Lendingclub Bank, National Association

Lendingclub Corporation

David Taubler

Yana Nikitina

Hyunsuk Han

Igor Petrunya

Raul Acevedo

Wira Pradjinata

Abhijit Karpe

John Daum

Techniques are described herein to handle situations in which multiple systems can change different copies of the same data item. Optimistic locking and time stamps are used to ensure consistency between the systems without incurring the performance penalties associated with two-phase commit. Specifically, when propagating a change to a data item from a first system to a second system, the second system compares the first system's 'pre-update' value of the data item with its current value of the data item. If the pre-update value from the first system does not match the current value in the second system, then a conflict has occurred. Upon detecting a conflict, both systems use timestamps associated with the respective conflicting changes to determine which conflicting change 'wins'. The winning change is applied by all systems whose changes did not win.

Mitigating race conditions across two live datastores

When a particular event record requires a particular service, but that service has failed for the event, an error record that includes an aggregate identifier (AgID) is stored for the event in an error queue. Storing an error record in the error queue causes the service to notify a remediation team to fix the failed event. All events with the AgID in the error record are put on hold and an error record is created for each of these events. The remediation team generates a fixed version of the event record and causes the system to retry the failed service for the event based on the fixed version. If the fixed version of the event is successfully processed, then any other events with the same AgID that have error records in the error queue, are routed in order of enqueue time through the event processor to be handled.

Error handling for services requiring guaranteed ordering of asynchronous operations in a distributed environment

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Oakland, CA, United States of America

David Taubler