SAS 9.4 Language Reference, 6th Edition

Figure 28.1 Types of SAS Data Sets

SAS Data Views

(contain descriptor

information that points to

data stored elsewhere)

SAS Data Files

(contain data and

descriptor information)

Native Data Files

(formatted by SAS)

Interface Data Files

(formatted by other

software)

Native Data Views

(formatted by SAS)

Interface Data Views

(formatted by other

software)

PROC SQL Views DATA Step Views

SAS Data Sets

Understanding the Observation Count in a SAS

Data File

Definition of the Observation Count

The observation count includes both observations (rows) and deleted observations. The

maximum number of observations that can be counted for a SAS data file is 2

63

–1 or

approximately 9.2 quintillion observations. Exceeding that number is extremely unlikely

for most users.

Backward Compatibility of the Extended Observation Count

Attribute

Overview of the Extended Observation Count Attribute

In SAS 9.2 and earlier releases, the maximum observation count was much lower under

some operating environments. In SAS 9.3, an extended observation count was offered to

users with the option EXTENDOBSCOUNTER=YES. In SAS 9.4 and later releases, the

observation count is extended by default, and SAS has the same maximum observation

count under all environments.

The behavior depends on your operating environment:

• Under UNIX environments, by default the EXTENDOBSCOUNTER= option is not

set. The extended observation count feature is not necessary under 64-bit UNIX.

However, if you specify the OUTREP= option, and the data representation is not a

64-bit UNIX operating environment, then SAS automatically sets

EXTENDOBSCOUNTER=YES. SAS adds the extended observation count feature

for compatibility with environments other than UNIX where it might be necessary.

618 Chapter 28 • SAS Data Files

(Many customers specify OUTREP= when they create a data set for use in a

different environment. This practice can help you avoid the limitations of CEDA

processing.)

• Under Windows and z/OS, by default EXTENDOBSCOUNTER=YES. Files are

created with the enhanced file format and the extended observation count attribute.

When to Use the EXTENDOBSCOUNTER=NO Option

The extended observation count attribute can make data sets unusable in SAS 9.2 and

earlier releases, under certain circumstances. Here is an example of the error message:

ERROR: File MYFILES.EXTEND.Data not compatible with this SAS version.

The behavior depends on your operating environment:

• Under UNIX, if you specify OUTREP= and plan to use the file in SAS 9.2 or earlier

releases, specify EXTENDOBSCOUNTER=NO. If you do not specify OUTREP=,

then you do not need to specify EXTENDOBSCOUNTER=NO.

• Under Windows or z/OS, if you plan to use the file in SAS 9.2 or earlier releases,

specify EXTENDOBSCOUNTER=NO.

For more information, see the following:

• The EXTENDOBSCOUNTER= data set option is documented in SAS Data Set

Options: Reference.

• The EXTENDOBSCOUNTER= LIBNAME statement option is documented in SAS

Global Statements: Reference.

• The EXTENDOBSCOUNTER= system option is documented in SAS System

Options: Reference.

Viewing the ExtendObsCounter Attribute in CONTENTS Output

When you run PROC CONTENTS or the CONTENTS statement of PROC DATASETS,

you can see the ExtendObsCounter attribute in the output. If a SAS data file does not

contain the extended observation count file attribute, the ExtendObsCounter field is not

listed.

Understanding the Observation Count in a SAS Data File 619

Output 28.1 CONTENTS Procedure Output Showing ExtendObsCounter Attribute

Interactions with the Extended Observation Count

Note the following details:

• SAS functionality that copies files (such as the APPEND procedure, COPY

procedure, MIGRATE procedure, and SET statement) does not copy the extended

observation count attribute.

• In a SAS/SHARE client session, the EXTENDOBSCOUNTER= option in the

LIBNAME statement is ignored if it is specified in combination with the SERVER=

option.

Exceeding the Maximum Observation Count

SAS Processing When the Maximum Observation Count Is Reached

The observation count includes both observations (rows) and deleted observations. The

maximum number of observations that can be counted for a SAS data file is 2

63

–1 or

approximately 9.2 quintillion observations. When a SAS data file reaches the maximum

observation count, continued SAS processing depends on whether the file has an index

or an integrity constraint that uses an index.

• If the SAS data file has an index or an integrity constraint that uses an index (unique

key, primary key, and foreign key), an error message is issued when an operation

reaches the maximum observation count.

A SAS data file is not damaged when an operation attempts to exceed the maximum

observation count. However, you must take explicit action to continue processing the

file.

• If the SAS data file does not have an index or an integrity constraint that uses an

index, sequential processing continues and additional observations are accepted.

However, the file cannot store the observation count and does not maintain the

620 Chapter 28 • SAS Data Files