Dedicated server/shared server

Hi everyone,
can you Explain me about the shared server/dedicated server mode .
THANKS IN ADVANCE

think of the oracle server process as a genie- the magical being from the story of Aladdin-because your wish for a oracle data is the server process command-
dedicated server(one genie one master):-_in this setup every single user connecting to oracle will have a personal genie handling data retrieval from disk in to buffer cache. if there are 120 users connecting to oracle there will also be 120 genies out there grabbing data from disk and putting it in the buffer cache for those user. this architectural setup means that every user gets his or her data retrieval requests acted upon immediately. it also means there will be additional memory and cpu overhead on the mechine running the oracle database.
shared server:-(one genie one master):-* in this setup there is a small pool of server process running in oracle that supports data retieval requests for a large number of users. several users are served by one server process.if there are 120 users connecting to oracle there will be only 1 genie out there for grabbing data from disk and putting it in the buffer cache for those user.

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SAP db upgrade to Oracle 10G 64 bit - Dedicated or Shared Server ?

We current run 32bit servers ( approx 150 users ) and plan to migrate to ECC 6.0 on 64bit bit server. Question about upgrade from Oracle 9.2.0.8 32bit to 10.2.0.4 64 bit . Database upgrade Oracle 64 bit should be Dedicated or Shared Server? 
My understanding ( limited), is Oracle 64bit dedicated server connection has the dedicated resource so whether or not a user is doing work the connection remains allocated to that user. So for example, in our case a small Windows "shop" will needs around 2MB of kernel space. So 150 threads, for 150 dedicated server connections, approx 150 x 2MB RAM. Correct ? 
Whereas Shared server the user connection is shared, that is user is connecting by dispatchers and when a user is idle his resource can be used by other users, thus lessen the load on system. So in this case maybe 5 dispatcher processes and 30 shared server processes to service the 150 sessions of the 150 users which seems very effective to me . My main concern however is with some of the Finance people who get problems with huge COPA and SIS reports now which is why we are moving to 64bit OS/DB/SAP 
Question is which does SAP ECC 6.0 support ( or recommend ) Oracle 64 bit Dedicated or Shared Server db migration ?

> Question is which does SAP ECC 6.0 support ( or recommend ) Oracle 64 bit Dedicated or Shared Server db migration ?
Never heard that anyone uses shared Server Setup with SAP.
With SAP, it is NOT the user having a DB connection.
It is the workprocess, and it is keeping it even if all users are idle.
You allways have dedicated Oracle processes for SAP Workprocesses.
The rather old note 70197 states, that Oracle MTS (multi threaded server)
allowed, but you are on your own to configure it and there are some pitfalls.
Volker

Dedicated or shared server configuration

Hi all,
Good day...We have a 10204 rac db running on a linux server. Our concurrent connection are more than 1000..Is that good to have a shared server configuration or we can continue with dedicated server configuration...
thanks,
baskar.l

baskar.l wrote:
Good day...We have a 10204 rac db running on a linux server. Our concurrent connection are more than 1000..Is that good to have a shared server configuration or we can continue with dedicated server configuration...You make the question sound to exclusive - "shared OR dedicated".
In reality, all Oracle databases are capable of supporting both shared AND dedicated connections at the same time.
So perhaps the question becomes:
Based on the workload (typical transaction style) of the connections, how many shared and how many dedicated connections are required?
To answer that YOU need to understand your workload.

Killing users Dedicated server / Shared Server

Hi,
I have a Web Applications that connects to our Oracle database and I can see a lot of users
stuck in the server and I have to manually kill these users.
To do this I´ve set a idle time to the conections , and using this script I´m able to kill these users :
sqlplus system/xxxxxx@instance <<EOF
spool $tmpfile
select p.spid from v\$process p,v\$session s
where s.paddr=p.addr
and s.status='SNIPED';
spool off
EOF
for x in `cat $tmpfile | grep "^[0123456789]"`
do
kill -9 $x
done
rm $tmpfile
I´ve also configured dead conections detection.
But unfortunatelly This machine has limited resources and the number of users will grow a lot in near future. So my only option is to change the database to shared server. In Shared server I cannot use my script anymore, because it kills all the connected users of that shared server , and dead connections detections is not working very well too ...
Anybody have a similar problem ? What could be done to clear the users that have already disconected from application and still use shared server mode ?
Whn users Log off the application it works ok, but sometimes the user closes the browser or we have blue screen in windows, etc and the conection remains forever
Thank you in advance,

