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Preforming concurrent transactions in a replicated database environment

  • US 5,781,910 A
  • Filed: 09/13/1996
  • Issued: 07/14/1998
  • Est. Priority Date: 09/13/1996
  • Status: Expired due to Term
First Claim
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1. A method for assuring consistent data replication across a database system during concurrent execution of transactions, the database system having a plurality of application clients for issuing transactions operably connected to a plurality of database servers via a communications network, the method comprising the steps of:

  • providing a plurality of application servers, each associated with one of the database servers, such that each application server may access and manipulate data stored at its associated database server and communicate with the other application servers and the application clients over the communications network;

    designating a selected application server and its associated database server as a coordinator for a selected transaction and designating all other application servers and their associated database servers that contain a replica of data involved in the selected transaction as cohorts;

    initiating execution of the selected transaction at the coordinator and cohorts;

    forwarding, via an atomic multicast message from the coordinator to each cohort, either a commit decision, if the coordinator is able to execute the transaction, or an abort decision, if the coordinator is unable to execute the transaction;

    designating those cohorts receiving the commit or abort decision as surviving cohorts;

    receiving an acknowledgment at the coordinator that the commit decision was delivered to all surviving cohorts; and

    in response to the step of receiving, either committing the selected transaction at the coordinator and surviving cohorts, if the coordinator issues a commit decision or aborting the selected transaction at the coordinator and surviving cohorts, if the coordinator issues an abort decision.

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