Multiple Databases One Instance

Hello,
Is it possible to have multiple MaxDB databases installed within one MaxDB instance? Everything I've read about MCOD leads me to avoid this if possible; however, budget limitations leave our hardware lacking the ability to host multiple DB instances.
It will be a NetWeaver WebAS ABAP and a NetWeaver WebAS J2EE instance being installed (ECC and EP). I've worked with MCOD systems before, and system copies were cumbersome. More or less I did a DB specific migration for the ABAP, and then did a R3Load for the J2EE. If that is the only option, then that is the only option. I would just like to be able to document this ahead of time.
Thank you,
Zach

Mark,
Thank you for the reply. I'm going through this presentation; however, it looks very familiar. MCOD does allow
for different SAP components to be independently installed into 1 MaxDB instance, but is it possible to do system
refreshes of these servers easily? If I remember correctly, I was able to use the SAP provided tools for the first
component. But every other component had to be done independently using R3Load because the SAP Tool
using database specific copies required initialization (formatting) of the database.
I've been reading a current post in this forum regarding features of MaxDB 7.8. I suppose the question is now:
what is the lesser evil? MCOD (NetWeaver WebAS ABAP & NetWeaver WebAS J2EE) or each component in
its own MaxDB instance on the same host.
Thanks,
Zach

Similar Messages

Need help to create a login for maintenance of a single database in a multiple databases, single instance environment

Hi,
We are in the process of consolidating several databases on a single instance of SQL Server 2012.
Databases are developed by outside vendors; they have to be able to install and support their databases but they shouldn't be able to do any thing with the other databases.
When I tried to migrate the first database, the vendor told me that on the former server he used the sa account in some batch.
On a previous thread
https://social.technet.microsoft.com/Forums/sqlserver/en-US/dc1f802f-d8de-4e2b-87e5-ccb289593fb7/security-for-multiple-applications-on-a-single-sql-server-2012-instance?forum=sqlsecurity
it was suggested to me that I create a login for each vendor and that this login should map a user in their respective databases.
To test, I simulated the process in a test database:
1 - I create the login and I scripted the command:
USE [master]
GO
/* For security reasons the login is created disabled and with a random password. */
/****** Object: Login [M02_Test] Script Date: 2014-12-02 16:23:58 ******/
CREATE LOGIN [M02_Test] WITH PASSWORD=N'ÈS^y¡¶=Å€"+y¤j|úªhÖféÎÐ•œEu
c', DEFAULT_DATABASE=[M02], DEFAULT_LANGUAGE=[us_english], CHECK_EXPIRATION=OFF, CHECK_POLICY=OFF
GO
ALTER LOGIN [M02_Test] DISABLE
GO
2 - I create the user and scripted it
USE [M02]
GO
/****** Object: User [M02_Test] Script Date: 2014-12-02 16:29:41 ******/
CREATE USER [M02_Test] FOR LOGIN [M02_Test] WITH DEFAULT_SCHEMA=[dbo]
GO
Questions:
What should we do with te scrambled password: is it saved as it was entered and should it be kept somewhere in a safe place?
Would that do the job for the vendor who used sa before?
Thanks for your advice

I'm not sure why you would save the script. Why not create the login, in one way or another give the vendor the password. Keep the login disabled until needed.
I don't recall exactly what we said last time, but it occurs to me that the application setup things on server level. Jobs is the prime thing that comes to mind, but there could be other things.
Now, here is an important observation. As long as the vendor's application was alone on the server, that was OK, and it was OK to give the vendor sysadmin rights. In this situation this is less OK, and as we said, you should only give the vendor db_owner
in the database.
But the vendor will need to tell you what they do on server-level. They should know this - unless they sell their app as a "alone-on-a-server application". (And there are indeed such applications out there, even from Microsoft.) But there is a
risk that they will bill you extra if you make their installation more difficult.
Maybe you will have to give some vendors sysadmin for the installation, but in such case, you should ask them why they need it. If they don't, give them db_owner, and they will have to find out their hard way. (And you don't pay them for learning
their own application.)
Erland Sommarskog, SQL Server MVP, [email protected]

How to investigate high io in a RAC with multiple databases?

how to investigate high io in a RAC with multiple databases?

