Understanding Ingres Components

This chapter discusses the Ingres components, utilities, and tools available to the system administrator to work with Ingres.

Responsibilities of a System Administrator

The system administrator has all privileges and holds the primary responsibility for installing and maintaining Ingres. The system administrator (often referred to as the installation owner) owns the user ID specified during Ingres installation. Logging in as this user provides permissions that are needed for installation and maintenance.

The system administrator has the following responsibilities:

• Installing Ingres (and optional components)
• Authorizing users to access Ingres
• Defining Ingres variables such as II_DATABASE and II_INSTALLATION
• Starting, stopping, configuring, and monitoring servers
• Disconnecting or suspending a session connected to a server
• Shutting down the Ingres installation (or its components)

Components of an Ingres Installation

The system administrator installs and maintains the following principal components or associated family of compatible components:

• DBMS Server
• Internet Communication
• General Communication Facility
• Querying and reporting tools
• Visual tools, if available in your environment
• Logging and locking systems

An Ingres installation also has:

• Library files and utilities, provided with the product distribution
• Configuration files and error log files, created during installation and at runtime by Ingres
• Databases and their associated files: the checkpoint, journal, dump, and work files, also created by Ingres during installation and at runtime

The locations of these files are selected at installation time, together with the configuration of the Ingres DBMS Servers and the logging and locking systems. For the initial installation, default settings are provided by the system whenever possible.

After the installation is running, all Ingres servers must be monitored to ensure that they are running and that they are configured for top performance. You can also configure selected Ingres parameters.

DBMS Server

The Ingres client-server architecture allows multiple users access to databases through connections to one or more DBMS Server processes. The DBMS Server (iidbms) is a multi-threaded daemon process that performs asynchronous disk input and output. The number of users connected to a server is limited by hardware or the operating system.

Since it is unlikely that the default DBMS server configuration suits all users' requirements, the DBMS Server is usually configured to improve performance in a particular configuration. For a selected DBMS server definition, its buffer caches can be configured as well as other parameters and derived parameters.

DBMS servers can be configured to fit specific needs. For example, you can:

• Designate one server to access a particular database, denying other servers access to that database.
• Configure a server as a "fast commit" server to achieve higher levels of performance.
• Specify that two or more servers share a common memory buffer cache.
• Specify private buffer cache with distributed multi-cache protocol.

Some elements of the DBMS Server are described as facilities.

Note: Ingres preallocates most of the resources it requires. It may use hundreds of megabytes of virtual memory and allocate hundreds of thousands of handles; the use of these resources depends on the number and size of the page caches enabled.