2010 January - Writing Something

Archive for January 2010

Sql Server Analysis Services Storage Options

January 27th, 2010 — 1:56am

Real time – ROLAP

You are in the closest position to real information. (Every action affects this storage) But your reports will be slower than the other options. All your information is in OLTP database. We can say you are using analysis services for declaration.

If your database is very very big, MOLAP is undesirable, so you need to choose ROLAP.

Summary

Slowest Performance
Zero Latency
No duplicate data (less disk usage)

Real Time HOLAP

Your information is stored in relational architecture. But the aggregations are stored in multidimensional format. Whenever a change occurs server recalculates the aggregations. On calculation time analysis services switches to ROLAP Mode!

This option is best if you want the latest data and your OLTP source changes rarely.

Best processing time (processing time is not the time that you preview a report!)
Zero Latency
No duplicate data (less disk usage)

MOLAP

Provides and optimized multidimensional storage, both data and aggregations stored in MOLAP architecture. MOLAP gets all data from the OLTP source but compresses and does not store null data. MOLAP has fastest query result time. You need more disk space in these options. But MOLAP has the best performance.

In Analysis Services we have 5 MOLAP options; Low Latency MOLAP, Medium Latency MOLAP, Automatic MOLAP, Scheduled MOLAP and MOLAP

Low Latency MOLAP

This option has a cache. But if a change occurs in a current data server switches to ROLAP. And at least silence 10 seconds is required before updating cache. Processing occurs after 30 minutes from the first notification. Low latency MOLAP is used for frequently updated data sources when performance is more important than providing latest data.

Medium Latency MOLAP

This option works like Low latency MOLAP. The difference is Medium Latency MOLAP processes cube after 4 hours from the first notification.

Automatic MOLAP

Automatic MOLAP never switches to ROLAP. Always keeps the cache. But a 10 second silence time occurs when new cache comes. Processing occurs after 2 hours of change notification. Reports do not return the most recent data while the new cache is being built and processed.

Scheduled MOLAP

Scheduled MOLAP option does not listen server for changes. It processes automatically every 24 hours.

MOLAP

This option provides the best performance. Server does not check for any changes. You need to manually process your cube. If your reports does not need the latest data but best performance you must chose this option. If you have enough conditions (a big disk, a good processor which can calculate before you die :) ) it is very good to calculate all aggregations.
Read this article for more information. (http://msdn.microsoft.com/en-us/library/ms175646.aspx)

Comment » | Business Inteligence

Doğanın Kötü Gün Dostları

January 25th, 2010 — 2:01am

Havaların kötü olduğu zamanlarda doğa yanlız ve boynu bükük kalıyor. Gerçe kötü demeyelim soğuk havalarda diyelim. Hava neden kötü olsun hava hep iyi :) Soğuk olması bizim için zor diye kötü olduğu düşünülemez :) Doğa bu durumundan rahatsız değildir heralde?

Biz bu haftasonu biraz daha sert bir etkinlik yapmak istedik. Hakan, Akın, İbrahim ve benden oluşan 4 kişilik bir ekiple Güvenli köyünden Yeni gürleye gitmek istedik.

Ancak araç Güvenli’ye ulaşamayınca Adliye’den başlamak zorunda kaldık. Güvenli’ye 5km uzakta başladık rotaya. 500 metreden 1000 civarına geldiğimizde planladığımız rotayı 3 gece kalsak anca bitirebileceğimizi anladık :) Kar hızımızı baya kesti. Zaman zaman belimize kadar gömülebilecek yerlerde bulduk ama genelde dizimize kadar batarak yürüdük.

3 gece kalabilecek durumda olmadığımızdan Fevziye’ye varıp öyle bitirelim diye düşündük. Malum Pazartesi sabahı iş var :) Fakat oda olmadı Fevziye’de uzak kaldı. Minibüsün de bize ulaşımını düşünüp Hamidiye köyüne inmeye karar verdik. Saat 5 gibi Hamidiye köyü kahvesinde zeytinyağlı sarmalarımızı yiyerek aracı beklemeye başladık.