RAC is saying that a single server lacks the processing capacity needed for databaseA. So additional databaseA instances on additional servers are needed in order to meet the processing demands for databaseA. Thus RAC is required.
Multiple databases on a single server says that the server has spare processing capacity and that it can not only deal with databaseA processing demands, but also with the processing load of databaseB.
So how does your statement about running multiple database RAC instances on the same RAC server node, make sense? And does your I/O issue not immediately point to the fact that no, RAC server1 cannot deal with the I/O resources required by both databaseA and databaseB?
After all, how is I/O scaled on RAC? How is ANYTHING scaled on RAC? By adding more databases to a RAC server node? Of course NOT!!
RAC scales by adding more servers (with a new database instance each) to a physical database in order to scale processing capacity and I/O. By adding more I/O channels to access the SAN/shared storage. By adding more CPUs to increase processing capacity.
Bluntly put - multiple RAC database instances on a single RAC server node is kind of an idiotic approach to scalability in my view....

Can we link one application instance with multiple databases ?

We have R12.1.1 and db is 11.1.0.7 on redhat 5.3 ( 64 bit).
Can we link one application instance ( apps / , inst / ) with multiple database ( db / ),
is this possible ?
if yes how ?

>
Can we link one application instance ( apps / , inst / ) with multiple database ( db / ),
is this possible ?
No. You cant link application tier with more than one database.
Similar query already answered by Hussein in detail in the forum :Re: Multiple instances, single Apps tier Please check that for more details
-Rk

Multiple Logical Systems in Partner Profile for one instance

Can we create multiple Logical Systems in Partner Profile (WE20) for one instance or one System? If it is possible, can we create Logical System with respect to Plant/Country?

I am not quite sure if I understood your problem completley. But let's see...
Usually you use on on MSCS Cluster Group per SAP instance. So you have your already existing NW 7.0 ABAP stack in a separated Cluster Group, and you create a new Cluster Group for your new Java system.
You can find more information about it in this guide here on SDN:
Link: [High Availability;
More information about High Availability Setups for SAP System can be found here on SDN:
Link: [High Availability]
If you want to use the same database for your clustered ABAP stack and your new Java stack you can do a MCOD installation.
Please see Link: [SAP Note 388866 - Multiple Components on One Database - Installation|https://service.sap.com/sap/support/notes/388866]
Hope this helps.
Best regards,
Mathias

Can i create more than one instance for single database?

HI
anybody can tell me how to create more than one instance for single database(without using RAC)?
thanks
Kalanidhi

Anandji,
I sometimes think differently. I also think like what this person is asking..(although I have installed and administering 5 different RAC databases)
The main doubt of mine is that we create multiple instances accessing the same storage area.
Anyway the controlfiles of all instances will have the same information except the instance_names and instance id's.
Hence I always think , why can't it be possible to to create another instance in the same system and point it to a controlfile which is copied from the other instance.
Why can't the same files be shared between the two instances in a same system ?
I know I am thinking a little bit confusing...
Anyway I need to test that also...
Mahesh.

How to access multiple database present in single instance

Hi Team,
In oracle 11.2, can there be multiple databases in an instance??? In one of our environment, I could see multiple databases in an instance. Could you please help me in giving the data dictionary or query to access those databases?
Actually, querying v$database, I could see only one database which is same as instance name. But in inventory, there are multiple database in an instance?
I am still not exactly clear about this. Can someone help me with this?
Thanks!
Vidhya

