Informix Administrator Guide

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INFORMIX-SEDatabase Server

Administrators Guide

Version 7.2April 1996Part No. 000-7895A


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ii INFORMIX-SE Administrators Guide

Published by INFORMIX Press Informix Software, Inc.4100 Bohan non Drive

Menlo Pa rk, CA 94025

The following are worldwide trademarks of Informix Software, Inc., or its subsidiaries, registered in theUnited States of America as indicated by , and in n umerou s other countries worldwide:

INFORMIX; C-ISAM; INFORMIX-OnLine Dynamic Server

The following are worldw ide trad emarks of the ind icated ow ners or their su bsidiaries, registered in theUnited States of America as indicated by , and in n um erous other countries worldwide:

Adobe Systems Incorporated: PostScript

Nov ell, Inc.: NetWare

X/ OpenComp any Ltd.: UNIX; X/ Open

Some of the prod ucts or services mentioned in this docum ent are provided by companies other than Informix.These products or services are identified by the tra demar k or servicemark of the app ropriate company. If youhave a question about one of those products or services, please call the company in question directly.

Docum entation Team: Brian Deutscher, Geeta Karmarker, Mary Kraemer, Patrice ONeill, Eileen Wollam

Copyr ight 1981-1996 by Informix Software, Inc. All righ ts reserved .

No p art of this work covered by the copyright hereon may be reprodu ced or used in any form or by any

meansgrap hic, electronic, or mechan ical, including p hotocopying , recording , taping, or informa tion storageand retrieval systemswithout perm ission of the p ublisher.

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Software and accompa nying materials acquired w ith United States Federal Government funds or intended foruse w ithin or for any United States federal agency are p rovided w ith Restricted Rights as d efined in DFARS252.227-7013(c)(1)(ii) or FAR 52.227-19.


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Table of Contents

Table ofContents

Introduction

About This Manual . . . . . . . . . . . . . . . . . . 3Organization of This Manual . . . . . . . . . . . . . 3

Types of Users . . . . . . . . . . . . . . . . . . 4

Software Dependencies . . . . . . . . . . . . . . . 4

Demonstration Database . . . . . . . . . . . . . . 5

New Features of This Product . . . . . . . . . . . . . . 8Conventions . . . . . . . . . . . . . . . . . . . . 8

Typographical Conventions . . . . . . . . . . . . . 9

Icon Conventions . . . . . . . . . . . . . . . . . 10

Command-Line Conventions . . . . . . . . . . . . . 11

Sample-Code Conventions . . . . . . . . . . . . . . 14

Additional Documentation . . . . . . . . . . . . . . . 14Printed Documentation . . . . . . . . . . . . . . . 15

On-Line Documentation . . . . . . . . . . . . . . 16Related Reading . . . . . . . . . . . . . . . . . 17

Compliance with Industry Standards . . . . . . . . . . . 18

Informix Welcomes Your Comments . . . . . . . . . . . . t19

Chapter 1 Instal la tion and Ini tial Conf iguration

Defining a Database Management System . . . . . . . . . . 1-3

Planning for SE . . . . . . . . . . . . . . . . . . . 1-4

Configuring Hardware . . . . . . . . . . . . . . . 1-4Placing Active Tables and Files on the Disk . . . . . . . . 1-4

Considering SE Limits . . . . . . . . . . . . . . . 1-5

Installing SE . . . . . . . . . . . . . . . . . . . . 1-6

Preparing SE Connections . . . . . . . . . . . . . . . 1-6Understanding Version 7.2 SE Configurations . . . . . . . 1-7

Setting Environment Variables . . . . . . . . . . . . 1-8

Understanding the Communication Files . . . . . . . . . 1-9

Build ing the sqlhosts File . . . . . . . . . . . . . . 1-12Examples of Client/ Server Connections . . . . . . . . . 1-18


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iv INFORMIX-SE Administrators Guide

Connecting with Different Versions . . . . . . . . . . 1-26

Starting the sqlexecd Daemon . . . . . . . . . . . . 1-35

Using an NFS-Mounted Directory . . . . . . . . . . . 1-37

How Does a Clien t Application Connect to a Database Server? . . 1-38

Chapter 2 INFORMIX-SE System Architecture

SE Program Files . . . . . . . . . . . . . . . . . . 2-3

SE System Files . . . . . . . . . . . . . . . . . . . 2-4

The .dat File . . . . . . . . . . . . . . . . . . 2-5The .idx File . . . . . . . . . . . . . . . . . . 2-6

Allocating Space for .dat and .idx Files . . . . . . . . . 2-6

Transaction-Log Files . . . . . . . . . . . . . . . . . 2-6Allocating Space for the Transaction-Log File . . . . . . . 2-8

Audit-Trail Files . . . . . . . . . . . . . . . . . . 2-8

Permissions of Database Files and Directories . . . . . . . . 2-10

Determining If a Database Is ANSI Compliant . . . . . . . . 2-12

Chapter 3 Basic Administ ra tion and Maintenance

Monitoring Disk-Space Use . . . . . . . . . . . . . . 3-3

Maintaining Data Integrity . . . . . . . . . . . . . . . 3-4Transaction-Log Files . . . . . . . . . . . . . . . 3-4

Audit-Trail Files . . . . . . . . . . . . . . . . . 3-6

Creating Backups . . . . . . . . . . . . . . . . . . 3-6

Chapter 4 INFORM IX-SE IndexingB+ Tree Organization . . . . . . . . . . . . . . . . . 4-3

Searching for a Row . . . . . . . . . . . . . . . . 4-5

Adding Keys . . . . . . . . . . . . . . . . . . 4-6

Removing Keys . . . . . . . . . . . . . . . . . 4-11

Index-Table Structure . . . . . . . . . . . . . . . . . 4-12Multiple Indexes . . . . . . . . . . . . . . . . . 4-13

Index-Table Formats . . . . . . . . . . . . . . . . . 4-15

Chapt er 5 Symptoms and Solutions

Permission Problems . . . . . . . . . . . . . . . . . 5-3

Corruption Problems . . . . . . . . . . . . . . . . . 5-4Operating-System Failures . . . . . . . . . . . . . 5-4

Premature Termination of an sqlexec Process . . . . . . . 5-5

Physical Disk Corruption . . . . . . . . . . . . . . 5-5

Lost and Damaged Index and Data Files . . . . . . . . . 5-6

Transaction-Log Corruption . . . . . . . . . . . . . 5-7


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Table of Contents v

Disk Fragmentation . . . . . . . . . . . . . . . . . . 5-8

Practices to Avoid . . . . . . . . . . . . . . . . . . 5-8

Performance Tuning . . . . . . . . . . . . . . . . . 5-9

Chapter 6 INFORM IX-SE Utilities

The secheck Utility . . . . . . . . . . . . . . . . . . 6-3Choosing Not to Specify the -n or -y Option . . . . . . . . 6-5

Simple Example . . . . . . . . . . . . . . . . . 6-6

Output . . . . . . . . . . . . . . . . . . . . . 6-6Parenthetical Values . . . . . . . . . . . . . . . . 6-7

Printing a Long List of Index Key Values . . . . . . . . . 6-8

An Example Using the -l Option . . . . . . . . . . . . 6-10

Converting Index-Node Size with the -s Option . . . . . . 6-11

Causes for secheck Failure . . . . . . . . . . . . . . 6-11

The selog Utility . . . . . . . . . . . . . . . . . . . 6-12Displaying the Contents of a Transaction Log . . . . . . . 6-12

Use and Output . . . . . . . . . . . . . . . . . . 6-20

Index


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Introduction

About This Manual . . . . . . . . . . . . . . . . . . . 3Organization of This Manual . . . . . . . . . . . . . . 3

Types of Users . . . . . . . . . . . . . . . . . . . 4

Software Dependencies . . . . . . . . . . . . . . . . 4

Demonstration Database . . . . . . . . . . . . . . . 5

New Features of This Product . . . . . . . . . . . . . . . 8Conventions . . . . . . . . . . . . . . . . . . . . . 8

Typographical Conventions . . . . . . . . . . . . . . 9

Icon Conventions . . . . . . . . . . . . . . . . . . 10

Comment Icons . . . . . . . . . . . . . . . . . 10Compliance Icons . . . . . . . . . . . . . . . . 10

Command-Line Conventions . . . . . . . . . . . . . . 11

Sample-Code Conventions . . . . . . . . . . . . . . . 14

Additional Documentation . . . . . . . . . . . . . . . . 14Printed Documentation . . . . . . . . . . . . . . . . 15

On-Line Documentation. . . . . . . . . . . . . . . . 16

Error Message Files . . . . . . . . . . . . . . . . 16Release N otes, Docum entation N otes, Machine N otes . . . . 17

Related Reading . . . . . . . . . . . . . . . . . . 17

Compliance with Industry Standards . . . . . . . . . . . . 18

Informix Welcomes Your Comments . . . . . . . . . . . . . 19

Introduction


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2 INFORMIX-SE Administrators Guide


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Introduction 3

This chap ter introd uces theINFORMIX-SE A dministrators Guide. Readthis chapter for an overview of the information provided in this manu al and

for an u nderstanding of the conventions used throughout this manu al.

