Wednesday, September 21, 2011

Differences Between Dedicated Servers, Shared Servers, and Database Resident Connection Pooling


Oracle  creates  server  processes  to  handle  the requests  of  user  processes connected  to  an  instance. A  server process can be either a dedicated server process, where one server process services only one user process, or if  our database server is configured for shared server, it can be a shared server process, where a server process can service multiple user processes . Let's have a look

Dedicated Servers:  
1.)  When a client request is received, a new server process and a session are created for the client.
2.)  Releasing database resources involves terminating the session and server process
3.)  Memory requirement is proportional to the number of server processes and sessions. There is one server and one session for each client.
4.)  Session memory is allocated from the PGA.


Shared Servers : 
1.) When the first request is received  from  a client, the  Dispatcher  process places this request on a common  queue. The request is picked up by an available shared server process. The Dispatcher process then manages the communication between the client and the shared server process.
2.) Releasing database resources involves terminating the session
3.) Memory requirement is proportional to the sum of the shared servers and sessions. There is one session for each client.
4.) Session memory is allocated from the SGA.


Database Resident Connection Pooling : 
1.)  When the first request is received from a client, the Connection Broker picks an available pooled server and hands off the client connection to the pooled server.  If no pooled servers are available, the Connection Broker creates one.If the pool has reached its maximum size, the client request is placed onthe wait queue until a pooled server is available.
2.)  Releasing database resources involves releasing the pooled server to the pool.
3.) Memory requirement is proportional to the number of pooled servers and their sessions.There is one session for each pooled server.
4.) Session memory is allocated from the PGA.


Example of Memory Usage for Dedicated Server, Shared Server, and Database Resident Connection Pooling :
Consider an application in which the memory required for each session is 400 KB and the memory required for each server process is 4 MB. The pool size is 100 and the number of shared servers used is 100.If there are 5000 client connections, the memory used by each configuration is as  follows:


Dedicated Server 
Memory used = 5000 X (400 KB + 4 MB) = 22 GB


Shared Server 
Memory used = 5000 X 400 KB + 100 X 4 MB = 2.5 GB
Out of the 2.5 GB, 2 GB is allocated from the SGA.


Database Resident Connection Pooling 
Memory used = 100 X (400 KB + 4 MB) + (5000 X 35KB)= 615 MB
where 35KB is used for others operation




Enjoy    :-)


20 comments:

Anonymous said...

What a stuff of un-ambiguity and preserveness of valuable know-how regarding unpredicted emotions.


Here is my web-site - Chip Satış (http://www.chipsitem.com/)

Ronald Nichols said...

Great definition between dedicated hosting server, shared server and database resident connection pooling. I've learned a lot.

Villian Max said...

Wow!!! Honestly speaking you are really a great writer. What I required I got it. Thank you so much.
Dedicated Server

Anonymous said...

I think in Shared Server Mode
Memory used = 5000 X 400 KB + (5000:100) X 4 MB

KIRTAN KHATSURIYA said...

Awesome bro..
you did write exactly what i want.
no less and no more.
appreciate your work.
thankss..

Xtreme Dedi said...

Thanks for sharing great full knowledge about dedicated servers.You can also find best Dedicated Servers in USA

Rachna Kataria said...

Amazing Blog! You share really very useful information about Dedicated Servers. Thanks for sharing such good information with us.

Dedicated Servers said...

Perfectly describe Dedicated Servers. And I believe dedicated server is far better than virtual.

Villian Max said...

Excellent blog, you gave very useful information about dedicated servers in it. Thanks and keep posting.

Abid Bhatti said...

Awesome this is really good post dedicated servers could also be a computer that manages printer resources.

Prekshya Marlons said...

One of the best information about this topic you have shared here and this is what i was looking for, Great job. Top web hosting companies

Sharif Mustakim said...

Thank you so much for taking the time to share such a nice information. I'll definitely add this great post in my article section.
dedicated server

Sharif Mustakim said...

It is my first time I visit here. I found so many entertaining stuff in your blog, especially its discussion. From the tons of comments on your articles, I guess I am not the only one having all the enjoyment here! Keep up the excellent work.
dedicated server

Gaurav solanki said...

Thanks for such wonderful information on different servers! It has really helped me to find out the difference between dedicated server and shared server. Great post!!

Manoj Kadam said...

Thanks for such wonderful information on different servers! It has really helped me to find out the difference between dedicated server and shared server. Great post!!

Sumi Akter said...

Get Blazing Fast Asia Optimized Server For Affordable Price Here - THESTACK.NET

Blogger said...

Bluehost is definitely the best hosting company with plans for any hosting requirments.

anz globalsoft said...

nice article, thank you very much for sharinng such a good content.
WORDPRESS HOSTING SERVICES IN PAKISTAN
SSL CERTIFICATES

anz globalsoft said...

this is a very good article, thank you very much for sharing such a good content.
WORDPRESS HOSTING SERVICES IN PAKISTAN
SSL CERTIFICATES

anz globalsoft said...

WORDPRESS HOSTING SERVICES IN PAKISTAN
SSL CERTIFICATES