PRB: No Size Change When Dump Overlaid Over Previous Dump

  - Microsoft SQL Server version 4.2 for OS/2

SYMPTOMS

When a database dump is overlaid over a previous dump, and if the database has less data than the previous dump, the size of the dump file does not change; it changes only if the second dump is larger.

CAUSE

This behavior occurs because SQL Server uses an end-of-file (EOF) marker to close a dump device, and does not provide any feature to free up unused disk space. Therefore, as observed above, if the dump file is smaller than the previous dump file, the size of the DUMP.DAT file will remain the same.

WORKAROUND

If disk space is a consideration, rename your DUMP.DAT file(s), execute your dump procedures, and if the dump procedures are successful, delete the renamed DUMP.DAT file(s).

MORE INFORMATION

Example

Suppose the size of the OS/2 file containing a previous dump is 11,948,032. Dump the database after a month and the TESTDB.DAT file still shows 11,948,032. Then copy TESTDB.DAT to another file, delete TESTDB.DAT, and redump the database. The new TESTDB.DAT is now 10,919,936. This is because in OS/2 if you overlay a larger file with a smaller file, the overlaid file is smaller.