The INFORMIX-SE database server is ideally suited for small- to med ium-

sized database app lications. Informix based the SE database server on the

indexed sequ ential access method (ISAM), a library ofC language calls that

work with UNIX to manipulate database files. ISAM uses an index to access

data instead of performing a scan on the table to access data. SE works

automatically and transparently and does not require any specialinstructions in your database app lications or p rograms.

About This Manual

TheINFORMIX-SE A dministrators Guide is a complete guide to the opera ting

environment of the SE database server. This manual explains how to

configure and use SE. It also explains how to use the SE utilities.

Organization of This Manual

This man ual includes the following chap ters:

s This Introdu ction p rovides an overview of the manu al, describes the

documentation conventions u sed, introduces the demonstration

database from wh ich the prod uct examp les are dr awn , describes the

ASCII and PostScript error message files, and lists the new features in

SE, Version 7.2.

s Chap ter 1, Installation and Initial Configuration,provides

background information on planning and configuring an SE system.


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Types of Users

s Chapter 2, INFORMIX-SE System Architecture, describes the SE

program files and system files and the perm issions on d atabase filesand d irectories.

s Chap ter 3, Basic Administration and Maintenance, describes disk

usage and the maintenan ce of data integrity.

s Chap ter 4, INFORMIX-SE Indexing, describes the organization,

structure, and format u sed to index ISAM files.

s Chapter 5, Symp toms and Solutions,provides tips on

troubleshooting.

s Chapter 6, INFORMIX-SE Utilities, describes the comm and -line

utilities available for performing administrative tasks.

Types of Users

This manu al is written for SE system administrators who are responsible forthe following tasks:

s Initial installation and configura tion ofSE

s General system adm inistration an d maintenance

s Troubleshooting of system problems

Software Dependencies

This manu al assumes that you are using SE, Version 7.2, as your d atabase

server. Informix software can reside on a single compu ter or on mu ltiple

compu ters across a network. The following Informix software must reside on

your compu ter system:

s An SE database server, which you install on your compu ter or onanother comp uter over a network

s Either an Informix app lication development tool, such as

INFORMIX-New Era; an SQL application programming interface

(API), such as INFORMIX-ESQL/C; or the DB-Access utility, which

Informix ships as part of your database server


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Introduction 5

Demonstration Database

The application developmen t tool, SQL API, or DB-Access enables you to

compose qu eries, send queries to the database server, and view the resultsthat the database server returns. You can u se DB-Access to try ou t the SQL

statement d escribed in this gu ide.


The DB-Access utility, which is provid ed w ith your Informix database server

prod ucts, includ es a dem onstration database called stores7 that containsinformation abou t a fictitious wholesale sporting-goods distributor. The

sample command files that make up a d emonstration application are also

included.

Most examp les in this manu al are based on the stores7 demonstrationdatabase. The stores7 database is described in detail and its contents are

listed in App endix A of theInformix Guide to SQL: Reference.The script that you use to install the dem onstration d atabase is called

dbaccessdemo7 and is located in the $INFORMIXDIR/bin directory. Thedatabase name that you supp ly is the name given to the demonstration

database. If you do n ot supp ly a database name, the name d efaults to stores7.Use the following ru les for naming you r database:

s Nam es can have a maximum of 18 characters for INFORMIX-OnLine

Dynamic Server databases and a maximu m of 10 characters for SE

databases.

s The first character of a name mu st be a letter or an und erscore (_).

s You can u se letters, characters, and un derscores (_) for the rest of the

name.

s DB-Access makes no d istinction between upp ercase and lowercase

letters.

s The database name must be unique.
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When you run dbaccessdemo7, you are, as the creator of the database, the

owner and Database Administrator (DBA) of that d atabase.

If you install your Informix database server according to the installation

instructions, the files that constitute the dem onstration d atabase are

protected so that you cannot m ake any changes to the original database.

You can run the dbaccessdemo7 script again w henever you want to workwith a fresh d emonstration d atabase. The script prompts you w hen the

creation of the database is comp lete and asks if you w ould like to copy thesamp le comm and files to the cur rent d irectory. Enter N if you have m ade

changes to the sample files and do not want them replaced w ith the original

versions. Enter Y if you w ant to copy over the samp le command files.

To create and populate the stores7 demonstrat ion database

1. Set the INFORMIXDIR environment variable so that it contains the

name of the directory in w hich you r Informix produ cts are installed.2. Set INFORMIXSERVER to the nam e of the defau lt database server.

The name of the default database server mu st exist in the

$INFORMIXDIR/etc/sqlhosts file. (For a full description ofenvironment variables, see Chapter 4 of theInformix Guide to SQL:

Reference.) For information about th e sqlhosts file, refer to Thesqlhosts File on page 1-12 of this man ual.

3. Create a new d irectory for the SQL command files. Create the

d irectory by entering the following comm and :

mkdir dirname

4. Make the new d irectory the current d irectory by entering the

following comm and :

cd dirname
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Introduction 7


5. Create the dem onstration d atabase and copy over the samp le

comm and files by entering the dbaccessdemo7 command.To create the da tabase without logging, enter the following

command:

dbaccessdemo7 dbname

To create the dem onstration d atabase with logging, enter the

following comm and :

dbaccessdemo7 -log dbnamedbaccessdemo7 -log dbname -dbspace dbspacename

If you a re using SE, a subdirectory called dbname.dbs is created inyour cur rent directory and the database files associated with stores7are placed there. You will see both data (.dat) and index (.idx) files inthe dbname.dbs directory. (If you specify a dbspace nam e, it isignored.)

To use the database and the command files that have been copied to

your d irectory, you mu st have UNIX read an d execute p ermissions

for each directory in the p athname of the directory from w hich you

ran the dbaccessdemo7 script. Check with your system ad minis-trator for more information about operating-system file and

directory permissions. UNIX perm issions are discussed in Chapter 2

of this manu al.

6. To give someone else the permissions to access the comm and files in

your d irectory, use the UNIX chmod command.

7. To give someone else access to the d atabase that you have created,

grant them the app ropriate privileges using the GRANT statement.

To revoke p rivileges, use the REVOKE statement. The GRANT an d

REVOKE statements are described in Chap ter 1 of theInformix Guide

to SQL: Syntax.
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New Features of This Product

New Features of This ProductThe Introd uction to each Version 7.2 prod uct manual contains a list of new

features for that produ ct. The Introduction to each manu al in the Version 7.2

Informix Guide to SQL series contains a list of new SQL features.

A comp rehensive list of all of the new features for Version 7.2 Informix

prod ucts is in the Release Notes file called SERVERS_7.2.

This section highlights the major new features imp lemented in Version 7.2 of

INFORMIX-SE:

s Global Language Sup port (GLS)

The GLS feature lets Informix Version 7.2 produ cts hand le different

languages, cultu ral conventions, and code sets. GLS functionality

sup ersedes the functionality of Native Langu age Sup por t (NLS) and

Asian Language Support (ALS). GLS eliminates the need to d istin-

guish between internationalized versions of Informix software.

s Multibyte filenames

SE can generate m ultibyte filenames for the following types of files:

u Database nam es for SE (.dbs)

u Table names for SE (.dat, .idx)

s Multibyte-character sup por t for SE utilities

The secheck and selog utilities provide mu ltibyte-character suppor tfor table names and log filenames.

ConventionsThis section d escribes the conventions tha t are u sed in this man ual. By

becoming familiar with these conventions, you w ill find it easier to gather

information from this and other volumes in the documentation set.

The following conven tions are covered:

s Typograph ical conventionss Icon conventions

GLS


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Introduction 9

Typographical Conventions

s Command-line conventions

s Sample-code conventions

Typographical Conventions

This manual u ses a standard set of conventions to introdu ce new terms,

illustrate screen d isplays, describe comm and syntax, and so forth. The

following typ ographical conventions are used throughou t this manual.

