Re: Orace PARAMETERS

In article <6vca16$cr7$1_at_nnrp1.dejanews.com>,   dvsingh1_at_my-dejanews.com wrote:
> Hello,
>
> I wi be highly grateful to U if U can carify the below parameters.
> I need to create a new database :
>
> ------ Parameters in the creation script --------
> connect internal
> startup pfile=/orasw/v7/dbs/initcc10.ora nomount
>
> >> Why we do "nomount" here rather than MOUNT or OPEN, what is the difference
> between them.
>
> create database "CC1"
> maxinstances 1
> maxlogfiles 16
> character set "US7ASCII"
> datafile
> '/db01/oracle/CC1/sys01.dbf' size 20M reuse
> logfile
> '/db05/oracle/CC1/redo01CC1.dbf' size 2M reuse,
> '/db05/oracle/CC1/redo02CC1.dbf' size 2M reuse,
> '/db05/oracle/CC1/redo03CC1.dbf' size 2M reuse;
>
> >> What is the significance "maxlogfiles" here. can logfiles not go beyond the
> value specified ( 16 )??. What do we mean by log file groups ( is it 3 here).
>
> Suppose once the database is running nad the I shutdown it and add an
> additional entry for log file and restart the database ...will it work fine ?.
> The sys01.dbf is used for what purpose?. How does its size matter?.
>
> connect internal
> create rollback segment r0 tablespace system
> storage (initial 16k next 16k minextents 2 maxextents 20);
>
> >> Why we create this r0 rollback segment... what is the purpose of creating
it
> and then later making it offline.
>
> ------ Parameters in the configuration file --------
>
> what for are these parameters used:
>
> background_dump_dest = path -- for what types of dump it is used
> core_dump_dest = path -- for what types of dump it is used
> user_dump_dest = path -- for what types of dump it is used
>
> With Regards and Thanks in Advance........
> Dvsingh
>
> dvsingh_at_amsoftindia.com
>
> -----------== Posted via Deja News, The Discussion Network ==----------
> http://www.dejanews.com/ Search, Read, Discuss, or Start Your Own
>

Greetings, Dvsingh,

1. When a database is created, NOMOUNT indicates to start the instance (on UNIX, this means starting the database-related processes) without mounting the database, that is, making it available. This is logical, since there is no database at this point. Once the MOUNT command is issued for a database, it is in exclusive mode, and only available to the DBA (or a user with RESTRICTED SESSION privilege) to perform maintenance operations. Once the OPEN command is issued, the database is available for use by other users.
2. MAXLOGFILES indicates the maximum number of groups of online redo log files per database; this can range from 1 to the number specified in MAXLOGFILES Once this is specified, it cannot be changed without re-creating the database or the control file. Online redo logs are specified in groups, usually there are 1-2 log files per group.
3. When you run the CREATE DATABASE statement, it creates your SYSTEM tablespace (the file seen as 'SYS01.DBF'). This tablespace contains the SYSTEM rollback segment, the Data Dictionary and objects owned by the users SYS and SYSTEM. This tablespace is usually somewhere between 25 and 100M, depending on the amount of tables in and size of the database. The SYSTEM tablespace must always be online, and cannot be dropped (you would have no database at that point).
4. If your database will have more than one tablespace, you must have at least two rollback segments. When a database is created, in order to create other tablespaces, you must have a second rollback segment in the SYSTEM tablespace. Once this second rollback segment is created and is online, you can create other tablespaces. Usually, the first tablespace you would create after creating the second rollback segment in SYSTEM is a rollback segment tablespace:

           create tablespace RBSEG01
           datafile '/prod/rollback/rbseg01.dbf' size 300M
           default storage (
           initial      2M
           next         2M
           maxextents  249 [for a 4K database]);

You can optionally specify the OPTIMAL parameter; this specifies the size that the rollback segment shrinks back to after expanding.

4. BACKGROUND_DUMP_DEST specifies the location where the trace files for background processes and the ALERT file are written. The ALERT file (on UNIX, the file name is 'alert_database-name.log', so if your database was called test, the alert file would be: alert_test.log) is where Oracle writes events such as database startup/shutdown, tablespace creation/deletion, log changes and errors. It is important to check this file often; when there is a problem, it is one of the first places you should look.

USER_DUMP_DEST is where the trace files for server processes are written; many times if a user gets an ORA0600, indicating an internal error, the *.trc file would be written to this directory.

CORE_DUMP_DEST - some operating systems can write any core dumps to this directory. On UNIX, I've never seen an Oracle core dump written here, but that's just my experience.

Some references for you to consult (as part of your Oracle software, you should have gotten a CD entitled 'Oracle Product Documentation Library'):

            Oracle7 Server Administrator's Guide
            (Chapter 2 - Creating a Database, Chapter 3 - Starting and
             Stopping a Database)

            Oracle7 Server Reference

Both of these are on the CD I mentioned above. You should also check out some of the Oracle Press books like 'Introduction to Oracle'.

I hope this helps. To summarize, the steps in creating an Oracle database are:

1. Preparation - the Installation Guide usually will tell you all the things you have to do to your operating system, and what init.ora parameters you need to set.
2. Installing the Oracle software
3. Creating the database (Server Mananger, Line Mode, UNIX):
4. At the system prompt:

     svrmgrl
     connect internal
     startup nomount

B. Run the CREATE DATABASE script

C. Create a second rollback segment in the SYSTEM tablespace and alter it ONLINE D. Create the Data Dictionary, etc:

   @$ORACLE_HOME/rdbms/admin/catalog.sql     (creates Data Dictionary)
   @$ORACLE_HOME/rdbms/admin/catproc.sql     (enables the Procedural Option)
   @$ORACLE_HOME/rdbms/admin/catexp.sql      (allows you to do Export/Import)

E. Create your rollback segment tablespace, your TOOLS, USERS and TEMP tablespaces, and the tablespaces for your application tables and indexes

F. Change the ROLLBACK_SEGMENTS= parameter in the init.ora to have the name of the rollback segments you created

G. Change the passwords for the SYS and SYSTEM users and the DEFAULT and TEMPORARY tablespaces.

H. Connect as SYSTEM and run

   @$ORACLE_HOME/rdbms/admin/catdbsyn.sql (Data Dictionary synonyms)

   @$ORACLE_HOME/sqlplus/admin/pupbld.sql       (Creates USER_PROFILE and
                                                 PRODUCT_USER_PROFILE tables
                                                 for SQL*Plus)

I. Shutdown your database and start it up again:

    shutdown
    startup

At this point, if you do a

'select segment_name, tablespace_name, status from dba_rollback_segs', you should see that the ones you created in your rollback segment tablespace are ONLINE, and the second one you created in the SYSTEM tablespace should be OFFLINE. You can drop this second rollback segment, or leave it for future maintenance.

Dvsingh, I hope this helps. If you have other questions, or need help, I would be glad to assist you:

           Ms. Yaca Attwood
           yaca_attwood_at_averydennison.com






-----------== Posted via Deja News, The Discussion Network ==----------
http://www.dejanews.com/       Search, Read, Discuss, or Start Your Own