Really think this should be application issues rather than database issues. Application or application server should have a way to handle idle sessions. It's not a clean way to kill session in the background like that.
In my environment, after developers changed application we don't have this problem any more.

Need to create a Database in Shared Serve Mode

Hi,
Please help me in Creating a Manual Database in Shared Server Mode. (I am a Student and It is a Learning Process).
I am able to Create Database (Without DBCA) in Dedicated Mode and I have no doubts in that.
What are the parameters i need to specify
Please post me Helpful Links

Poorna Prakash wrote:
Hi,
Please help me in Creating a Manual Database in Shared Server Mode. (I am a Student and It is a Learning Process).
I am able to Create Database (Without DBCA) in Dedicated Mode and I have no doubts in that.
What are the parameters i need to specify
Please post me Helpful LinksYOu need to understand that ... as far as the database is concerned ... it's not an either/or situation between dedicated and shared server. Setting shared server parameter like DISPATCHERS simply allows the database to handle shared server connections. But it is up to the client to specify which method it wants, and the database will always allow dedicated server connections.

Shared server error in RAC ?

_I changed my RAC database from dedicated to shared server . Then I changed client tnsnames.ora to meet shared server and tried to connect . It worked fine and I could do my job as normal.
But when I connected as sysdba and used (select server from v$session) to verify , there were 1 session NONE and no session SHARED . I tried to connect 5 more session from clients and there were 5 more NONE .
Then I used (select circuit,dispatcher from v$circuit) and there were exact 6 circuits.
_Is this an error in RAC ? Did I fail to convert from dedicated to shared server ?Please help.
My system : RAC10g , OracleEnterpriseLinux5

_This is my tnsnames.ora in client
HTI =
(DESCRIPTION =
(LOAD_BALANCE=yes)
(ADDRESS = (PROTOCOL = TCP)(HOST = dataht1-vip)(PORT = 1521))
(ADDRESS = (PROTOCOL = TCP)(HOST = dataht2-vip)(PORT = 1521))
(CONNECT_DATA =
(SERVER = SHARED)
(SERVICE_NAME = HTI)
_Clients can connect and work as normal with this tnsnames.ora . But when I try to find out how many sessions are in SHARED mode using (select server from v$session) there is 0 SHARED session althought there are about 20 client connections with the tnsnames.ora . There are 2 type of session when I use (select server from v$session) : NONE and DEDICATED . The more clients connect with the tnsnames , the more NONE sessions are created and no more DEDICATED sessions are created.
_I really don't understand what NONE means !

Dedicated or Shared Sessions?

I have a 10g SE1 + ASM running in Windows 2003 ES with 4GB RAM with /3GB switch and 7TB JBOD storage. Our custom data mining applications access this database from a grid of 15 servers. Application architecture uses a mixture of hibernate, roll-your-own connection pooling in Java, and daemons with dedicated sessions. In all, we typically have 200 sessions but only 3 to 9 are active at any given moment. Individual queries and transactions range from sub-second to 3 hours in duration.
I’ve run the system with MTS and in dedicated server mode; it runs either way. I have never tried tweaking multiple shared_servers, dispatchers or circuits.
Right now it seems to run fine with 200 dedicated sessions, but it does gobble up a lot of unused PGA memory for the inactive sessions.
In our situation, what is the best configuration, MTS, or shared, or dedicated, and why?