Tip: When you are instructed to enter characters or to execute a command,immediately press RETURN after the entry. When you are instructed to type the

text or to press other keys, no RETURN is required.

Convention Meaning

italics Within text, new terms and emphasized w ords are printed initalics. Within syn tax diagram s, values that you are to specifyare prin ted in italics.

boldface Identifiers (nam es of classes, objects, constants, events,functions, program variables, forms, labels, and reports),environm ent variables, da tabase names, table names, colum nnames, menu items, comman d n ames, and other similar termsare printed in boldface.

monospace Information that the p roduct d isplays and information that youenter are printed in a m onospace typeface.

KEYWORDAll keyword s appear in upp ercase letters.

This symbol indicates the end of produ ct- or p latform-specificinformation.


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Icon Conventions

Icon Conventions

Throughout the documentation, you w ill find text that is identified by several

d ifferent typ es of icons. This section describes these icons.

Comment Icons

Comm ent icons identify three types of information, as described in the

following table. This information is always disp layed in italics.

Compliance Icons

Comp liance icons ind icate paragraph s that provide guidelines for comp lying

with a standard.

These icons can ap ply to a row in a table, one or more paragraphs, or an entiresection. A symbol ind icates the end of the comp liance information.

Icon Description

Identifies paragrap hs that contain vital instructions,cautions, or critical information.

Identifies paragrap hs that contain significant informationabout th e feature or operation that is being described.

Identifies paragrap hs that offer add itional details orshortcuts for the fun ctionality that is being d escribed.

Icon Description

Identifies information that is specific to a GLS-compliantda tabase or application.

GLS


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Introduction 11

Command-Line Conventions


SE sup por ts a variety of command -line options. You enter these command s

at the operating-system promp t to perform certain fun ctions in SE.

This section defines and illustrates the format of the comm and s that are

available in SE and other Informix products. These commands have their

own conventions, wh ich might include alternative forms of a comm and ,

required and optional parts of the comm and , and so forth.

Each d iagram d isplays the sequences of required and op tional elements tha t

are valid in a comm and . A diagram begins at the up per left with a command .

It ends at the up per r ight w ith a vertical line. Between these points, you can

trace any path that d oes not stop or back up . Each path d escribes a valid form

of the comm and . You m ust supp ly a value for words that are in italics.

You m ight encounter one or more of the following elements on a command -

line p ath.

Element Description

command This required element is usually the product name orother short w ord that invokes the produ ct or calls thecompiler or preprocessor script for a comp iled Informixprod uct. It might app ear alone or precede one or more

options. You m ust sp ell a comman d exactly as show nand mu st use lowercase letters.

variable A word in italics represents a value that you mu stsup ply, such as a database, file, or program nam e. A tablefollowing the diagram explains the value.

-flag A flag is usually an abbreviation for a function, menu, oroption name or for a compiler or preprocessor argum ent.

You m ust enter a flag exactly as shown , includ ing thepreceding hyph en.

.ext A filename extension, such as .sql or .dbs, might followa variable that represents a filename. Type th is extensionexactly as show n, immed iately after the nam e of the fileand a period . The extension might be optional in certainproducts.

(1 of 2)


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(.,;+*-/ ) Punctuation and mathematical notations are literalsymbols that you m ust enter exactly as show n.

' ' Single quotes are literal symbols that you mu st enter asshown.

A reference in a box represents a subd iagram on thesame page (if no page is sup plied) or another page.

Imagine that the subdiagram is spliced into the maindiagram at this point.

A shaded op tion is the default. If you d o not explicitlytype th e option, the d efault w ill be in effect unlessyou choose another option.

Syntax enclosed in a pair of arrows ind icates that th is isa subdiagram.

The vertical line is a terminator and indicates that thestatement is complete.

A branch below the ma in line ind icates an optional path .(Any term on the m ain path is required, un less a branchcan circum vent it.)

A loop indicates a path th at you can repeat. Punctuationalong the top of the loop ind icates the separator sym bolfor list items, as in this examp le.

A gate ( ) on a path indicates that you can only use

that p ath the indicated nu mber of times, even if it is partof a larger loop. Here you can specify size no more thanthree times within this statement segment.

Element Description

(2 of 2)

Privilegesp. 5-17

Privileges

ALL

NOT

IN

variable

,

3 size

, 3


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Introduction 13


Figure 1 shows the flow of the secheck utility command .

To construct a correct command , start at the top left with the command

secheck. Then follow the diagram to the right, includ ing the options tha t you

want. The elements in the d iagram are case sensitive.

To read the example command-line diagram

1. Type the w ord secheck.

2. Choose either the lower path or the up per path.

3. When you choose the lower p ath, you mu st type -V. That br ings you

to the terminator and comp letes the secheck comm and . Press

RETURN to execute the command .4. When you choose the u pp er path , take the following steps:

a. You can choose -n or -y, but not both.

b. You can choose -q.

c. You can choose -l.

d. You can choose -s.

e. Sup ply a filename.

After you choosefilename, you come to th e terminator. Your

comm and is complete.

5. Press ENTER to execute the comm and .

Figure 1An Example Command-Line Diagram

secheck filename

-y

-n -q

-V

-l -s


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Sample-Code Conventions

Sample-Code Conventions

Examples ofSQL code occur throughou t this man ual. Except where noted ,

the code is not specific to any single Informix app lication developmen t tool.

If only SQL statements are listed in the examp le, they are not d elimited by

semicolons. To use this SQL code for a specific product, you must apply the

syntax ru les for that prod uct. For example, if you a re using the Qu ery-

language option ofDB-Access, you m ust d elimit multiple statements w ith

semicolons. If you are u sing an SQL API, you must use EXEC SQL and a

semicolon (or other approp riate delimiters) at the start and end of each

statement, respectively.

For instance, you m ight see the code in the following example:

CONNECT TO stores7...DELETE FROM customer

WHERE customer_num = 121...COMMIT WORKDISCONNECT CURRENT

Dots in the example ind icate that more code wou ld be ad ded in a full appli-

cation, but it is not necessary to show it to describe the concept beingdiscussed.

For detailed d irections on using SQL statements for a par ticular ap plication

development tool or SQL API, see the manu al for your p roduct.

Addit ional Documentat ionThe SE documentation set includ es printed manuals, on-line m anuals, and

on-line help.

This section describes the following pieces of the d ocumen tation set:

s Printed documentation

s On-line documentation

s Related read ing


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Introduction 15

Printed Documentation

Printed Documentation

The following printed manuals are included in the SE documentation set:

s The UN IX Products Installation Guide contains instructions for

installing Informix products on comp uters that run the UNIX

operating system. Keep th is guide w ith your UNIX software

docum entation for easy reference.

s The Guide to GLS Functionalitycontains information on the langu age-

related topics of Global Language Sup por t (GLS).

s TheInformix Migration Guide describes the procedu res to use wh en

you migrate existing Informix databases to and from SE, Version 7.2.

This manu al includes information on preparing you r host system to

supp ort the new features provided by SE 7.2.

s If you have never used Structured Qu ery Language (SQL) or an

Informix app lication developmen t tool, read theInformix Guide toSQL: Tutorial. The manu al provides a tutorial on SQL as it is imp le-

mented by Informix produ cts. It describes the fund amental ideas

and terminology that are used w hen planning, using, and imple-

menting a relational database.

s A compan ion volume to the Tutor ial, the Informix Guide to SQL:

Reference, provides reference information on the types of Informix

databases that you can create, the data types that are sup ported inInformix produ cts, system catalog tables that are associated with the

database, environment variables, and the SQL utilities. The m anu al

also provides a detailed d escription of the stores7 demonstrationda tabase and contains a glossary.

s An additional comp anion volum e to the Tutor ial, theInformix Guide

to SQL: Syntax, provides a d etailed d escription of all the SQL state-

ments supported by Informix products. The manual also provides a

detailed d escription of Stored Procedu re Langu age (SPL) statements.

s TheDB-A ccess User M anual describes how to invoke the DB-Access

utility to access, modify, and retrieve information from SE relational

databases.

s When errors occur, you can look them u p by number and learn their

causes and solutions in theInformix Error M essages man ual. If you

prefer, you can look up the error m essages in the on-line message filethat is described later in this introdu ction and in the Introdu ction to

theInformix Error M essages manual.