In Oracle one instance manages one (1) database. A database consists of multiple *schemas*.
Other vendors erroneously call a schema 'database'.
So, no, you didn't see multiple databases.
There is also one datadictionary, consisting of a set of views.
All views beginning with dba_ list the entire database, all schemas.
All views beginning with all_ list the objects you have access to.
All views beginning with user_ list your own objects.
The view DICT show you the contents of the datadictionary.
Oracle also has online documentation at http://docs.oracle.com
From your question it is clear you should read the document called the 'Oracle Concepts Manual'.
You can find all documentation for 11gR2 here Oracle Database Online Documentation 11g Release 2 (11.2)
Too many people here don't make any effort to read it. This is probably the reason why you got no response.
Sybrand Bakker
Senior Oracle DBA

Can one instance have multiple redo threads ?

i was reading the Oracle Data guard 10g guide and it says
Determine the appropriate number of standby redo log file groups.
Minimally, the configuration should have one more standby redo log file group than the number of online redo log file groups on the primary database. However, the recommended number of standby redo log file groups is dependent on the number of threads on the primary database. Use the following equation to determine an appropriate number of standby redo log file groups:
(maximum number of logfiles for each thread + 1) * maximum number of threads
Using this equation reduces the likelihood that the primary instance's log writer (LGWR) process will be blocked because a standby redo log file cannot be allocated on the standby database. For example, if the primary database has 2 log files for each thread and 2 threads, then 6 standby redo log file groups are needed on the standby database
while Oracle's definition of redo log states the following
Redo Threads
When speaking in the context of multiple database instances, the redo log for each database instance is also referred to as a redo thread. In typical configurations, only one database instance accesses an Oracle Database, so only one thread is present. In an Oracle Real Application Clusters environment, however, two or more instances concurrently access a single database and each instance has its own thread of redo.
this is confusing, in a typical environment where only one instance accesses a database, can we have more than one redo thread ?

Though you can create multiple threads but of no use in NON-RAC or non-parallel server configuration.
Following is the generic formula. You should consider
maximum number of threads = 1 for single instance (NON-RAC).
(maximum number of logfiles for each thread + 1) * maximum number of threads
Message was edited by:
Reega

Need to get data from multiple database instances in a single query

Hi,
I need a small favour from you guys. The prob is as follows:
I need to get name, row_id from table A from schema 1 and gbu_name, name from table B from schema 2 where a.name = b.name. I wrote the query in the following manner:
SELECT a.name, a.row_id, b.gbu_name
FROM Schema1.A as a, Schema2.B as b
Where a.name = b.name
But this query is not working and the error is like " The table does not exists".
Please update me how to avoid the error and get the right sort of result.
Thanks & Regards,
Debabrata

Ah, youre actually asking different things.
In your topic title, you say youre running separate instances
In your body text, you say you are under different user/schema
So tell me, do you have more than one database or not? How many entries in your TNS file?
I would say, for "multiple database instances"
SELECT
a.id, b.id
FROM
tableA a
INNER JOIN
tableB@OTHER_DATABASE_LINK_NAME b <--NOTE!
USING(id)And of course you will have to look up CREATE PUBLIC DATABASE LINK sql..
Message was edited by:
charred

Multiple Database Instances on Single Server and effect of NLS_LANG

What is the effect of the NLS_LANG registry setting on a Windows server that is to host multiple database instance each created with a different database character set ? The server needs to support data in the following languages : Thai, Chinese Traditional, Chinese Simplified, Vietnamese and Korean. Selecting the Unicode character set(AL32UTF8) is not an option since the application is not Unicode complaint.
My understanding is that as long as NLS_LANG is set correctly on the client connecting to the particular database instance then the data will be stored correctly - is this correct ?
What should NLS_LANG be set to on the server if there are multiple oracle instances with different character sets ?

My question is not in relation to connecting to the database on the server itself but with regards to client connections. What I need to know is what is the effect of the NLS_LANG setting in the registry on a server that has multiple databases each created with a different character set ?
Say for instance, the server has two databases - one created with the character set ZHS16GBK and the other created with the character set JA16SJIS and NLS_LANG is set to SIMPLIFIED CHINESE_CHINA.ZHS16GBK in the registry on the server. Will Japanese data that is inserted into the database that has character set JA16SJIS be stored correctly when it is inserted from a client with NLS_LANG set to JAPANESE_JAPAN.JA16SJIS even though NLS_LANG is set to SIMPLIFIED CHINESE_CHINA.ZHS16GBK on the server ?

