff – thanks David!