GLS
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On-Line Documentation

On-Line Documentation

Several d ifferent types of on-line d ocumen tation are available:

s On-line documentation and help

s On-line error m essages

s Release notes, documentation notes, and machine notes

Error Message Files

Informix software products provide ASCII files that contain all of the

Informix error messages and their corrective actions. To read the error

messages in the ASCII file, Informix prov ides scripts that let you d isplay error

messages on th e screen (finderr) or pr int formatted error m essages (rofferr).For a detailed d escription of these scripts, see the Introduction to theInformix

Error Messages manual.The optional Informix Messages and Corrections produ ct provides

PostScript files that contain the error messages and their corrective actions. If

you h ave installed th is produ ct, you can p rint the PostScript files on a

PostScript pr inter. The PostScript error messages are d istributed in a nu mber

of files of the format errmsg1.ps , errmsg2.ps , and so on. These files arelocated in the $INFORMIXDIR/msg directory.
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Introduction 17

Related Reading

Release Notes, Documentat ion Notes, Machine Notes

In addition to th e Informix set of manu als, the following on-line files, located

in the $INFORMIXDIR/release/en_us/0333 directory, might supp lement theinformation in th is manu al:

Please examine these files because they contain v ital information aboutapplication and performance issues.

Related Reading

For ad ditional technical information on database man agement, consult the

following books. The first book is an introd uctory text for readers who arenew to database management, while the second book is a more complex

technical work for SQL programm ers and database administrators:

s An Introduction to Database Systems by C. J. Date (Ad dison-Wesley

Publishing, 1994)

s Database: A Primerby C. J. Date (Ad dison-Wesley Publishing, 1983)

On-line File Purpose

Documentation

notes

Describes features that are not covered in th e manu als or that

have been m odified since pu blication. The file that contains thedocum entation notes for this prod uct is called SEDOC_7.2.

Release notes Describes feature differences from earlier versions of Informixprod ucts and how these differences might affect currentprod ucts. This file also contains information abou t any know nproblems and their workarou nd s. The file that contains therelease notes for Version 7.2 of Informix database serverprod ucts is called SERVERS_7.2. The release notes also contain asection on limits that describes the maximum values for SE.

Machine notes Describes any special actions that are required to configure anduse Informix products on you r compu ter. Machine notes arenam ed for the prod uct that is described. The machine notes filefor SE is SE_7.2.


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Compliance with Industry Standards

To learn more about th e SQL language, consider th e following books:

s A Guide to the SQL Standardby C. J. Date with H. Darw en (Add ison-

Wesley Publishing, 1993)

s Understanding the New SQL: A Complete Guide by J. Melton and

A. Simon (Morgan Kaufmann Pu blishers, 1993)

s Using SQL by J. Groff and P. Weinberg (Osborne McGraw -Hill, 1990)

TheINFORMIX-SE A dministrators Guide assum es that you are familiar with

your compu ter operating-system. If you have limited UNIX system

experience, consult your operat ing system manu al or a good introductory

text before you read this man ual. The following texts provide a good intro-

du ction to UNIX systems:

s Introducing the UNIXSystem by H . McGilton and R. Morgan

(McGraw-Hill Book Company, 1983)

s Learning the UNIXOperating System by G. Todino, J. Stran g, andJ. Peek (OReilly & Associates, 1993)

s A Practical Guide to the UNIXSystem by M. Sobell

(Benjamin/ Cum mings Publishing, 1989)

s UNIX for People by P. Birns, P. Brown, and J. Muster (Prentice-Hall,

1985)

s UNIXSystem V: A Practical Guideby M. Sobell (Benjamin/ Cum mingsPublishing, 1995)

Compliance with Industry Standards

The American National Stand ards Institute (ANSI) has established a set of

indu stry standards for SQL. Informix SQL-based p rodu cts are fully comp liant

with SQL-92 Entry Level (published as ANSI X3.135-1992), wh ich is id entical

to ISO 9075:1992 on INFORMIX-OnLine Dynam ic Server. In addition, many

features of OnLine comp ly with the SQL-92 Interm ediate and Full Level and

X/Open CAE (comm on app lications environment) standards.


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Introduction 19

Informix Welcomes Your Comments

Informix SQL-based products are compliant with ANSI SQL-92 Entry Level

(published as ANSI X3.135-1992) on INFORMIX-SE with th e followingexceptions:

s Effective checking of constra ints

s Serializable transactions

Informix Welcomes Your Comments

Please let us know wh at you like or dislike about ou r manu als. To help us

with future versions of our manu als, please tell us about an y corrections or

clarifications that you wou ld find useful. Write to us at the following add ress:

Informix Software, Inc.

SCT Technical Pu blications Depar tmen t4100 Bohannon Drive

Menlo Park, CA 94025

If you prefer to send electronic mail, our ad dress is:

[email protected]

Or, send a facsimile to the Informix Technical Publications Depar tmen t at:

415-926-6571

Please include the following information:

s The nam e and version of the manual that you are using

s Any comm ents that you have about the manual

s

Your name, add ress, and phone num berWe appreciate your feedback.


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1Chapter

Installation and InitialConfiguration

Defining a Database Management System . . . . . . . . . . . 1-3

Planning for SE . . . . . . . . . . . . . . . . . . . . 1-4Configuring Hardware . . . . . . . . . . . . . . . . 1-4

Placing Active Tables and Files on the Disk . . . . . . . . . 1-4

Considering SE Limits . . . . . . . . . . . . . . . . 1-5

Installing SE . . . . . . . . . . . . . . . . . . . . . 1-6

Preparing SE Connections . . . . . . . . . . . . . . . . 1-6Understanding Version 7.2 SE Configurations . . . . . . . . 1-7

Setting Environment Variables . . . . . . . . . . . . . 1-8

Understanding the Communication Files . . . . . . . . . . 1-9

Network Communication Files . . . . . . . . . . . . 1-10Network Security Files . . . . . . . . . . . . . . . 1-10

The sqlhosts File . . . . . . . . . . . . . . . . . 1-12Build ing the sqlhosts File . . . . . . . . . . . . . . . 1-12

The dbservername Field . . . . . . . . . . . . . . 1-13The nettype Field . . . . . . . . . . . . . . . . . 1-13The hostname Field . . . . . . . . . . . . . . . . 1-15The servicename Field . . . . . . . . . . . . . . . 1-16Relationships Am ong N etwork-Connection Files for

TCP/ IP . . . . . . . . . . . . . . . . . 1-17

Examples of Client/ Server Connections . . . . . . . . . . 1-18Local Connections with Pipes . . . . . . . . . . . . 1-19Netw ork Connections with Version 7.2 Products . . . . . . 1-20Local-Loopback Connections with Version 7.2 Products . . . 1-22

Connecting with Different Versions . . . . . . . . . . . . 1-26

Local Conn ections with Version 4.11 or 5.x ClientApplications . . . . . . . . . . . . . . . . 1-26

Network Connections with INFORMIX-NET . . . . . . . 1-28


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1-2 INFORMIX-SE Administrators Guide

Network Connections with 5.x INFORMIX-NET Relay

Module . . . . . . . . . . . . . . . . . 1-29Network Connections with the Version 7.2 Relay Modu le . . . 1-32

Starting the sqlexecd Daemon . . . . . . . . . . . . . . 1-35

Using an NFS-Mounted Directory . . . . . . . . . . . . 1-37

How Does a Clien t App lication Connect to a Da tabase Server? . . . . 1-38


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Installation and Initial Configuration 1-3

Imp lementing a database management system (DBMS) requ ires makingmany d ecisions, such as where to store the data, how to access the data, and

how to p rotect the data. How you implement the DBMS can great ly affect theperformance of database operations. For examp le, the p hysical organization

of data and optimization performed by the DBMS directly affect the speed of

retrievals from and up dates to tables.

This chap ter explains the issues that are involved in setting up INFORMIX-SE.

You can u se this chap ter as background to help you understand the effects of

the choices that you m ake as anSE

administrator.This chap ter also d iscusses SE connectivity and commu nication as well as the

contents of the sqlhosts file.

Defining a Database M anagement System

You can d ivide a DBMS into the following parts:

s A data language, which serves as the user interface to the DBMS

s A database server, which takes the data definition an d data manipulation

language requests and p erforms the requested op erations

Database users instruct the DBMS to perform queries and other operations on

a database using language that the DBMS understands. Informix applicationdevelopment tools and SQL APIs use a database definition and man ipulation

language that is an extension of the ANSI standard SQL to send instructions

to the d atabase server.


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Planning for SE

Planning for SEPlanning can help you avoid costly and time-consuming m istakes. For

example, before you install the software, consider wh ere to locate it so that

everybody who need s to access it can do so.

