When data in a database is read or modified, the database engine uses special types of controls, called locks, to maintain integrity in the database. Locks basically work by making sure database records involved in a transaction cannot be modified by other transactions until the first transaction has committed, ensuring database consistency.
When designing database applications, you should keep in mind the different types of locks that will be issued, and the different levels of isolation your transactions will occur. Typically, the SQL Server defaults work fine for what you are trying to accomplish. However, there will be times when it is advantageous to manually make hints to how locks are issued on your tables in your SQL statements.
Feb 15, 2011
Use NOLOCK and READPAST table hints in SQL Server for speed up query
Feb 8, 2011
Tips to Speed up SQL Server database queries
by Tim Chapman, TechRepublic
Dec 25, 2010
The Current Disadvantages of Merging a Place With a Page on Facebook
| By Josh Constine |
The official guide to Place for advertisers explains that users who claim Places and are also an admin of a similar Page may be prompted to merge their Place and Page. Facebook recommends merging if a business has only one physical location and only one Page. The guide says, “you’ll be able to manage your business centrally on Facebook”, and Likes, content, custom tabs, and ads directing to the Page will remain intact.
An important reason not to merge is that users may be confused by the change in user interface: a merged Places Page does not display tabs the way a traditional Page does. (However, it’s possible will move the tabs under the profile photo like they are on the recently redesigned user profiles – though Facebook hasn’t said that.) Instead, it uses a navigation panel beneath the Page’s picture. Users won’t see a panel of friends who Like that Places Page or previews of uploaded photos and videos, plus the option to suggest the Places Page to friends is dropped to the very bottom of the left sidebar.
Engaging with merged Places Pages is more difficult as well. The default landing tab is the Profile, which shows the Places address, a map, hours, and a description. Even if users have Liked the Places Page, they still see this tab upon visiting, and have to navigate to the Wall via the navigation panel in order to share their opinions or publish content. This is much different than traditional Pages, where those who’ve clicked Like can immediately post to the wall upon visiting. If getting users to communicate with each other and foster a sense of community is a business’ goal, the traditional Page is a better fit because those who’ve clicked Like see the Wall and publisher first.
While this navigation format is similar to the newly redesigned user profile, users are accustomed to seeing tab applications along the top of a Page, not running down the left sidebar.
Another serious deficiency of merged Places Pages is that admins cannot change the landing tab. Many businesses spend a lot of money or time creating custom tab applications or outsourcing this job to a Page management company. Being unable to show these apps to those who haven’t Liked your merged Places Page can hurt Page growth. Therefore, merged Places Pages miss out on much of the opportunity to condition access to tab app contests or content on a user Liking the Page.
It’s possible that Facebook will address these issues in upcoming product updates, but that’s the way it works for now.
Facebook says a “A solution for linking multiple Places to a single Facebook Page will become available in the future”, but it first needs to make this a more attractive option. The ability to set a landing tab promotes Page growth, which is important to Facebook as well as admins.
Facebook Now Allows Merged Places Pages to Unmerge
| By Josh Constine |
Merged Place Pages are unable to set a default landing tab, frustrating admins who use custom tabs but had merged without knowing the consequences. The new unmerge option restores all the functionality of the separate entities.
Admins of merged Place Pages now see an “Unmerge all merged Places” button in the bottom left of their Page. When clicked, admins are shown the following confirmation message:
“Once you confirm this request, the format of this Page will be reverted to the previous format and location information will be removed. The Places that you merged will be restored as separate claimed Places that you also still own and must continue to manage.”
[Thanks to Kim Bui of KPCC Los Angeles for the tip]
Nov 18, 2010
What is svchost.exe service And Why Is It Running on Windows?
So What Is It?
According to Microsoft: “svchost.exe is a generic host process name for services that run from dynamic-link libraries”. Could we have that in english please?
Some time ago, Microsoft started moving all of the functionality from internal Windows services into .dll files instead of .exe files. From a programming perspective this makes more sense for reusability… but the problem is that you can’t launch a .dll file directly from Windows, it has to be loaded up from a running executable (.exe). Thus the svchost.exe process was born.
Why Are There So Many svchost.exes Running?
If you’ve ever taken a look at the Services section in control panel you might notice that there are a Lot of services required by Windows. If every single service ran under a single svchost.exe instance, a failure in one might bring down all of Windows… so they are separated out.
Those services are organized into logical groups, and then a single svchost.exe instance is created for each group. For instance, one svchost.exe instance runs the 3 services related to the firewall. Another svchost.exe instance might run all the services related to the user interface, and so on.
So What Can I Do About It?
You can trim down unneeded services by disabling or stopping the services that don’t absolutely need to be running. Additionally, if you are noticing very heavy CPU usage on a single svchost.exe instance you can restart the services running under that instance.
The biggest problem is identifying what services are being run on a particular svchost.exe instance… we’ll cover that below.
If you are curious what we’re talking about, just open up Task Manager and check the “Show processes from all users” box: