×

Global checkpoint SCN

  • US 7,991,775 B2
  • Filed: 10/02/2008
  • Issued: 08/02/2011
  • Est. Priority Date: 08/08/2008
  • Status: Active Grant
First Claim
Patent Images

1. A computer-implemented method, comprising:

  • a multi-node database server computing a snapshot query associated with a snapshot time, wherein said multi-node database server manages access to a database comprising database data blocks;

    said multi-node database server generating a global checkpoint system change number, wherein any data block of said database data blocks that is associated with a system change number that is less than said global checkpoint system change number is stored persistently in said database;

    wherein computing said snapshot query comprises;

    said multi-node database server determining whether said snapshot time is less than said global checkpoint system change number;

    when said snapshot time is less than said global checkpoint system change number, said multi-node database server accessing data blocks of said database data blocks without obtaining a global lock for any of said data blocks of said database data blocks; and

    when said snapshot time is greater than said global checkpoint system change number, said multi-node database server accessing data blocks of said database data blocks, and obtaining a global lock on said data blocks of said database data blocks to access any of said data block of said database data blocks.

View all claims
  • 1 Assignment
Timeline View
Assignment View
    ×
    ×