IF you are browsing your error log and come across an error message stating that “1 transactions rolled forward in database ‘msdb'”, or “X transactions rolled back in database ‘msdb'” you might be a bit alarmed. You might also notice similar error messages for master, tempdb or user databases.
How can this be a good thing? Why are transactions being rolled back or rolled forward?
Here is a discovery that I made using the Database Health Monitor historic wait monitoring, on a server with slow storage where the backups were being written.
If you are seeing excessive waits on the PREEMPTIVE_OS_GETPROCADDRESS wait type and xp_create_subdir is the command with the wait, and this is occurring at the time your backups are being run, it is a symptom that the storage location for your backups is having I/O difficulties.
I noticed this on a server with an external USB 2.0 attached hard drive that was being used for backups, and on a second server with a USB 3.0 external hard drive. When the backups run, there was a wait for the process to attempt to see if the backup directory exists, and to create it if it did not.
Read More »PREEMPTIVE_OS_GETPROCADDRESS and xp_create_subdir
The Quick Scan report in Database Health Monitor detects when you are performing SQL Server backups without compression, when the compression option is available. This applies to Full backups, Transaction log backups and Differential backups.
Not using compressed backups? Why not?
There are a couple minor drawbacks, the compressed backups take more CPU, not much more, but a tiny bit more. Also the compressed backups don’t compress very much when your database is using Transparent Data Encryption (TDE).
Over the last year, I have published many videos to YouTube with Free SQL Server Training. You can find these on my YouTube Channel at… Read More »Free SQL Server Training Videos
If you have more memory than your database and applications on the SQL Server will ever use than this is not a problem, but when you run into memory constraints this setting is much more important.
SQL Server attempts to use as much memory as possible, and when there is no more memory available, SQL Server will use much more I/O due to data and index pages having to be read from disk more often. This works great for SQL Server, but what happens is that SQL Server will take almost all the memory leaving very little for the operating system processes or other applications that are running.
The default for this setting is 2147483647 which is probably more memory that your server has, which effectively tells SQL Server to take as much memory as it wants to.
In SQL Server there is a special connection that can be used to connect to the database, the remote Dedicated Admin Connection or (DAC). This… Read More »SQL Server – Dedicated Admin Connection (remote DAC)
Here are the slides for my presentation at SQL Saturday, at Las Vegas today. Download the presentation here CorruptionPresentation.pdf
As part of the Database Health Monitor version 2.1 release there were many new report includes, one of those was the backup status report. A… Read More »Featured Report: Backup Status Report
I have just released version 2.1 of Database Health Monitor, this release involved 2 months of development since version 2.0 was released in July. People… Read More »Database Health Monitor version 2.1 Just Released
This Saturday, September 12th, 2015 I will be presenting at SQL Saturday Las Vegas. My presentation is on Database Corruption, here are the details.
Duration: 60 minutes
Track: Enterprise Database Administration & Deployment
You are working along month after month with no problems in your database. Suddenly someone reports that their query won’t run. They get an error stating “SQL Server detected a logical consistency-based I/O error“, or something even scarier. Do you know what to do now? We will walk through 3 or 4 actual corrupt databases exploring ways to go about finding and fixing the corruption. More importantly we will explore how to prevent further data loss at the time corruption occurs. Learn what things you should do to protect yourself when corruption strikes. Learn what to avoid that will make things worse. You will leave with a checklist of steps to take when you encounter corruption. By the end of this session you will be ready to take on corruption, one database at a time.
The presentation is scheduled for 11:00 am to Noon in room 2767 at the College of Southern Nevada campus in Vegas.