SQL Server parallel processing

SQL Server parallel processing

SQL Server provides parallel queries to optimize query execution and index operations for computers that have more than one microprocessor (CPU). Because SQL Server can perform a query or index operation in parallel by using several operating system threads, the operation can be completed quickly and efficiently

How Parallel Execution Works on SQL Server

SQL Server looks for queries or index operations that might benefit from parallel execution.For these queries, SQL Server inserts exchange operators into the query execution plan to prepare the query for parallel execution. An exchange operator is an operator in a query execution plan that provides process management, data redistribution, and flow control.

The exchange operator includes the Distribute Streams, Repartition Streams, and Gather Streams logical operators as subtypes, one or more of which can appear in the Showplan output of a query plan for a parallel query.

After exchange operators are inserted, the result is a parallel-query execution plan. A parallel-query execution plan can use more than one thread.The actual number of threads used by a parallel query is determined at query plan execution initialization and is determined by the complexity of the plan and the degree of parallelism. Degree of parallelism determines the maximum number of CPUs that are being used.

Degree of Parallelism in SQL Server

SQL Server automatically detects the best degree of parallelism for each instance of a parallel query execution or index data definition language (DDL) operation. It does this based on the following criteria:

Whether SQL Server is running on a computer that has more than one microprocessor or CPU, such as a symmetric multiprocessing computer (SMP).

Whether sufficient threads are available.

The type of query or index operation executed.

Whether there are a sufficient number of rows to process.

Whether current distribution statistics are available.

Tips for rendering Overlays on Google map

If there are more than thousands of Overlays (Markers, Polylines and Polygons) to be displayed on a Google map it starts to get slow due to browser javascript performance and network throughput limits. To maintain high performance, you can use the following techniques

• Only the overlays that are to be shown in the current map are sent to the browser from backend
• If the map is panned or zoomed, only the differences to the visible set are sent
• Polylines and Polygons are clipped to the visible rectangle so that only the visible parts of the lines are sent
• At lower zoom levels

Cluster markers are used in place of actual markers
Polylines and Polygons are simplified to reduce the number of points

• At even lower zoom levels, 256 x 256 tile images are generated with the marker images, polyline sand polygons drawn on them.
• These tiles are cached on disk once generated.

Top 10 Programming Languages 2010

Through the latest statistics by TIOBE index here is the table that show the ranking of the top 20 popular languages :




If you want to make a lot of money, but probably also work on very intense high-pressure projects where risk is often involved—as in a lot can go wrong—learn Objective-C. Objective-C borrows from Smalltalk and the C language, and it influenced the creation of Java. Objective-C is used primarily on Apple's Mac OS X and iOS. With the wild popularity of Apple's iPhone, iPod Touch and iPad, there are simply not enough Objective-C developers out there to meet the needs of users hungry for more apps for these devices. Objective-C ranked No. 9 on the most-recent TIOBE survey, but that is up from being No. 45 in the survey in June of 2009.

Google Moon and Mars

Hi Guys,

Here we go Moon and Mars
http://www.google.com/moon/
http://www.google.com/mars/

Google Moon is a service similar to Google Maps that shows satellite images of the moon.The landing site of each of the Apollo missions is shown on the satellite image,providing more information on each mission as the user zooms in.

Page Speed

Google map api v3 support over https

It is great news from Google map api development team. We can access the Maps JS api over HTTS, allowing us to utilize oue secure private data.

To load the Gmaps JS API v3 over HTTPS from following URl:

https://maps-api-ssl.google.com/maps/api/js?v=3&sensor=false

query string V is Googlemap api version and sensor is GPS locator to determine the user's location.