SAS 9.4 Language Reference, 6th Edition

observation numbers. Any operation that requires an observation number is not

available. There are no messages to indicate that the file has reached or exceeded the

maximum observation count.

The following list describes some of the operations and features that are limited for a

SAS data file that exceeds the maximum observation count and does not have an

index or an integrity constraint that uses an index. For a complete list, contact SAS

Technical Support.

• SAS procedures that return an observation count (such as the PRINT procedure

or the CONTENTS procedure) return a missing value, which is represented by a

period (.), for the number of observations.

• SAS procedures that depend on the observation count (for example, the SORT

procedure or the COMPARE procedure) can return unpredictable results.

• Operations that update the observation count cannot be submitted. You cannot

reset the observation count by deleting observations.

• When you request to compress a file for which the observation count is no longer

maintained, the compression percentage cannot be calculated.

• You cannot create an index or an integrity constraint.

Recovering from an Exceeded Maximum Observation Count

If a SAS data file has reached or exceeded the maximum number of observations that

can be counted and the file has an index or an integrity constraint that uses an index,

then you must take explicit action to continue processing. You can delete the index or the

integrity constraint and continue processing. However, because the file exceeds the

maximum observation count, you have limited functionality. You can use the

DATASETS procedure or the SQL procedure to delete indexes and integrity constraints.

See the Base SAS Procedures Guide or the SAS SQL Procedure User’s Guide.

If the file does not have an index or an integrity constraint that uses an index, there are

no messages to indicate that the file has reached or exceeded the maximum observation

count. However, the file has limited functionality.

Here are some ways to recover from an exceeded maximum observation count:

• If the file was created in SAS 9.2 or earlier, the observation count might have been

limited. Try re-creating the file in the current release to increase the maximum

observation count.

• Deleted observations are included in the total observation count. If the data file has

deleted observations, try re-creating it. Use a method that does not retain deleted

observations, such as the COPY procedure or the DATA step with a SET statement.

(The MIGRATE procedure retains deleted observations.)

Understanding an Audit Trail

Definition of an Audit Trail

The audit trail is an optional SAS file that you can create in order to log modifications to

a SAS data file. Each time an observation is added, deleted, or updated, information is

written to the audit trail about who made the modification, what was modified, and

when.

Understanding an Audit Trail 621