After you decide where to locate the prod uct, think about the p lacement of

the database and its associated tab les. Do you want to p lace your tables on

different devices? Do you w ant to put your transaction log or aud it trails onseparate d isks? Also consider the comp uter itself. Can it suppor t the mem ory

requiremen ts ofSE? Can it support the number of open files, locks, and u sers

that the app lication requires? In ad dition, you mu st think abou t m aintenance

plans. Prepare a backup schedule. Decide w here to keep the tapes.

Configuring HardwareIf you p artitioned your disks before you began p lanning your SE system,

examine the physical layout of your d isk and verify that the partition in

wh ich you wan t to load your Informix produ cts is large enough to contain

the prod uct software. (Informix does not require you to place the prod uct

software in the same d irectory as the data.)

Placing Active Tables and Files on the Disk

A database server that uses the UNIX file system cannot transfer data d irectly

from memory to disk. The intermed iate transfer to and from the operating-

system bu ffer increases the time for the tran sfer. Although intermed iate

transfer does not always create a performance bottleneck on a database with

mod erate activity, your m ost imp ortant d esign goal must be to minimize thetime required for disk inpu t/ output (I/ O).

Keep you r most active tables on separate d isk devices to redu ce contention.

Using separate d isk devices reduces competition for disk access wh en joins

form am ong high-demand tables.

Because transaction logs and aud it trails have h igh rates of activity, you m ust

give them pr iority in d isk placement. Ideally, designate the fastest d evices orthe most central areas of the d isk to hold the transaction logs and aud it trails.


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Considering SE Limits

Remem ber the following points as you p lan the layout for your SE data:

s How you p osition d ata on d isk d evices can minimize head

movement.

s The innermost d isk partitions generally have the fastest access

timesuse th em for frequen tly accessed tables or logs.

s SE tables cannot span p artitions. Think carefully about wh ere you

decide to pu t tables. When a table fills a partition, you must d o one

of the following p rocedu res:u Move the table to a larger par tition.

u Back up the d ata, increase the size of the partition, and restore

the data.

s SE indexes (.idx files) autom atically reside on the same partition asyour .dat files.

s

Transaction logs and aud it trails grow as you p rocess transactionsagainst the database.

Considering SE Limits

Consider th e following limits ofSE wh en you install the product:

s

The maximum row size (32,511 bytes)s The maximum number of open SE tables (255)

s The maximum nu mber of locks per table (opera ting-system-

dependent)

Because SE takes advantage of some of the operating-system facilities that

UNIX provides, it also incurs some of the limits that UNIX imposes. The

nu mber of open files that you r operating system allows represents one suchlimit. You can increase the value of the following UNIX kernel parameters to

improve SE performance (although these mod ifications do not alter the SE

limitations just listed):

s The num ber of locks

s The num ber of open files

s The nu mber of inodes (an operating system entity u sed to u niquely

identify a file)


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Installing SE

Installing SEInstallation refers to the p rocess of load ing the p rodu ct files onto you r UNIX

system and running the installation script to correctly set up the produ ct files.

Some of the specific steps that you should follow as par t of your installation

depend on your environment. See the UN IX Products Installation Guide,

Version 7.2, for instru ctions about installing the Version 7.2 SE database

server.

Preparing SE Connections

Before you can u se SE with a client app lication, you m ust first un derstand the

following topics:

s Configuring INFORMIX-SE, Version 7.2, for local and remote

connections

s Setting your environment variables

s Establishing commu nication

s Building the sqlhosts file

s Connecting Informix Version 7.2 client app lications to Version 7.2 SEdatabase servers

s Connecting Informix Version 4.1 or Version 5.x client ap plications to

Version 7.2 SE database servers

s Starting the sqlexecd daemon

s Using NFS-mounted directories

The UN IX Products Installation Guide suggests that you create the d irectory/usr/informix for your Informix prod ucts. For the examp les in the followingsections, it is assumed th at you have installed the Informix Version 4.1 or 5.x

products in the /usr/informix directory, and th at you have installed theInformix Version 7.2 produ cts in the /usr/version7/informix directory.However, when you establish local connections using unnamed p ipes, you

mu st install client and server prod ucts in the same d irectory.
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Understanding Version 7.2 SE Configurations

Understanding Version 7. 2 SE Configurat ions

You m ust u nd erstand local and network configu rations before you establish

communication.

A local client/ server configu ration exists when a client prod uct connects to a

database server on the same compu ter. A remote client/ server configuration

exists when a client prod uct that resides on one comp uter establishes a

connection across a network to a d atabase server that resides on anoth er

computer.

Figure 1-1 illustrates the compatibility between client tools and a local

Version 7.2 SE database server.

Figure 1-1Client/Server Configurations for Client Products Connecting

to a Local Version 7.2 SE Database Server

Client Local SE Database Server, Version 7.2

Version 4.1 ESQL/ C,ESQL/ COBOL

Sup ported, but mu st use the Version 7.2 RelayModu le and Version 4.1 syntax

Version 5.x ESQL/ C,ESQL/ COBOL,

ESQL/ FORTRAN

Sup ported, but mu st use the Version 7.2 RelayModu le and Version 5.x syntax

Version 6.x ESQL/ C,ESQL/ COBOL

Sup ported , but cannot use syntax specific toVersion 7.2 products

Version 7.2 ESQL/ C,

ESQL/ COBOL

Supported


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Setting Environment Variables

Figure 1-2 illustrates the compatibility between client prod ucts and a remote

Version 7.2 SE database server.Figure 1-2

Client/Server Configurations for Client Products Connectingto a Remote Version 7.2 SE Database Server

Setting Environment Variables

You must set certain UNIX and Informix environment variables correctly for

your Informix prod ucts to work. These environmen t variables are

documented in theInformix Guide to SQL: Reference and the Guide to GLS

Functionality. Pay par ticular attention to the following environm ent variables:

Client Remote SE Database Server, Version 7.2

Version 4.11

INFORMIX-SQL,INFORMIX-4GL

Sup ported , but must establish connection using

Version 4.1 or 5.x INFORMIX-NET or the Version 7.2Relay Modu le. The Version 7.2 Relay Modu le is anintegral part of every Informix Version 7.2 databaseserver. Must also use Informix Version 4.1 syntax.

Version 5.x ESQL/ C,ESQL/ COBOL,ESQL/ FORTRAN

Sup ported , but must establish connection usingVersion 5.x INFORMIX-NET or the Version 7.2 RelayModule. The Version 7.2 Relay Modu le is an integralpart of every Informix Version 7.2 database server.Must also use Informix Version 5.x syntax.

Version 6.x ESQL/ C,ESQL/ COBOL

Sup ported , but cannot use syntax specific toVersion 7.2 produ cts

Version 7.2 ESQL/ C,ESQL/ COBOL

Supported

DBPATH identifies directories and d atabase servers that

contain databases.

INFORMIXDIR specifies the directory where you install your prod uct

files.

INFORMIXSERVER specifies the nam e of the default database server.

INFORMIXSQLHOSTS specifies the full pathn ame and filenam e of a file that

contains connectivity information (optional).
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Understanding the Communication Files

The Global Langu age Sup port (GLS) feature ofSE lets you u se non-English

characters, monetary conventions, and collating sequences. If you are u sing

the GLS features ofSE, you need to set the GLS-related env ironment variables,

wh ich are d ocum ented in Chap ter 5 of the Guide to GLS Functionality.


The communication files contain information necessary for client applications

and da tabase servers to communicate with one anoth er. The files that are

associated w ith network communication fall into the following group s:

s Network communication files: /etc/hosts an d /etc/services (usedonly for the TCP/ IP network protocol)

s Netw ork secur ity files

s $INFORMIXDIR/etc/sqlhosts

Of these files, you maintain only the $INFORMIXDIR/etc/sqlhosts file. The

UNIX system (or network) administrator, or the end u ser (in the case of somenetwork security files), manages the other files.

Important: For the remainder of this chapter, $INFORMIXDIR/etc/sqlhosts isreferred to as thesqlhosts file.

INFORMIXTERM specifies whether to use the termcap file or terminfo

directory (optional).PATH find s executable files.

SQLEXEC is required for some network configurations.

SQLRM is required for some network configurations.

SQLRMDIR is required for some network configurations.

TERM enables your client p rodu ct to recognize and

comm unicate with the terminal you are u sing .

Sometimes you mu st also set TERMCAP an dTERMINFO. See you r UNIX system administrator for

details.

GLS


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Network Communication Files

The network ad ministrator maintains the network commu nication files. You

use information from /etc/hosts and /etc/services for the sqlhosts file wh enyou prepare the TCP/ IP network connections. For IPX/ SPX network connec-

tions, you need the name of the N ovell NetWare configurat ion file. Also, you

need to w ork closely w ith the network ad ministrator to make sure you are

using accurate information.

