Memory resources may be reduced to a low threshold or even become unavailable when exporting a large quantity of items which include large objects such as calendar items or appointments.  Lowering the process threads will enable the Enterprise Vault server enough time to decompress the message and convert the items for an export.
 
When too many production threads are working and the SQL server is out of connection sockets, the threads collide with each other and are forced to sleep for a period of time.  If the thread fails to contact the SQL connection socket five consecutive times, the thread generates event errors such as SQL timeouts or deadlocks and terminates the export.  This termination will be followed by a cascade of errors from the following threads not being able to complete their jobs because of their dependence on the earlier failed-threads.

The "Number of Production Threads" have a 25 thread count default setting.  The recommendation is to set this value to 10 and test exports.  If successful, the thread value can be increased slightly.  If the errors returns, lower the thread value until exports are successful.

1. Open the Discovery Accelerator client.
   
   
2. Within the DA client go to "Configuration" | "Settings" | "Export/production". 
   
   
3. Change the "Number of Production Threads" from (25) to (10).
   
   
4. "Save" the Changes.
   
   
5. Restart Customer Background Tasks or the Enterprise Vault Accelerator Manager Service.