Database Administrator's Guide

MATCHING_SEGMENT

MATCHING_SEGMENT <RENAME | DELETE | OVERWRITE | ERROR>

The segmented file logic behaved as follows when an attempt to create a new file segment encountered an existing segment with the same name:

If the existing segment matched the host file’s file ID and other attributes, then the existing segment was simply overwritten.
If the file ID did not match, then an error was returned and no more records could be added to the file.

Overwriting a matching segment could cause a problem because the existing data is simply left in place until new records overwrite the data.

In addition to different defaults, the behavior for a matching segment (i.e., segment’s file ID matches the host file’s unique ID), is quite different than for a non-matching segment. For a matching segment, if RENAME is in effect and the rename fails, then a delete is attempted. If a delete fails, then the segment is overwritten. The error option must be explicitly requested. For a non-matching segment, if either rename or delete are in effect and they fail, then an error occurs (and overwrite is not an option).

CTSTATUS.FCS entries are made when one of these unexpected segments are encountered. When a rename occurs, the segment’s name is modified by adding the hexadecimal representation of the system’s time in seconds to the end of the file name. For example,

mydata.s04

might become

mydata.s04.4465f728

where 0x4465f728 is the system time in seconds from some arbitrary starting point.

Default: RENAME