For information about these files, refer to the systems m anu als for you rinstallation and to the UNIX man pages for hosts an d services.

Network Security Files

A client app lication cannot connect to a remote da tabase server un less the

user has the proper access permission. Therefore, you m ust know abou t the

imp lications of the network security files (/etc/passwd, ~/.netrc,/etc/shadow, /etc/host.equiv, ~/.rhosts) on interhost commu nication(communication between host computers).

Informix prod ucts follow stand ard UNIX security procedures, governed by

information contained in the network secur ity files. For information about

these procedu res, refer to the systems manu als for your installation and to

th e UNIX man p ages hosts.equiv and netrc.


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The following methods allow you to gain access to the network:

s The trusted host method , described in the UNIX man pages forhosts.equiv an d rhosts, establishes connections betw een tru sted

host comp uters over a network. This method does not require you to

supply a p assword.

When you set up the hosts.equiv and .rhosts files on the databaseserver host, you usu ally want to make a client host a trusted host. You

need to sp ecify the client host name in the /etc/hosts.equiv or .rhosts

file on the database server host. How ever, on some networks, thehost name that the network u ses to refer to that comp uter might not

be exactly the same as the host name that the computer u ses to refer

to itself. For example, the network host name m ight contain the full

dom ain name, as shown in the following examp le:

viking.informix.com

But the computer m ight refer to itself using the local host nam e

shown in the following example:

viking

If this occurs, make su re that you specify both host nam es in your

/etc/host.equiv an d .rhosts files.

s INFORMIX-NET PC, INFORMIX-NETforWindows, INFORMIX-NETfor

Macintosh, and INFORMIX-NETforOS/2 promp t you to enter a

password wh en you attempt to establish a network connection.s The SQL CONNECT statement in an Informix SQL API, such as

INFORMIX-ESQL/C or INFORMIX-ESQL/COBOL, allows you to

specify a password for establishing a netw ork connection. How ever,

you cannot use an SQL CON NECT statement to specify a passw ord in

DB-Access.

s The .netrc file holds password information u sed to establish

connections to remote hosts. Refer to th e UNIX man pages forinformation on how to use netrc.


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Building the sqlhosts File

The sqlhosts File

The $INFORMIXDIR/etc/sqlhosts file is the connectivity file. It contains infor-

mation that enables an Informix client app lication to connect to any Informix

database server on the network. It specifies the database server name, the

type of connection, the nam e of the host computer, and the service nam e.

You m ust p repare the sqlhosts file even if the client ap plication and the SE

database server reside on the same comp uter. The sqlhosts file is described

in Building th e sqlhosts File below.

The sqlhosts file has one entry (one line) for each type of p otential connection

from a client app lication to a d atabase server. When you use a remote

connection, an sqlhosts file must reside on the client compu ter and thedatabase server computer.

The client app lication expects to find the sqlhosts file in the

$INFORMIXDIR/etc directory; however, you can change this location or thename of the file with the INFORMIXSQLHOSTS environment var iable. Formore information on this environment variable, refer to Chap ter 4 of the

Informix Guide to SQL: Reference.


Figure 1-3 shows an example ofsqlhosts fields. The next four sectionsprovide detailed information about the following fields:

s Database servername field

s Netw ork protocol field

s Hostname field

s Servicename field

You can ed it the sqlhosts file with any convenient text ed itor. The en tries inthe first three fields can include any p rintable character but not an up percase

character, a field d elimiter, a new -line character, or a commen t character. The

entries in the fourth field can also include up percase characters. You delimit

the fields show n in Figure 1-3 with spaces or tabs.


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Figure 1-3Example of Fields in an sqlhosts File

The dbservername Field

The dbservername field contains the database server nam e that theINFORMIXSERVER environm ent var iable specifies. Each database server on

the netw ork mu st possess a un ique nam e that cannot exceed 18 characters.

The nettype Field

The nettype field, a string of eight letters comp osed of three subgrou ps,

describes the type of connection that a client can u se to connect to the

database server. Figure 1-4 illustrates the nettype field.

dbservername nettype hostname servicename

valley_se setlitcp valley valley_service

river_se seipcpip river sqlexec

Figure 1-4

Format of thenettype Fieldd d i i i p p p

Databaseserver product

Interface type Network protocol


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The following list describes the subfields ofnettype and the valid values

allowed for SE, as show n in Figure 1-5:s The first two letters represent the database server p rodu ct:

u The se represents INFORMIX-SE.

u The on represents the INFORMIX-OnLine Dynamic Server (not

used in this situation).

u The gw represents INFORMIX-Gateway withDRDA (not used in

this situation).s The midd le three letters represent the internal program ming

interface connection typ e that enab les comm un ication:

u The ipc represents a UNIX-based interprocess communication (IPC)

connection th at is used on ly for local loopback connections.

u The tli represents a transport-level interface (TLI) netw ork interface

that is u sed for local-loopback and remote-host connections.

u The soc represents a socket type ofnetwork interface that is used

for local-loopback and remote-host connections.

The installation package for this product contains the Machine Notes

file, SE_7.1, that discusses the network interface that your p latform

supports.

s The final three letters represent the sp ecific IPC mechanism or the

network protocol:

u The pip represents unnamed pipes. Usepip only for local

connections.

u The tcp represents the TCP/ IP protocol. Use tcp for netw ork

connections.

u The spx represents the IPX/ SPX protocol. Use spx for netw ork

connections.The network interface describes the behavior between the compu ter

and the netw ork. The netw ork protocol describes the behavior of the

network itself.


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Figure 1-5 shows the valid va lues for nettype used w ith SE.

Figure 1-5Valid nettype Values for SE

The hostname Field

The hostname field specifies the compu ter where the da tabase serverproduct resides. When you use the TCP/ IP connection protocol, the

hostname field mu st correspond to the host-name entry in the /etc/hosts file,wh ich p rovides the network ad dress of the host comp uter. As a ru le, the

hostname entry in the /etc/hosts file is the same as the name of your

comp uter. See your network adm inistrator to determine what name is

assigned to a specific host, and m ake sure that you both agree on the

hostname field.

Figure 1-6 shows an example of the /etc/hosts fields. The host-alias field isoptional.

Figure 1-6Example of hostname Fields in an /etc/hosts File

nettype Description

seipcpip SE using unnamed pipes for local mode

setlitcp SE using TLI with TCP/IP protocol

sesoctcp SE using sockets with TCP/IP protocol

setlispx SE using TLI with IPX/SPX protocol

net address hostname host-alias

29.9.925.6 valley accounts

B ildi h lh Fil


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Informix bases its imp lementation ofIPX/ SPX on the NetWare implemen-

tation ofIPX/ SPX

. When you u se theIPX/ SPX

protocol, the hostname fieldmu st contain the nam e of the NetWare file server rather than the actual nameof the host comp uter. The imp lementation ofIPX/ SPX varies among vendors,

so refer to the vendor d ocumen tation for more details about the required

files.

The servicename Field

The interpretation of the servicename field d epends on the type of networkconnection that is specified in th e nettype field.

When you use unnam ed pipes, the servicename field m ust contain the nam eof the SE executable file, distributed as sqlexec.

When you specify a nettype field whose last three letters are tcp, theconnection is a TCP/ IP network connection. When you use the TCP/ IP

connection p rotocol, the service name mu st correspon d to a service-nam e

entry in the /etc/services file, as illustr ated in Figure 1-7. The /etc/services filetells the network software how to find the database server on the specified

host computer. It does not matter wh at service name you choose as long as

you and your network ad ministrator agree on a name.

Figure 1-7Example of servicename Field in an /etc/services File

Tip: When you are usingNIS, type ypcat services and press RETURN to verify

the services available in your domain.

When you sp ecify a nettype field w hose last three letters are spx, you sup port

an IPX/ SPX network connection. When you use the IPX/ SPX connection

protocol, the service nam e mu st match dbservername .

servicename port #/protocol service-alias

valley_service 1536/ tcp

B ildi th lh t Fil


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Relat ionships Among Network-Connect ion Files for TCP/IP

Comm on information stored in specific fields relates the sqlhosts, /etc/hosts ,

an d /etc/services files to each other for TCP/ IP connections. Figure 1-8 illus-trates the relationships among the $INFORMIXDIR/etc/sqlhosts file, the/etc/services file, and the /etc/hosts file. The servicename fields in thesqlhosts and /etc/services files match. The hostname fields in the sqlhostsan d /etc/hosts files also match.

