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Chapter 10: Putting It All Together: A Wholistic Approach
We have discussed many issues on tuning the Oracle8 database. In this chapter, we will Out it all together. To have a healthy Oracle environment, you need to tend to all the issues we have discussed, using a planned, methodical approach. We call the discussions here a wholistic approach. When tuning Oracle, you must look at the whole picture, not just the usual three-tiered approach of memory, 1/0, and important applications. Yes, the Big Three are the most important and they give the most noticeable results. Throughout this book, though, we have looked at many issues that require your attention during the tuning process; no stone can be left unturned.When your complete tuning exercise is done, you will have touched on most aspects of your database that require day-to-day attention. Think of your database as one of your loved ones:
- It craves your attention when you neglect it.
- It sends you messages when there is something wrong with it.
- It refuses to cooperate when you ask it to do too much.
- It confuses you when you tend to one problem when another actually needs fixing.
- It gets you up at all hours of the night.
- It tells you one thing when it means another.
- It sends you mixed messages.
- It thrives on TLC (tender loving care).
VLDB
The bigger the database, the more potential for bigger problems (just like teenage children compared to toddlers!).
But above all, you must provide it with the resources that enable it to succeed on its own! We believe that tuning Oracle is a process applied to all components of the software.Providing a stable, dependable operating environment is fundamental to a regimen that minimizes database downtime and data loss potential. This is a database administrator's most important priority. A down database is not a tuned database. We will discuss mechanisms you can put in place to care for and protect your database in the following areas:
- Backup The process whereby you make copies of your data from your database at fixed time intervals. Backup protects you against the assortment of hardware, software, and user-based errors that may occur.
- Recovery -The restoration of a backup of your database from a previous time period and rolling it forward using redo log files (roll forward is discussed in the "Tuning Database Recovery" section later in this chapter).
- Error routines DBA-defined mechanisms that you implement to alert you when predefined error situations happen with your database.
- Transaction control tuning features
- Efficient overall resource management
- Clusters and their potential performance gains
Let's get started by looking at the Oracle Connection Manager which, coupled with the multithreaded server on the Server side, allows connection pooling through the Net8 transport mechanism. The Oracle Connection Manager makes a contribution to the discussions in the journey we affectionately call Oracle8 Tuning.
Oracle Connection Manager
The Oracle Connection Manager is a feature of Net8 that allows you to set up a pool of network connections and have them shared among client connections as they require resources on the server. The heart of Oracle Connection Manager (OCM) is multiplexing, where more than one session becomes a single logical connection using the same network transport. Readers familiar with the multithreaded server (MTS) will hear a lot of jargon I and concepts similar to MTS when looking at using OCM, which intercepts requests for network services and routes them through a single channel.
WHOLISTIC RULE #1
Oracle Connection Manager communicates on the server end with a multithreaded server. If you are not running MTS on your host, connection pooling using OCM is not available.
Enabling Multiplexing
The multiplexing capability can be enabled by an OCM when a number of sessions are trying to communicate with the same multithreaded server and all the connection requests are initiated through the same OCM. The best analogy is to think of the requests as being at the top of a funnel, with the single physical connection at the bottom through which all the client requests pass. OCM maintains a logical connection to the server even when sessions are not requesting any services.
Additional Security Layer
You can introduce another layer of security using OCM since you can specify what hosts can be reached from what clients. Using OCM, you can specify a hostname or IP address of servers deemed to be reachable; an IP address is a four-part identification of servers and clients on a network. When you hear addresses such as "one three nine dot twelve dot one zero nine dot two," people are using these addresses.
WHOLISTIC RULE #2
If not already implemented, speak with your network personnel to implement a facility to use names rather than IP addresses for your servers. This especially makes sense when setting up Net8 configuration files. . . .