Re: Oracle questions

Hi,

    I have interspersed my comments after your questions.

a_andy_at_my-dejanews.com wrote in message <6uauts$f7q$1_at_nnrp1.dejanews.com>...
>Hi! Everybody,
>
>I am a new DBA. I have a few questions related to Oracle. Please provide
>complete description wherever you can.
>
>1. How to install different databases on the same unix/NT server ? How
would
>t be defined for individual unix users ? How would I
startup/shutdown/backup

        Use svrmgr to do this. With your database shutdown do a connect and then run a database creation script (see the Oracle Press DBA Handbook by Kevin Loney for a sample script.)

        The databases are differentiated by the sids. For example on one of my systems I have a 7.3.3 sid called edgd and an 8.0.4 sid called lms1

        Edit /etc/oratabs and set the last argument on each line to Y and if your system is already set up to start up Oracle at boot time .... Now as to shutting down, oops sorry I don't remember -- after all who ever shuts down an Oracle database?

>2. Can same server have multiple versions of database ? How to install them
?
>What are the steps/ precautions to be taken ?

    Yes. See above info on using svrmgr.

    No special precautions are required.

>3. What are the different steps for sizing of database,table,tablespace,
>indexes ?

    In the latest versions of Oracle the most important factor in sizing in terms of both performance and efficient space management is to size everything in multiples of your number of db block buffers times the db block buffer size (I bet I get a lot of flames here).

    The amount of planning you do in regards to sizing should be directly proportional to the stability of your RDBMS environment. In my own case we start up an average of three new database applications per week and kill off just as many. Given the unstable environment I perfer to use rules of thumb. One of my favorite rules is to double the data space in order to allow for indexes and system overhead. It must work since I haven't run out of space yet.

>
>4. Where to use clusters ?
>

    Clusters are great where you have two or more tables that are accessed in parallel. For example in a lead tracking application with one table for leads and one table for sales the use of a cluster will minimize disk activity providing that all (most) of the tables in the cluster are accessed for data pertaining to an individual when any of the tables are accessed to get or update information about theat individual.

>5. What is the significance of different storage parameters ?

    Read the fine manual.

>
>6. What is the difference b/w sys and system user ?
>

    Except for those tasks which Oracle specifically requires be done by either SYS or SYSTEM neither account should be used. SYS has even greater privileges than SYSTEM and its improper use can screw up your database even faster than the improper use of SYSTEM.

>7. What is the difference b/w parallel query and parallel server ?

    Think of Parallel Query as being a multithreaded application where a single server can launch multiple tasks each of which is a query to a partition or segment of a database.

    Parallel Server means that there are more than one servers involved in executing the query. The work is distributed among the serves in ways known only in Redwood City CA.

>
>8. Could you suggest some site to learn about SQLNET, Backup/recovery,
sizing
>?

    Follow the comp.databases.oracle newsgroups.

regards

Jerry Received on Thu Sep 24 1998 - 12:24:33 CDT