Mark, I think that physically a shared server process is no different than a dedicated server process in Oracle on Windows - both are threads in the oracle.exe process image.
The only real difference is that one deals directly with the client, and the other with a virtual circuit.
This then raises the question about the PGA and UGA. As the thread runs in the oracle.exe space, it has direct access to, and uses, the data segment (DS) of oracle. The PGA is likely a dynamic memory allocation - so too the UGA for a dedicated thread, while a shared thread will use the SGA instead (for the UGA).
Now assuming that my speculation is not far of, there are very little overheads between dedicated and shared server threads on Oracle in Windows - except for the dedicated servers being more and thus more PGAs given the nature of these threads versus shared server threads.
This is unlike Unix where there is a large physical difference as each process (dedicated or shared) has data segment and code segment. The resource footprint for a process is a lot bigger.
A concern of mine... Windows is excellent at running threads.. it really strains running lots of physical processes (unlike Unix/Linux). But as threads share the same code and data segments, a single thread running into a severe bug can potentially corrupt the entire physical process image, crashing all other threads in it. At least, this has been my experience doing Windows server development.
Would be nice to read a technical paper on just how Oracle implements their shared and dedicated server models on the Win32 API.

Problem switching dedicated to shared

Hello,
I'm trying to switch from DEDICATED to SHARED server mode. I'm running oracle ee r2(8.1.6) on redhat 6.2. I have some oracle documentation that says to add the following lines to the end of init.ora
mts_dispatchers = "(protocol=TCP)(DISP=1)(mul=OFF)(pool=OFF)"
mts_servers = 1
mts_max_servers = 20
I shutdown oracle to make the changes to init.ora and then restarted. Oracle comes up fine, but when I check server in v$session I get all DEDICATED. Please help.
Thanks,
David

<BLOCKQUOTE>quote:<HR>Originally posted by davidxm:
Hello,
I'm trying to switch from DEDICATED to SHARED server mode. I'm running oracle ee r2(8.1.6) on redhat 6.2. I have some oracle documentation that says to add the following lines to the end of init.ora
mts_dispatchers = "(protocol=TCP)(DISP=1)(mul=OFF)(pool=OFF)"
mts_servers = 1
mts_max_servers = 20
I shutdown oracle to make the changes to init.ora and then restarted. Oracle comes up fine, but when I check server in v$session I get all DEDICATED. Please help.
Thanks,
David<HR></BLOCKQUOTE>
I had the same problem. I'm following through the Oracle 8i for Linux Starter Kit, by Steve Bobrowski.
After editing the initoralin.ora file and adding the mts_ parameters, I tried
sqlplus system/manager@oralin
and got
ERROR:
ORA-12154: TNS:could not resolve service name
I did a search for ORA-12154 and found a windows-related doc with a solution.
The answer was to add the following to $ORACLE_HOME/network/admin/sqlnet.ora:
names.default_domain = x
where x is the same as the domain specified by the service_name.domain parameter in the tnsnames.ora file in the same directory.

Dedicated Server Process or Shared Server Process

Hi,
I am little confused to justify the number of users that may be best to use dedicated server process or shared server process.
Kindly advice.

In addition, make sure you account for administrative issues. It's a lot more challenging to trace applications using shared server connections. Shared server configurations also tend to introduce a variety of gotchas into a DBA's world-- at a minimum, most articles you find on the internet tend to ignore any shared server specific issues. That's one of the reasons that I tend to be of the opinion that if you have to ask, you probably don't need to enable shared server.
Justin

Shared server/dedicated server process doubt?

when oracle database is not configured for shared server is it compulsay to include SERVER=DEDICATED clause in the connect descriptor.?
Thankx.