Figure 1-8Relationships Among Network-Connection Files

/etc/hosts

net address host name host-alias29.9.925.6 hill accounts

66.9.30.62 canyon inventory

$INFORMIXDIR/etc/sqlhosts

dbservername

menlo

newyork

pittsburg

nettype

seipcpip

setlitcp

sesoctcp

hostname

valley

hill

canyon

servicename

sqlexec

se2

se3

sesoctcp

Server type Protocol

Interface

/etc/services

servicename port # /protocol service-al ias

se2 1536/ tcp

se3 1425/ tcp

Service names matchHost names match

E l f Cli t/S C ti


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Examples of Client/Server Connections


This section discusses client/ server configura tions for making connections

between an Informix Version 7.2 client and a Version 7.2 SE database server.

The following configu rations are p ossible:

s A local connection with u nnam ed pipes

s A remote (netw ork) connection

s A local loopback connection

The connection information that th is section d escribes is true for all

Version 6.0 and later clients and da tabase servers.

For information about connecting Version 7.2 SE database servers with an

Informix Version 5.x or 4.1 client, see Connecting with Different Versions

on page 1-26.

In all the configura tions in the next sections, you m ust correctly set thefollowing environm ent variables for the user:

s PATH

s TERM

s DBPATH (optional)

PATH mu st always includ e $INFORMIXDIR/bin so that the comp uter can findthe Informix prod ucts. TERM provides information to the UNIX operatingsystem so that the key set and d isplay fun ction properly. DBPATH shows the

location of databases and da tabase servers.

In the following examp les, it is assum ed that you h ave installed the Informix

Version 7.2 prod ucts in the /usr/version7/informixdirectory. In oth er words,when you perform the installation, set the INFORMIXDIR environment

variable to /usr/version7/informix.



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Local Connections with Pipes

When the client application and the SE database server reside on the same

host comp uter, the client application accesses the local da tabase server u sing

unnamed pipes, as shown in Figure 1-9.

Important: The preceding diagram is also accurate for a connection between aVersion 7.x client and a Version 6.x SEdatabase server or a Version 6.x client and a

Version 7.x SEdatabase server.

The user must set the INFORMIXDIR an d INFORMIXSERVER environment

variables to the values that are shown in Figure 1-10.

Figure 1-10Environment Variables and

Required Settings

Tip:Remember,/usr/version7/informix represents the installation directory for allInformix Version 7.2 products.

The $INFORMIXDIR/etc/sqlhosts file must include the following entry:

local_se seipcpip river sqlexec

Figure 1-9A Local

Configuration UsingUnnamed Pipes

Version 7.2

Client SE

Version 7.2Unnamed pipes

river

Environment Variable Value

INFORMIXDIR / usr/ version7/ informix

INFORMIXSERVER local_se



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The four th item in the sqlhosts entry (sqlexec) represents the name of theexecutable file for SE, as installed by the Informix installation p rocedu re.

When you do not m odify the installation, sqlexec is the executable file.

The SE database server process starts when the client executes one of the

following statements:

s CONNECT TO database_name@local_se

s CONNECT TO @local_se

Because these statemen ts represent a purely local connection, the /etc/hostsan d /etc/services files are unaffected.

Network Connections with Version 7. 2 Products

When the client app lication resides on one comp uter and the database server

resides on another comp uter, the connection is called a remote or network

configuration, as shown in Figure 1-11.

Important: The preceding diagram is also accurate for a connection between aVersion 7.x client and a Version 6.x SEdatabase server or a Version 6.x client and a

Version 7.x SEdatabase server.

Figure 1-11Network

Configuration withan Informix

Version 7.2 ClientApplication and an

INFORMIX-SE,Version 7.2,Database Server

Version 7.2Client SE

Version 7.2

sqlexecd

Version 7.2

canyon valley



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Setting Up the canyon and valley Host Computers

For the canyon compu ter, set the INFORMIXDIR an d INFORMIXSERVERenvironment variables to the values show n in Figure 1-12.


Required Settings

The sqlexecd daemon m ust be run ning. To start the daemon , you mu st log inas root and enter the following comm and :

/usr/version7/informix/lib/sqlexecd valley_se

For information about the sqlexecd daemon , refer to Starting the sqlexecdDaemon on page 1-35.

Setting Up the Communication Files

Each host computer (hilltop an d valley) must contain an sqlhosts file thatinclud es connection information associated w ith the netw ork interface and

network p rotocol that you are u sing. Figure 1-13 shows the sqlhosts fileentries for d ifferent netw ork interfaces.

Figure 1-13Network Interfaces and Associated

sqlhosts File Entries



INFORMIXSERVER valley_se

Network Interface sqlhosts File Entry

Sockets on TCP/IP valley_se sesoctcp valley valley_service

TLI interface on TCP/IP valley_se setlitcp valley valley_service



48/138



When you u se a TCP/ IP network, the /etc/hosts file must contain an entry forth e valley compu ter and the /etc/services file must contain an en try forvalley_service.

When the host computer uses the TLI network interface on an IPX/ SPX

network, the hostname field contains the n ame of the N etWare file serverinstead of the compu ter host nam e. On the display screens that are associated

with the p repara tion of the NetWare connections, the screen d isplays the

NetWare file server name in upp ercase letters; for example, NW_SVR.

However, in the sqlhosts file, you m ust enter th e name in lowercase letters;for example, nw_svr.

For an IPX/ SPX connection, the value in the servicename field can contain an

arbitrary string, but that string mu st represent a un ique name am ong the

nam es of services available on the IPX/ SPX network. In other words, you

cannot u se the string as a service nam e on any other file server on the

netw ork when that file server does not use an Informix product. You can use

th e dbservername value in the servicename field, as show n in Figure 1-14,providing that the dbservername value exists as a unique service name.

Figure 1-14Using the dbservername Value in the servicename Field

Local-Loopback Connections with Version 7. 2 Products

A network connection between a client app lication and a da tabase server on

the same comp uter is called a local-loopbackconnection. A local-loopback

connection uses network connections even thou gh the client and thedatabase server reside on the same compu ter. You can make a local-loopback

connection if your compu ter is equipped to process netw ork transactions.

Affected Field sqlhosts File Entry

servicename valley_se setlispx nw_svr valley_se



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Figure 1-15 shows a local-loopback connection between an Informix

Version 7.2 client application and a Version 7.2 SE database server. You can

think of this configu ration in the following w ays:

s The connections go outside the comp uter valley and come backinside again, as show n in Examp le A ofFigure 1-15.

s The connections remain w ithin the valley host comp uter, as shownin Examp le B ofFigure 1-15.

Tip: You can use a local-loopback connection to test network operations without aremote computer.

Important: This diagram is also accurate for a connection between a Version 7.2client and a Version 6.x SEdatabase server or a Version 6.x client and a Version 7.2

SEdatabase server.

Figure 1-15A Local-Loopback Configuration with a Version 7.2 Client

Application and Version 7.2 SE Database Server

Version 7.2

Client SE

Version 7.2

sqlexecd

Version 7.2

Client SE

Version 7.2sqlexecd

Example A

Example B

valley valley_se

valley_se

Version 7.2

Version 7.2

valley



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Setting Up the valley Host Computer

The user must set the INFORMIXDIR an d INFORMIXSERVER environmentvariables to the values shown in Figure 1-16.


Required Settings

The sqlexecd daemon m ust be running. To start the daemon, log in as rootand enter the following command :


For information about the sqlexecd daemon, refer to Starting the sqlexecdDaemon on page 1-35.


Each host computer (hilltop and valley) mu st contain an sqlhosts file thatinclud es connection information associated w ith the network interface and

network p rotocol that you are u sing. Figure 1-17 shows the sqlhosts fileentries for d ifferent network interfaces.





INFORMIXSERVER valley_se


Sockets on TCP/IP valley_se sesoctcp valley va lley_service




51/138



When you u se a TCP/ IP network, the /etc/hosts file mu st contain an en try forthe valley compu ter and the /etc/services file must contain an en try forvalley_service.

When the host comp uter uses the TLI network interface on an IPX/ SPX

network, the hostname field contains the n ame of the NetWare file serverinstead of the compu ter host nam e. On the disp lay screens that are associated

with the p reparat ion of the NetWare connections, the screen d isplays the

NetWare file server in upp ercase letters; for example, NW_SVR. How ever, in

the sqlhosts file, the name app ears in lowercase letters; for example, nw_svr.