Araba bize gelemedi yanlız. Bizde Katırlı köyünü aşıp arabaya gittik. Eve dönüş sorunsuzdu ama bu katırlı köyünü aşıp arabaya gittik kısmı sürpriz bi 6-7 km verdi bize :)

Uzun zamandır böyle keyifli bir faaliyet yapmamıştım. Bir sonrakini iple çekiyorum…

Comment » | Anı

Some Tips to Improve Your Web Sites Performance

January 18th, 2010 — 7:16am

We all wish quickly loaded web sites. But we sometimes miss out or do not know the easy implementations that can affect performance. There are realy great articles about performance. Once is the yahoo’s famous performance rules (http://developer.yahoo.com/performance/rules.html) as we all know. And another good resource is the google’s “Let’s make the web faster” project’s speed articles. (http://code.google.com/speed/articles) Definately you should read more about performance subject. But this article could be a fast start.

Add Expires Header

The biggest enemy of the performance is unnecessary HTTP requests. If an image is already sent to the client or a JavaScript file, mustn’t be requested again. If we add expires header to unchanging files, browser will not request the same file again. We gain performance and also we will save bandwidth. These files like logo images, base JavaScript files that will not change for the life of the site. Give a hundred years :) forward expire time to them.

The thing you will do is really simple if your server is apache. Add this code to your .htaccess file.

<FilesMatch “\.(ico|pdf|flv|jpg|jpeg|png|gif|js|css|swf)$”>
Header set Expires “Thu, 15 Apr 2099 20:00:00 GMT”
</FilesMatch>

Read more apache speed tips. (http://www.askapache.com/htaccess/apache-speed-expires.html)

Compress your JavaScript

We realy use very much JavaScript code. And we like it don’t we? :) I use javascripts to make my page more user friendly. Sometimes our scripts can be untidy. Keep them clean and compressed. Because every chacter is a byte, even it is a space. There are online tools to compress javascripts. One of them is javascriptcompressor.com.

Before I finish this paragraph I would like to add another advice. Put your JavaScript’s just before body tag.

This is a good practice because by doing this, browser first loads your html and images, then loads JavaScripts. And so your visitor sees the page earlier. JavaScript’s are not the first items that needed to show your design.

Compress your CSS

Every chacter is a byte, even it is a space. So CSS files should aslo be compressed. My favorite online tool is csscompressor.com.

Use page speed plugin

Page Speed is a plugin which is integrated in firebug. It analyses the page and advises you. The best thing page speed does is compressing images. Under the optimize images tab you will see all the images that need compression and the compressed images links. Check this link (http://code.google.com/intl/tr-TR/speed/page-speed/) for more about page speed.

Comment » | Something

Yudosk’un Abantı İşgali

January 17th, 2010 — 1:15pm

Bu Pazar göl kenarında mangallı bir etkinlik yaptık. Benim katıldığım en kalabalık etkinlikti. 90 kişi vardık.

abant

Kimimiz göl kenarında yürüdü kimimiz Hakan Efe’nin pesine düştü, kimimizde sıcak çay ile göl kenarındaki soğuk kafelerden birinde oturdu. Ben sıcak bişeyler içip soğuk soğuk oturanlardandım karda yürümenin tadını alamadım içimde de kaldı bı dahakine artık. Gerçi yuruyenlerde daha cok kar olsa daha mutlu olurdu heralde. (Yeterince varmış sonradan öğrendim :) )

Yol uzak olunca yürüyüşte kısaydı. Ama mangal masaları uzundu :) hem kaptan hem asçı gursel abi hepimizi doyurdu… Ellerine saglık. Lezzet maksimumdu ama Hava biraz daha ılık olsa daha iyi olacaktı mangal keyfi … Yürümeyen ve kısa yürüyenler olarak mangal gıdalarimizi tükettikten sonra üşümeye başladık. Ve 3 otobüs gelmenin avantajını kullanarak bir otobüsü doldurup biraz erken başladık dönüş yolculuğuna …

Benim abant maceram bu kadar hakan efenin pesinden gidenlerin maceraları daha esaslı olacaktır …

Comment » | Anı