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Serious Serious
Reported By: Adam Brett
Reported On: 2/11/2014
For: Version 2.15 Build 3
# 4006 Locking Conflicts During ALTER TABLE Execution Can Cause Error #100 Internal Checksum Mismatch

When running my change scripts I would regularly receive a message "Error unable to lock [tablename] in session ..." when trying to run changes to the Attributes of a table.

However, strangely the changes actually had happened, despite the error.

Comments Comments
The scenario described above is actually harmless and won't cause an #100 error because changes to the Attributes of a table don't cause changes to the table files (just the database catalog). However, table alterations that do cause changes to the table files can still experience a locking error during the last phase of the table alteration where the checksums of the table files were updated, leaving the table files with a different internal checksum than what was saved in the database catalog for the table. This has been fixed now so that the exclusive lock on the table is held across both the catalog update and the checksum update, thus preventing this issue from occurring.

Resolution Resolution
Fixed Problem on 2/14/2014 in version 2.16 build 1

Products Affected Products Affected
ElevateDB Additional Software and Utilities
ElevateDB DAC Client-Server
ElevateDB DAC Client-Server with Source
ElevateDB DAC Standard
ElevateDB DAC Standard with Source
ElevateDB DAC Trial
ElevateDB LCL Standard with Source
ElevateDB PHP Standard
ElevateDB PHP Standard with Source
ElevateDB PHP Trial
ElevateDB VCL Client-Server
ElevateDB VCL Client-Server with Source
ElevateDB VCL Standard
ElevateDB VCL Standard with Source
ElevateDB VCL Trial