Hi,
is it compulsay to include SERVER=DEDICATED clause in the connect descriptor.?No, the MTS is defined at startup time, via the MTS parms.
Here is a sample of shared server definition in the init.ora file:
# Multi-threaded Server parameters
local_listener="(address_list=
(address=(protocol=tcp)(host=sting.janet.com)(port=1521))
MTS_MAX_DISPATCHERS=5
MTS_MAX_SERVERS=20
MTS_DISPATCHERS="(ADDRESS=
(PROTOCOL=tcp)(HOST=sting.janet.com))(DISPATCHERS=3)
service_names=testb1
http://www.dba-oracle.com/unix_linux/epc_disabled.htm
However, be aware that the MTS is not a panacea, especially at times when you want to invoke a dedicated process for your program. For Pro*C programs and I/O-intensive SQL*Forms applications, or any batch processes that have little idle time, you may derive better performance using a dedicated listener process. For shops that segregate task into online and batch modes, the DBA sometimes create separate listeners—one with the MTS and another for dedicated connections.
Hope this helps. . . .
Donald K. Burleson
Oracle Press author

Shared server or dedicated servers

What's the defaul configuration? How i can check either i am running shared or dedicated server mode?
Which is common preference in different companies?

- The default is dedicated server.
- You can enable shared server connections as well, in which case you would (potentially) have both types of connections simultaneously. You cannot have a database that supports only shared server connections
- You can see if you have any shared server connections by selecting the SERVER column from V$SESSION
- In general, if you have to ask the question, use dedicated server. You would enable shared server only when you had a good reason to do so.
Justin

Dedicated Server Connection Vs Shared Server Connection

Hi Gurus,
I have few doubts regarding Dedicated Server Connection Vs Shared Server Connection -
1) How do I know which connection mechanism is configured in my system.
2) Which connection faster and reliable.
3) Is there any risk to using shared server connection?
4) Which concept is new comparatively?
5) It is possible to restrict specific user for Dedicated Server Connection and other for Shared Server Connection in a same database.
Regards,
Atanu

AChatterjee wrote:
Thanks for your post.... but still i have doubt on below points -
1) How do I know which connection mechanism is configured in my system.Search for dispatcher parameter (both words in the search box) in the docs.
2) It is possible to restrict specific user for Dedicated Server Connection and other for Shared Server Connection in a same database.You might be able to do something like this by using the RULE parameter with cman, limiting specific users (via local security setups) to specific client IP's and forcing them to particular service names. This is a net services issue, so does not conflict with what Billy said. It assumes you control whether your users will query the db appropriately, too. Many apps don't do that right.

Dedicated server or shared server ?

Hai ALl
What is the criteria for a Database set in dedicated server or shared server. This is users dependent or processes dependent?.How to change the mode(dedicated or shared) after database creation.
Please help...
Shiju

If you're not sure, use the default, which is dedicated server. You generally want to use shared server when you want to have more simultaneous sessions than your hardware could support without swapping and there aren't a lot of applications that really require this sort of thing. In the "olden days", one might also consider using shared server when the overhead of creating and destroying physical connections was a significant concern, but modern architectures (i.e. 3-tier development rather than client-server applications) generally makes that irrelevant because the middle tier can just use a connection pool.
Instructions on enabling shared server are in the documentation.
Note that just because shared server is enabled does not mean that all connections will use shared server. The client can always request a dedicated server connection.
Justin

Dedicated Server against Shared Server

I have a server on which we have installed several clients database isntances. Recently there were several performance issue for one of the client at which time I heard that was becasue of their instance is an shared server and if make it dedicated the performance will improve. How do you find out whether an instance running on a particular box is a dedicated server connection or shared server connection. What is the definition of those in simple lay mans terms. How do you change a shared connection to dedicated connection and vice versa? Does it depend on the memory/cpu size etc. Any help is higly appreciated.

Dear User,
Search on the forum.
http://forums.oracle.com/forums/search.jspa?threadID=&q=%22dedicated+shared+server%22&objID=f61&dateRange=all&userID=&numResults=15

How to convert a dedicated running oracle server to a shared server

i need help as to how to convert a dedicated running oracle server to a shared server.(step by step plz i am fairly a fresh person)
there are presently 10 users but have to configure for 125 users accessing from 5 locations.
also need how to implement connection manager

125 users are not so much, unless your database server is a quite small one. Anyway, you have to configure Dispatchers and Shared Servers. See Configuring Oracle Database for Shared Server
About Connection Manager see Configuring and Administering Oracle Connection Manager

Dedicated server/shared server

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