For an IPX/ SPX connection, the value in the servicename field can contain anarbitrary string, but that string mu st represent a un ique name am ong the

nam es of services available on the IPX/ SPX network. In other words, you

cannot use the string as a service name on any other file server on the

network, even if that file server does not use an Informix produ ct. You can

use the dbservername value in the servicename field, as shown in Figure 1-18,

providing that the dbservername value exists as a un ique service nam e.

Figure 1-18Using the dbservername Value

in the servicename Field

Affected Field sqlhosts File Entry

servicename valley_se setlispx nw_svr valley_se

Connecting with Different Versions


52/138




This section shows h ow to connect an Informix Version 4.1 or Version 5.x

client app lication to an Version 7.2 SE database server. You can connect the

client and server comp onents in the following ways:

s An Inform ix Version 4.1 or 5.x client ap plication conn ects directly to

a local Version 7.2 SE database server.

s An Inform ix Version 4.11 client ap plication connects to an Inform ix

Version 7.2 database server u sing Version 4.11 INFORMIX-NET, withINFORMIX-SE or the Relay Module compon ent of an Informix

Version 7.2 da tabase server.

s An Informix Version 5.x client application connects to an Informix

Version 7.2 database server using Version 5.x INFORMIX-NET withINFORMIX-SE, a Version 5.x Relay Modu le, or the Relay Modu le

compon ent of an Informix Version 7.2 database server. For more

information about using INFORMIX-NET with INFORMIX-SE or theINFORMIX-NET Relay Mod ule, refer to theINFORMIX-NET/

INFORMIX-STARInstallation and Configuration Guide. For more infor-

mation about u sing the Relay Modu le component of a Version 7.2 SE

database server, refer to Local Connections with Version 4.11 or 5.x

Client Applications below.

Local Connect ions with Version 4. 11 or 5.x Client Applications

Figure 1-19 shows a configu ration w ith an Informix Version 4.11 or 5.x client

app lication connecting to a Version 7.2 SE database server:

Figure 1-19Local Connection

from a Version 4.11

or 5.x ClientApplication to a

Version 7.2Database Server

Version 4.11 or 5.x

ClientRelayModule

Unnamed pipes

local_se

SE

Version 7.2

hilltop

Version 7.2



53/138


Co ect g t e e t e s o s

The Version 7.2 Relay Module, a component of Informix Version 7.2 database

servers, is specifically designed to allow Inform ix Version 4.11 and 5.x client

app lications to connect to an Informix Version 7.2 database server.

For the configu ration in Figure 1-19, the user must set the INFORMIXDIR an d

INFORMIXSERVER environm ent variables to the values show n in

Figure 1-20.


Required Settings

You mu st set the SQLEXEC environment variable to the complete pathname

of the executable file for the Version 7.2 Relay Modu le.

Important: When you use unnamed pipes, the Informix Version 4.1 and 5.x clientapplication must reside in the same directory as the Informix Version 7.2 database

server.

The sqlhosts file must include the following entry:

local_se seipcpip hilltop sqlexec

The sqlhosts file belongs in th e $INFORMIXDIR/etc directory. For local

connections, the /etc/hosts an d /etc/services files remain u naffected.


INFORMIXDIR / usr/ informix

INFORMIXSERVER local_se

SQLEXEC / usr/ informix/ lib/ sqlrm



54/138


g

Network Connections with INFORMIX-NET

You can connect from an Informix Version 5.x client to a remote Version 7.2SE database server using Version 5.x INFORMIX-NET. That configu ration also

applies to an Informix Version 4.1 client connecting to an Informix

Version 7.2 database server using Version 4.1 INFORMIX-NET, or an Informix

Version 4.1 client connecting to an Informix Version 7.2 database server using

Version 5.x INFORMIX-NET. Figure 1-21 shows the configuration using

Version 5.x INFORMIX-NET.

Setting Up the hilltop and valley Host Computers

For the hilltop compu ter, set the INFORMIXDIR an d SQLEXEC environmentvariables to the values show n in Figure 1-22. For the valley compu ter, set theINFORMIXDIR environment variable to the value shown in Figure 1-22.


Required Settings

Figure 1-21A Remote Connection Using Version 5.x INFORMIX-NET

Version 5.x

Client

SE

Version 7.2

sqlexecd

hilltop

valley_se

Version 5.xINFORMIX-

NET

valley

Version 7.2

Host Computer Environment Variable Value

hilltop INFORMIXDIR / usr/ informix

hilltop SQLEXEC sqlexec

valley INFORMIXDIR / usr/ version7/ informix



55/138


g

The sqlexecd daemon m ust be running. To start the daemon, log in as rootand enter the following comm and :


For information about the sqlexecd daemon , refer to Starting the sqlexecdDaemon on page 1-35.


Each host computer (hilltop an d valley) must contain an sqlhosts file thatinclud es connection information associated w ith the netw ork interface and

network p rotocol that you are u sing. Figure 1-23 shows the sqlhosts fileentries for d ifferent netw ork interfaces.



For TCP/ IP connections, th e /etc/hosts file must contain an entry for thevalley host computer, and the /etc/services file must contain an en try forvalley_service.

Do not confuse the servicename entry for a remote connection (as illustratedin Figure 1-21) with the servicename entry for a local connection (as illus-trated in Figure 1-19). For a local conn ection, the service name indicates the

SE process as a pathn ame or a program n ame. For remote connections, the

service name in the sqlhosts file points to an entry in the /etc/services file.

Network Connections with 5.x INFORMIX-NET Relay Module

Figure 1-24 shows an Informix Version 5.x client ap plication connecting to a

remote Version 7.2 SE database server using the Version 5.x INFORMIX-NET

Relay Modu le.






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g

Important: Informix does not provide a Relay M odule with Informix Version 4.1products.

Setting Up the hilltop and valley Host Computers

For the hilltop compu ter, set the INFORMIXDIR, SQLEXEC, and SQLRMDIR

environm ent variables to the values shown in Figure 1-25. For the valleycompu ter, set the INFORMIXDIR environment variable to the value show n in

Figure 1-25.

Figure 1-25Environment Variables and Required Settings

Figure 1-24A Remote Connection Using the Version 5.x

INFORMIX-NET Relay Module

Version 5.x

Client

SE

Version 7.2

sqlexecd

valley_se

Version 5.xINFORMIX-NET RelayModule

Version 7.2

hilltop valley

Host Computer Environment Variable Value

hilltop INFORMIXDIR / usr/ informix

hilltop SQLEXEC sqlexec

hilltop SQLRMDIR $INFORMIXDIR/ lib

valley INFORMIXDIR / usr/ version7/ informix



57/138


The configu rations shown in Figure 1-21 an d Figure 1-24 do not u se the

INFORMIXSERVER environm ent variable. Only Informix Version 6.0 and

later p roducts use the INFORMIXSERVER environment variable. Because only

Informix Version 5.x products reside on the client host compu ter (hilltop),

you do not use INFORMIXSERVER.

You mu st set the SQLRM environm ent variable for the hilltop computer.Figure 1-26 shows the SQLRM environm ent variable entry for d ifferent

network interfaces.

Figure 1-26SQLRM Environment Variable Entries

The sqlexecd daemon m ust be running. To start the daemon, log in as rootand enter the following comm and :


For information about the sqlexecd daemon , refer to Starting the sqlexecd

Daemon on page 1-35.


Each host computer (hilltop an d valley) must contain an sqlhosts file that

includ es connection information tha t is associated w ith the netw ork interface

and network p rotocol that you are using. Figure 1-27 shows the sqlhosts file

entries for d ifferent netw ork interfaces.

Network Interface SQLRM Envi ronment Variable Ent ry

Sockets on TCP/IP sqlrmsoctcp

TLI interface on TCP/IP sqlrmtlitcp



58/138




The /etc/hosts file mu st contain an entry for the valley host comp uter, and the/etc/services file must contain an en try for valley_service.

Network Connections with the Version 7. 2 Relay Module

Figure 1-28 shows a configuration that connects an Informix Version 4.1 or

5.x client application to a remote Informix Version 7.2 database server using

the Version 7.2 Relay Modu le. When an Informix Version 4.11 client appli-

cation connects to an Informix Version 7.2 database server, you use the

configuration shown in Figure 1-28.



TLI interface on TCP/IP valley_se setlitcp valley va lley_service

TLI interface on IPX/SPX valley_se setlispx valley valley_service

Figure 1-28

A Remote Connection Using theVersion 7.2 Relay Module

Version 4.11 or 5.x

Client

SE

Version 7.2

sqlexecd

hilltop

valley_se

valley

RelayModule

SE orOnLine

Version 7.2

Version 7.2

Version 7.2

Connecting with Differen

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