Restartable computer database message processing

A method for protecting database processing messages during a termination and restart, comprising the steps of:

• reading an input message;
• copying said read input message into an in-process message queue;
• monitoring a valid completion response message to said read input message;
• upon detecting a monitored valid completion response message to said input message, deleting said copied input message from said in-process message queue;
• and
• upon receiving a startup signal for restarting after a termination, accessing said copied input message from said in-process message queue;
• reading said copied input message, and, in response to said startup signal for restarting and said reading said copied input message, deleting said copied input message that has been read from said in-process message queue upon restart, whereby said deletion thereby prevents said accessing of said copied input message upon a second said restart.

A computer program product usable with a programmable computer processor having computer readable program code embodied therein, for protecting database processing messages during a termination and restart, comprising:

• computer readable program code which causes said programmable computer processor to read an input message;
• computer readable program code which causes said programmable computer processor to copy said read input message into an in-process message queue;
• computer readable program code which causes said programmable computer processor to monitor a valid completion response message to said read input message, and upon detecting a monitored valid completion response message to said input message, deleting said copied input message from said in-process message queue;
• and
• computer readable program code which causes said programmable computer processor to, upon receiving a startup signal for restarting after a termination, access said copied input message from said in-process message queue, reading said copied input message, and, in response to said receiving said startup signal for restarting and said reading said copied input message, deleting said copied input message that has been read from said in-process message queue upon restart, whereby said deletion thereby prevents said accessing of said copied input message upon a second said restart.

A data storage library for accessing redundant copies of identifiable data volumes, said redundant copies stored in a plurality of said data storage libraries, said redundant copies accessed in response to access requests, said identifiable data volumes each directly associated with an updatable synchronization token, said synchronization token indicating the relative update levels of said directly associated redundant copies, said library receiving input messages relating to said synchronization tokens, said library comprising:

• backing storage for storing and accessing said identifiable data volumes;
• an input for receiving said input messages;
• and
• a library controller for managing said backing storage, and said library controller managing said synchronization tokens in response to said received input messages relating to said synchronization tokens, said library controller:
• reading an input message;
• copying said read input message into an in-process message queue;
• monitoring a valid completion response message to said read input message;
• upon detecting a monitored valid completion response message to said input message, deleting said copied input message from said in-process message queue;
• and
• upon receiving a startup signal for restarting after a termination, accessing said copied input message from said in-process message queue, reading said copied input message, and, in response to said receiving said startup signal for restarting and said reading said copied input message, deleting said copied input message that has been read from said in-process message queue upon restart, whereby said deletion thereby prevents said accessing of said copied input message upon a second said restart.