Multiple databases in one single RAC cluster

Hi, I would like to know if one can have multiple databases running on a single RAC cluster, we have several databases in our shop and would like to consolidate all of them into a single 3-4 node RAC cluster running databases with 10.2 and 11.1 versions.
I am newbie to RAC and would like to get some clarification if anyone has done this, google search comes up with few hits on this topic, so obviously this is not doable.
In our case we have one database supporting critical applications and few other not so critical but are used very extensively between 9-5, so what is the use of RAC if I cannot consolidate all my databases into one cluster, or if I need a separate cluster for each of these critical databases?
I have been all the Oracle docs that keep repeating one database multiple instances and one instance-one machine-one node, they don't even advise running multiple instances on a single node?.
I appreciate any insight.
Thanks.

ora-sql-dba wrote:
Can you give more details on how you would setup multiple databases running different versions on a single RAC cluster, I am yet to find any documentation that supports or even elaborates on this topic.You can configure a cluster with 12 nodes. Then, using dbca, configure a dev instance for nodes 1 and 2, a prod1 instance for nodes 3 to 6 and a prod2 instance for nodes 7 to 12.
You also can configure each of these instances for all 12 nodes. And use it on all 12 nodes.
Or, after configuring it for all 12 nodes, you can start the dev instance on nodes 1 and 2, prod1 on 3 - 6 and prod2 on the remaining nodes. If dev needs more power, you can for example shutdown prod2 on node 12 and start another dev instance there.
My issue is with the 2nd option - running more than one instance on the same node or server. Why? Each instance has a basic resource footprint ito shared memory needed, system processes required (like db writer, log writer, sys monitor) etc. It does not make sense to pay for that same footprint more than once on a server. Each time you do, you need to reduce the amount of resources that can be used by each instance.
So instead of using (for example) 60% of that server's memory as the SGA for a single instance, if you use 2 instances on that server you now have to reduce the SGA of each to 30% of system memory. Effectively crippling those instances by 50% - they will now have smaller buffer caches, require more physical I/O and be more limited in what they can do.
So unless you have very sound technical reasons for running more than one instance on a server (RAC or non-RAC), do not.

Ref: Multiple databases on same ASM Instance

I am having an existing two Node RAC using ASM FIle System. I want to add one more database to the existing RAC using the same ASM diskgroup. We can create multiple databases using the same ASM instance?

You need one ASM instance per server. You can have multiple instances resp databases running on that server accessing the same diskgroup made available on the server by the ASM instance.
Kind regards
Uwe Hesse
http://uhesse.wordpress.com

Multiple databases in one file: a small snafu

Hello everyone,
Opening multiple databases in a single file is an administrative convenience. It is well explained in the manual (see db/docs/ref/am/opensub.html). Normally, there is little difference between databases in their own physical files or grouped together in a single physical file. There is one small sentence in the manual that says the following:
(begin fragment)
However, since multiple databases in a file exist in a single physical file, opening two databases in the same file simultaneously requires locking be enabled unless all of the handles are read-only. As the locks for the two databases can only conflict during page allocation, this additional locking is unlikely to affect performance.
(end fragment).
I didn't pay attention to it, except the "unlikely to affect performance" part which told me that I wasn't to worry about it. The sun was shining. Life was good.
And I was wrong. It was one of those "epic bug quests" I had to embark on, only to realise that it may not be a BDB bug, but my carelessnes. Nevertheless, I'm left with an uneasy feeling which I would like to explain here.
Consider BDB configured as a concurrent data store.
There are 2 threads. The first thread has the following pseudocode:
cursor1 = db1->cursor(...)
while(cursor1->c_get(... DB_NEXT...))
// 1
cursor2 = db2->cursor(...)
while(cursor2->c_get(... DB_NEXT...))
The second thread does only the following:
db3->put(...)
db1, db2 and db3 are all distinct databases. All cursors are read-only (the cursor implicitly used in db3->put is of course a write cursor).
While the first thread is running, the second thread executes db3->put(...) at "//1".
Question: what happens?
Answer 1: if db1, db2 and db3 reside in different physical files, nothing special happens. Everything proceeds as it should.
Answer 2: if db1, db2 and db3 reside in the same physical file, both threads block "sometimes".
The "sometimes" used here means "when the put operation in thread 2 needs to allocate a new page".
Reading the BDB source code is extraordinarily difficult (which says more about my limitations than about the clarity of the code) but here is what happens, as far as I could determine:
(thread 1) cursor1 needs and acquires a read lock on db1
(thread 2) db3->put needs a write lock on db2 to allocate a new page. Since db2 is in the same physical file as db1 and thread 1 already has a read lock, thread 2 waits until the read lock is released. Thread 2 blocks.
(thread 1) cursor 2 needs a read lock on db3. For some reason, BDB detects that the another thread is waiting for a write lock on the physical file, and thread 1 blocks.
Both threads block waiting on each other to complete.
I suppose the system is the way it is to avoid starvation, but there you have it: be careful when you're lumping together multiple databases in one file!
Anyone who can clarify or confirm this is welcome.
Vincent

