US 12,222,914 B2
Versioned metadata using virtual databases
Hari Krishna Sunder, Redmond, WA (US); Sandeep Lingam, Redmond, WA (US); Donald Cha, Bellevue, WA (US); and Srikumar Rangarajan, Sammamish, WA (US)
Assigned to MICROSOFT TECHNOLOGY LICENSING, LLC, Redmond, WA (US)
Filed by Microsoft Technology Licensing, LLC, Redmond, WA (US)
Filed on Jun. 14, 2021, as Appl. No. 17/346,619.
Prior Publication US 2022/0398232 A1, Dec. 15, 2022
Int. Cl. G06F 16/21 (2019.01); G06F 16/23 (2019.01); G06F 16/2455 (2019.01); G06F 16/25 (2019.01); G06F 16/27 (2019.01)
CPC G06F 16/219 (2019.01) [G06F 16/2379 (2019.01); G06F 16/2455 (2019.01); G06F 16/256 (2019.01); G06F 16/27 (2019.01)] 20 Claims
OG exemplary drawing
 
1. A distributed database system, comprising:
a user database including data and a current version of first metadata;
a global metadata server configured to maintain a version history comprising changes to the first metadata and maintain a second version of the first metadata older than the current version;
a control node configured to accept a query against the user database; and
a first compute node configured to:
receive the query from the control node,
in response to determining that an existing virtual database corresponds to a fixed point in time at query begin, execute the query by referencing the existing virtual database using a virtual database identifier corresponding to the existing virtual database, the existing virtual database referencing the second version of the first metadata, and
in response to determining that no existing virtual database corresponds to the fixed point in time, generate a new virtual database that corresponds to the fixed point in time, and execute the query by referencing the new virtual database using a virtual database identifier corresponding to the new virtual database, the new virtual database referencing the second version of the first metadata.