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Serious Serious
Reported By: Raul Sinimae
Reported On: 11/23/2020
For: Version 4.49 Build 3
# 4792 Specifying File Extensions with Tables in a Backup Can Cause Locking Issues and Corrupted Backups

I wanted to ask for your input as I'm having some rare DBISAM backup related issues - or more specifically restore related.

Issue I'm seeing looks like a truncated backup file (bkp file) which is not restorable past a certain table.

It's rare but has now happened few times over approx. 6 months (that i know of) so i'm trying to figure out what can cause this and how to prevent/recover from it.


Comments Comments
The problem was that the backup functionality was not stripping out the .dat file extensions included with the list of tables provided to the backup, and this would cause the table handling code in the backup functionality to use different lock offsets than the normal table functionality in DBISAM. The lock offsets would be different because the table would be considered different from the table without the .dat extension in the dbisam.lck lock file handling. The end result would be a backup that would execute while other sessions would still be writing concurrently to the same table files, thus resulting in a corrupted backup.


Resolution Resolution
Fixed Problem on 12/8/2020 in version 4.49 build 4


Products Affected Products Affected
DBISAM Additional Software and Utilities
DBISAM VCL Client-Server
DBISAM VCL Client-Server with Source
DBISAM VCL Standard
DBISAM VCL Standard with Source
DBISAM VCL Trial

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