Abstract: The present invention is a system and method that facilitates consistency maintenance and recovery from a system or process crash with valid data. A data consistency maintenance and recovery system and method of the present invention utilizes a dual page configuration and locking process to store and track data. A primary page is utilized as the primary data storage location and a mirror page operates as copy of the primary page except during certain stages of data manipulation (e.g., a write operation). In one embodiment of the present invention, a process can not perform a read operation if the page is locked or a write operation if the process did not lock the page. Read operations read information from unlocked primary pages. Write operations access, lock and update a mirror page, then access, lock and update a primary page. Page accesses are tracked (e.g., counted). Then a write process unlocks and syncs the primary page to disk as well as the mirror page.

Abstract: The present invention is a system and method that facilitates consistency maintenance and recovery from a system or process crash with valid data. A data consistency maintenance and recovery system and method of the present invention utilizes a dual page configuration and locking process to store and track data associated with multiple indexes of a database. A primary page is utilized as the primary data storage location and a mirror page operates as copy of the primary page except during certain stages of data manipulation (e.g., a write operation). Read operations access information from unlocked primary pages. Write operations access, lock and update a mirror page, then access, lock and update a primary page. Page accesses are tracked (e.g., counted). Then a write process unlocks and syncs the primary page to disk as well as the mirror page. A page with consistent data is copied to a page with inconsistent data during a process system crash recovery.

Abstract: The present invention provides a system and method that facilitates data consistency maintenance between two segments of memory. A data consistency maintenance and recovery system and method of the present invention uses a dual page configuration and locking process to store and track data. A primary page is used as the primary data storage location and a mirror page operates as a copy of the primary page, except during certain stages of data manipulation operations. In one embodiment the present invention facilitates consistency maintenance during a write operation to a database. The present invention also facilitates data recovery following a system or process crash.

Abstract: A computing device (12) includes a first process (16) and a second process (18) executing thereon in conjunction with a local memory (20). The local memory (20) stores data files retrieved from a database (14). The database (14) maintains the data files in page formats. Each page (22) maintained within the database (14) includes a counter location (24). The first process (16), desiring to write access a particular page (22), increments the counter location (24). The counter location (24) provides an indication that the contents of the particular page (22) are not valid. The second process (18), desiring to read or write access the particular page (22), determines that the particular page (22) is not in a valid state according to the counter location (24). The first process (16), upon terminating write access to the particular page (22), increments the counter location (24). The counter location (24) now provides an indication that the contents of the particular page (22) are in a valid state.