| CPC G06F 16/214 (2019.01) [G06F 16/27 (2019.01)] | 20 Claims |
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1. A method for servicing memory requests while migrating data within a distributed database system, the method comprising:
storing, by a computer system, current assignment metadata for the distributed database system that identifies a current mapping of virtual groupings of database extents to corresponding ones of a plurality of physical storage nodes;
storing, by the computer system, new assignment metadata for the distributed database system that identifies a new mapping between virtual groupings of database extents to corresponding ones of the plurality of physical storage nodes, the new assignment metadata being generated responsive to an indication of a data migration between the plurality of physical storage nodes;
after the storing of the current and new assignment metadata and during the data migration, the computer system:
receiving a read request corresponding to a particular database extent that the data migration specifies is to be moved from a first physical storage node to a second physical storage node;
responding to the read request by 1) identifying the first physical storage node using the current assignment metadata and 2) reading data from the first physical storage node;
receiving a write request corresponding to the particular database extent; and
responding to the write request by 1) identifying the second physical storage node using the new assignment metadata and 2) writing data to the second physical storage node; and
upon the data migration being complete, the computer system identifying physical storage nodes accessed by subsequent read and write requests using the new assignment metadata without using the current assignment metadata.
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