I had experienced a similar problem. I run multiple process. Each one of them starts a transaction that does db->put and db->pget to its own database (which also has a secondary index). When each database is in a separate physical file there is no problem but when I put all databases in a single file the processes start to dead-lock.
The following combination of options solved the deadlocking problem:
- use serializable isolation level instead of snapshot, i.e. do not pass DB_TXN_SNAPSHOT to txn_begin
- do not pass the DB_NO_WAIT option to txn_begin
- use Btree instead of a Hash
Hope that helps.

How to move worksheet saved on database from one instance to another?

Hi Every one,
How to move worksheet or workbook saved on database from Discoverer plus from one instance to other instance?
Is there any way to save a workbook or work sheet on to local drive from discoverer plus.?
Thanks
santhosh

Hi,
You have 2 options: use Discoverer Administrator to export/import the workbook; or use Discoverer Desktop to save the workbook to the local drive.
You cannot save a workbook to the local drive using Discoverer Plus.
Rod West

One instance and two databases?

Hello, I've installed oracle database on my server. I've read a lot of documentation to learn the basic concepts.
Ok, I have a question. I have read that one instance only can manage ONE database. Is it true? If it's true, how on earth I can create two database? for example, I want to create database-one and database-two.
I would create these with CREATE DATABASE command. How does Instance know if I want to access to database-one or database-two. How I indicate it in initilitation parameter file of my instance?
In sumary, Can one instance works with two databases?

Look at the following output. If I do not set my ORACLE_SID variable, the 9.2.0.7 client connects to the 9.2.0.7 database instance. If I set my ORACLE_SID , the same 9.2.0.7 client now connects to the 10.2.0.1 database (the database specified in the ORACLE_SID variable).
C:\>set ORACLE_SID=
C:\>sqlplus kkishore/kkishore
SQL*Plus: Release 9.2.0.7.0 - Production on Mon Jul 17 09:27:55 2006
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle9i Enterprise Edition Release 9.2.0.7.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.7.0 - Production
SQL> exit
Disconnected from Oracle9i Enterprise Edition Release 9.2.0.7.0 - Production
With the Partitioning, OLAP and Oracle Data Mining options
JServer Release 9.2.0.7.0 - Production
C:\>set ORACLE_SID=ORA10GR2
C:\>sqlplus kkishore/kkishore
SQL*Plus: Release 9.2.0.7.0 - Production on Mon Jul 17 09:29:31 2006
Copyright (c) 1982, 2002, Oracle Corporation. All rights reserved.
Connected to:
Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL> disconnect
Disconnected from Oracle Database 10g Enterprise Edition Release 10.2.0.1.0 - Production
With the Partitioning, OLAP and Data Mining options
SQL>Message was edited by:
Kamal Kishore

Multiple Databases One Instance

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