Importance

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Abstract

A computer program product, such as a pre-recorded software program on a floppy disk, is disclosed, for use with a processing and database system for off-loading, to disk controller, the extraction of committed data. Responsive to the pre-recorded program instructions, the system first picks a Commit.sub.-- LSN value and insures all the data modified prior to the Commit.sub.-- LSN value is processed following the DBMS policy of reducing some disk I/Os or not for the modified pages cached in the system. If the policy is not to do disk I/Os for such pages, then the system places the identifiers of those pages in an ignore list. Otherwise, the system writes those pages to disk and empties the ignore list. Afterwards, the system forwards the ignore list and the Commit.sub.-- LSN along with information regarding the data to be processed to the controller. The controller performs the off-load function by reading from disk every page identified by the system except those in the ignore list, and determining, for each page, if the page's Page.sub.-- LSN value is less than the Commit.sub.-- LSN. If it is, then the controller processes the page and adds any qualifying data from that page to a defined answer set. Otherwise, the controller adds the Page.sub.-- ID for that page to a defined exception list. The controller than passes the answer set and the exception list to the system. The system processes the pages identified in the exception list and those in the ignore list. The system consolidates these answers with the answer set returned by the controller for presentation to the user.

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First Claim