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Possible causes for corrupt Connexion client local files

Symptom
  • My Connexion client local file has become corrupt.  How do I repair it?
Applies to
  • Connexion client
Resolution

Typically, running maintenance with the client's Compact/Repair utility will fix a corrupt Connexion client local file:

  1. Close all windows displaying records.
  2. Click File > Local File Manager (the file with the checkmark is your default file).
  3. Click the Compact/Repair button.
  4. Follow the prompts.

 

Why did my database become corrupt?

The information below has been adapted from a Microsoft knowledgebase article.  It references the Connexion client local bib file as this is the database that usually becomes corrupt since it is the workhorse of the client and catalogers are constantly reading, modifying, and deleting records from it.

Connexion client local bib files can become corrupt under the following conditions:

  • Network/LAN issues
  • Faulty networking hardware
  • Windows is shut down incorrectly
  • Power outage

 

Connexion client bib.db files are actually Microsoft Access databases and use Windows built-in MDAC for reading and writing.

Network/LAN issues
It’s possible for a LAN to be overworked and experience a high percentage of collisions.  Typically more than 5% collision rate can cause undesirable results under certain circumstances, such as writing to an Access database during high network congestion.

If your local bib files are stored on a network share and you experience frequent local file corruption, consult your network IT department and ask them if they can run some tests to determine RX, TX (bytes sent and received) and collision rate on your NIC (network interface card).  The problem could be related to hardware; NIC, cables, hubs or switches on the LAN that aren’t keeping up with demand and dropping packets when Connexion is trying to update the bib file after adding, editing,  or deleting records in a file.

How does this happen?
Sometimes the issue is due to a large volume of traffic on your network causing "collisions" which is when two or more computers try to use the network at the same instant.  This is commonly seen in enterprise networks, like schools and businesses during peak hours when everyone is trying to connect to the internet.

See explanations below on Jet Engine and possible causes for frequent database corruption that can be shared with your IT department.

About Jet Engine
The default database engine underlying Microsoft Access is known as the Jet Engine.

Database corruption and prevention
Typical Causes of 'Database Corruption in Microsoft Access Database Is Suspect/Corrupted Because of Interrupted Write Operation'.  If a database is open and is writing data & Access is incorrectly shut down, the Jet Database Engine may mark the file as suspect/corrupted.  This can occur if the computer is manually turned off without first shutting down Windows or if power is lost.  Other situations may not shut down Access but may still interfere with the writing of data to the disk by Jet while the database is open.  This can occur, for example, when networks experience data collisions or when disk drives malfunction.  If any of these interruptions occur, then Jet may mark the database as potentially corrupted.

 

When Jet begins a write operation, it sets a flag and then resets the flag when the operation is complete.  If a write operation is interrupted, the flag remains set.  When you try to open that database again, Jet determines that the flag is set and then reports that the database is corrupted.  In most cases, the data in the database is not actually corrupted, but the set flag alerts Jet that corruption may have occurred.  In cases such as this, if you compact or repair, or do both, you can typically restore the database.

Faulty Networking Hardware
In this case, the file corruption does not involve the Jet Engine.  Rather, the file is literally corrupted by some outside cause.  The cause can be one or more links in the hardware chain between the computer that the database resides on and the computer that has the database open.  This list includes, but is not limited to, network interface cards, network cabling, routers, and hubs.

Hardware-based corruption is typically indicated by .bib.db files that cannot be restored through the use of compacting, of repairing, or of Jetcomp.  Hardware corruption typically occurs until the responsible hardware is repaired or is replaced.
 

Additional information

To get the utility, click JetComp utility from Microsoft.

 

For a full transcript of this article, please refer to Microsoft's knowledgebase article #209137.

 

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