GLOBAL CONSISTENCY WITH RECENCY IN DISTRIBUTED DATABASE MANAGEMENT SYSTEMS

摘要

Techniques are described that are performed by one or more database management system (DBMS) of the plurality of DBMS nodes comprising one or more database servers performing database operations on one or more databases of the DBMS nodes. The techniques describe receiving, at a QC node, a distributed query that specifying a database of a target DBMS node. Without requesting from the target DBMS node a current logical timestamp of the DBMS node, calculating a synchronization timestamp for the distributed query. In one embodiment, the calculation of the synchronization timestamp for the distributed query is based on a current logical timestamp of the QC node and one or more previous logical timestamps of the target DBMS node that were received prior to the receiving the distributed query. The QC node sends a request to the target DBMS node to execute an operation of the query at the target DBMS node based on the synchronization timestamp. The QC node may receive result set(s) from all the target DBMS nodes based on the synchronization timestamp, and aggregate the final result set to return to the client application.